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Dan's DIY ebike blog

 
pollinator
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Location: Jacksonville, FL
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About two years ago I bought the parts to assemble my first DIY electric bike (ebike). I have since built or rebuilt a few more and would like to share my experiences. I started to prepare this info last week but life chaos interrupted me. I'm thankful that Paul brought this topic up on the podcast, as I now have the time to give this the attention it needs. This is such a vast topic and I have tens of thousands of words to write up to convey half of what I want to share, so this is going to be a blog and not a manual. I intend on putting in several hours and dumping several posts in succession.

I want to preface this with two notions. First, I tend to jump into things and figure them out as I go. I have a very strong mechanical and electrical background, as well as experience with construction. I never saw a set of house plans that didn't have at least one discrepancy between different pages and had to figure things out on my own, so I gather information until I satisfy any design questions I have at the outset and run with it. The nature of DIY means using various things of various dimensions. If you need help with that aspect, your best bet is to find someone in person who is handy. This is more of a story of my journey so others can learn from my successes and failures.

Second, I fell (not riding a bike) and broke my skull and other bones in March. If I don't make sense somewhere then please don't hesitate to point it out. I will try to list resources so people can learn from the same places that I did so you can see where I am coming from. I sometimes do things in ways other people wouldn't or even shouldn't, and I will try to point these out and alternative methods to reaching the goal of a functioning ebike.

At the outset of my ebike building journey I was using an old but decent shape mountain bike. I almost made the mistake of buying lead acid batteries because the cost of new lithium ion batteries was too high and you can't tell the quality of the cells from most places. Things seem to have gotten a little better nowadays, mainly because people are willing to pay more for better quality and the market is providing that quality, but it is still possible to spend a lot of money and get ripped off. I guess the easiest way to ensure you get a quality product is to buy a name brand ebike, but those things are thousands of dollars. Most of the ebikes in the ~$1200 and under range tend to not be much better than a DIY ebike, have custom parts that are costly or impossible to find should they break, and you can't just transfer all of your parts to a different bike should you decide to upgrade in the future (I would strongly advise you use a bike with tubes and brakes that are easily sourced. You don't want to have an expensive paperweight because you can't find common parts that wear out from normal use).

Everything changed when I found out about used lithium ion batteries. Most batteries seem to either sit around hardly used/unused or get decommissioned when they have lost less than 20% of their original capacity. You can also greatly extend the life of lithium ion batteries by not pushing them to either extreme of fully charging or fully discharging the cells.

That last point is very important. I almost never fully charge or discharge my cell phone and have little discernable loss in battery life after 4 years. If you currently have a laptop or cell phone and find yourself constantly pushing it to the extreme all the time, and expect to do the same with an ebike, then you won't extract nearly as much value from buying used batteries. Or any battery for that matter. The faster you charge or discharge a battery, the more heat it produces since it is making a chemical change to store and provide power. Always charging to 100% and pushing until the battery is dead will severely reduce lifespan. It's possible to extend the life of lithium ion batteries by 7 times or more if you generally plan to only use around 60% of the total capacity, and only pushing to the extreme when you absolutely need it. Lithium ion batteries are pretty forgiving in this respect, but anything that is abused will have a shorter useful life. I would strongly advise building a much larger battery pack than you generally need, or make multiple packs to switch between versus expecting 100% capacity for every trip. If you plan for where the battery capacity is going to be in a few years then it will serve you well. If you expect more from it than it could ever give then it will be a bad experience from day one.

I caught wind of Battery Hookup on YouTube and followed the advice of someone to buy a certain type of battery pack that had the same voltage (36V nominal) as what I wanted to use on my bike. There were some things I didn't know at the time that caused some headaches involving the battery management system (BMS). Firstly, it isn't advisable to use multiple BMS's in parallel. In some cases it may work fine, but I would personally use one BMS, or use separate packs and switch between them. If one pack can't power your bike by itself then you can combine two packs and control it with a single BMS of sufficient output. Because an ebike motor is an inductive load, it can have current surges that are substantially larger than the nominal current draw specification, so I would recommend going with at least 30% higher BMS capacity. For instance, a 22 amp motor plus 30% (6.6 amps) is 28.6 amps, so a 30 amp BMS should work. A 25 amp BMS might cut out under heavy load. A 35 amp BMS might be an even better idea. You can always use a fuse of the same rating as the BMS or smaller if you choose. Too small of a fuse can be easily replaced. Too small of a BMS will definitely cause a lot of headaches.

The first batteries I bought came in smaller packs with a lower power BMS and the info I was given was, "Put two in parallel and it will work." Well, it sorta worked, but I couldn't hold the throttle down for more than a few seconds at a time, and it was worse at slow speeds where the motor was straining. I initially thought there was a problem with the motor controller and bought a replacement, but still had the same issue. Eventually I figured out the problem and learned enough about building battery packs to make my own. I took 4 of the smaller packs I bought to combine it into one large battery with 40 miles of range. I've tried the pack out on two extremely different bikes and still got the same range when testing. I live in Florida so this was on flat land on days with no strong wind.

Obviously I invested a lot of time learning to make this battery pack, but I probably spent around one third the cost of a new pack to build this one that has about 85% of the original rated capacity. Plus I can carry that knowledge forward to build my own packs and maybe help others to put them on a path to reaching their own ebike goals.
 
Daniel Schmidt
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Posts: 295
Location: Jacksonville, FL
133
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Now that I've given a run down of how I got started, let's take a look at some of the resources I used to learn and what parts I have had success with. I'll start with Battery Hook Up. batteryhookup.com has been great for me. I have purchased batteries from them on several occasions now. Shipping has taken under a week and packages have shown up undamaged. You can certainly find people online complaining about packages showing up damaged, and maybe they weren't as thorough about securely packaging things in the past, but my experience has always been positive.

Because of the nature of the business, they buy in lots and once something is sold they may or may not get any more. There are certain batteries that exist in absurd amounts, but take labor to extract (for example from all of those scooters that got plastered across cities and then banned). Others are backup batteries for critical infrastructure like telecommunications or medical devices, and there will be waves of these hitting the used market as they get decommissioned. Other times there will be packs made for a specific product and because of a design error they don't fit. Instead of redesigning an electric car, it is cheaper for them to sell the battery packs and buy new ones that fit. While you can find plenty of batteries in like-new quality, others may have been more heavily used and are usually sold at a lower price to reflect this drop in quality. For certain applications such as DIY ebikes or small off-grid solar, this can sometimes be one of the best deals. I guess the hardest part is figuring out what you want and waiting for the right time to get it. I've been very lucky that each time I bought batteries was right before they sold out of what I wanted. There are always battery packs of the same or similar type coming and going, and if you miss out it could be months before you find exactly what you want again.

Batteries come in many forms. From massive packs to a single cell. Some come without a case, some have a heavy duty case that is difficult to open or too oddly shaped to use on a bike. Some packs are sold knowing there will be some dead cells and a bad BMS, others have a guarantee that everything is functional. Some cells are metal cylinders, others are pouches. Some are not much bigger than my thumb, others are larger than Kindle tablet.

There are also different battery chemistries. I personally would suggest sticking to lithium ion (Li-Ion) because they are the easiest to use and are perfectly safe when used with proper safety equipment like fuses and a BMS. It is equally possible to make a very safe battery pack or a very dangerous one. Some of the methods I have employed in the past were not at the peak of safety, and you can find many more stories about how not to do something than you will about things actually going terribly wrong. There are far more armchair safety experts that spread doom and gloom without any experience than ones with experience. I will point out my mistakes and encourage others to do what is best for them. I've done thousands of things in my life that weren't by the book, but I had enough knowledge, understood the odds, and take my chances carefully. I briefly played the lottery when I was young and quit when I had more money than I lost. Being aware of the odds of any situation you find yourself in is better than being unaware.

I currently have no intentions of messing with other battery types at this time. Most of them have drawbacks (lower power density, higher price, charging restrictions) that don't fit my gear or my use case. There are tons of resources elsewhere to learn more, just be aware of the pro's and con's before buying.

While I have only used Battery Hook Up, I have seen others on YouTube building packs for various projects from a number of other places and nearly all of them have been happy customers. The vast majority of times that I have seen someone unhappy it has been because they didn't understand what they were buying and were sore about it. Heck, I wasn't the happiest person when I realized I had to reconfigure my packs and buy tools and supplies to make things work properly, but I was fed bad information from a YouTube video. I wasn't really mad at anybody and I'm thrilled with the price to performance ratio with what I have now.

There is another place to buy batteries that I haven't tried, but the guy has tons of informational videos. I do intend on buying from him in the future, kind of as a 'thank you' for the info he provides. Jehu Garcia's channel has lots of info for all sorts of battery setups, from cars and ebikes to power walls for houses. He often has the same types of batteries that many other sellers have, as they all buy by the pallet at auction from some of the same resources.

I already have tons of experience with electrical (2 years of school, 2 years apprenticeship, rewiring cars, 10 years of powering small things from solar in my shed) so the places I go to for information tend to go far above and beyond what is needed to build an ebike battery. I would strongly encourage anyone interested in this to learn all that you can or find someone knowledgeable. These things can be quite complex and require strong math skills and experience with batteries, wiring, and proper safety. I can't tell you how many times I've seen someone with a car try to do what worked for somebody on YouTube, possibly even got things working temporarily, and ended up towing their car or dragging me and my tools to try to fix it. I almost always just undo whatever they did rather than try to make a poorly designed system work. "Everybody's got a car, everybody's got 12 volt systems, this stuff is easy!", and they have an expensive paperweight. The world has more and more paperweights as we use less and less paper.

I don't want to discourage anyone from wanting to try new things, but this is an investment. It takes time, tools, money, and learning a few lessons the hard (and often expensive) way. I've sent a few things up in smoke in my day, but I've gained enough skills where I spend a great deal of time keeping things from being scrapped. If you are only looking for cheaper batteries, but don't want to make an investment of time or money, then I would strongly encourage you to find someone else who can benefit from this information and possibly help you with your ebike goals in the process. The key to cheap cost, reasonable quality ebikes is cheap price, good quality batteries. Buying the batteries is easy, assembling them in a way that suits your needs is the part that takes a substantial amount of knowledge.
 
Daniel Schmidt
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Location: Jacksonville, FL
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Next up I am going to dive into the non-battery components needed for a DIY ebike build. This is going to assume you already have, or at least have in mind, a bike which will be the platform you build upon.

One of the first things that needs to be decided is what type of drive system you want to use. Old brushed motors made for lead acid systems with a wonky chain drive are out of the question. Every one that I have seen was a far inferior product to a brushless motor, and the minimal cost savings doesn't seem to be worthwhile. With brushless motor systems there are generally 3 types - front hub motor, rear hub motor, and mid drive motor. While there are DIY mid drive options, I will not be covering them. There aren't many DIY options, some of them require frame modifications or a custom frame, they are in general much more difficult to install, and I have never ridden a mid drive bike.

Initially I was going to build a brushless rear hub motor ebike, but at the time the one I wanted was out of stock, I really wanted the cheapest minimal viable product as a functioning proof of concept, and then next one up in price was more than I wanted to spend. I begrudgingly bought a brushless front hub motor kit. I cannot tell you how glad I am that I got that kit! I know things will be different for everybody, but at my age I am really starting to appreciate giving things an honest try before saying you don't like something. If you haven't ACTUALLY given it a seriously try, then you don't ACTUALLY know.

My favorite part right away is that when you hit the throttle, it forces the bike to understeer and stand up straight coming out of a turn. With a rear drive, there is a certain point where you hit the throttle and it wants to fold the handlebars and kick the rear end out from under you. I've purposely pushed my newer rear drive bike to the limit on several occasions and I can tell you if I hadn't been fully prepared for it that I would have been thrown to the ground. I live at the beach in Florida and there is a fair bit of sand at the intersections of every road. This means every turn you make is on ground with less than ideal traction. As long as a car isn't coming the other way I can hit full throttle starting into the turn and the wheel will feel like a front wheel drive car in the snow. It understeers and powers through. Obviously, this isn't something you want to do all of the time as it is nice to stay on your side of the road and spinning your tire will cause excess wear. But it's really nice to know that if my balance is a little off or there is more sand than usual, I can just throttle my way out of the predicament if there isn't any oncoming traffic. Don't get me wrong, I love many other aspects of my rear drive bike, and having a heavy hub motor on the front means using more arm and shoulder strength to control a front drive bike, but I just love the way it feels in turns.

Installing the front hub motor kit was pretty easy. It comes with new brake handles that have cut off switches so you aren't accidentally pushing forward while trying to stop. You don't 'have' to install them but I would strongly advise you do. The kit I got had no display, which was fine by me. I just measured the battery voltage and used a preset path of known length to gauge my range. It came with a throttle and a sensor for pedal assist. Unless you have a problem using the throttle I really don't see the point of pedal assist with this setup. I can twist as hard as I want or pedal as hard as I want, and mix the two as I see fit. Because it is front hub drive and rear pedal drive, it is effectively a two wheel drive system, so you have more traction than a rear pedal/rear hub design.

I already had a DIY cargo shelf on the rear of my bike consisting of 2 aluminum angle brackets tying down into the frame where the rear wheel bolts on, and a piece of scrap pressure treated plywood I found and cut to fit the bike with a funky setup to clamp it to the seat post. This sat a little low down to the tire, so I made a bracket to lift it up a couple inches and cut up a rectangular cat litter bucket to stuff my batteries in and slung it under the shelf, just above the rear tire. I screwed the motor controller to the bottom of the shelf behind the battery box, routed the wires from the front to the back with cable ties, and it worked!

I immediately had to replace the brake cables and pads. The rim brakes are barely adequate at stopping the bike when they are perfectly adjusted. It seems like every bike I've looked at had flex in the frame around the rear brakes when they are applied hard, and as such never seem to stop as well as the front brakes. Maybe the bikes I've seen are just lower quality. It does look like someone with some skill could make a large metal plate with a huge cutout for the wheel to fit in and bolt/clamp to the frame in that area to reduce flex and increase braking power. There are also DIY caliper mounts for disc brakes, and the hub motors all seem to have a place for the disc, but I'm thinking the welded on mounts are far superior to clamp on brackets. My newer bike with front and rear discs is much larger yet slightly lighter, and brakes so much better than the old steel frame mountain bike. The disc brakes come with their own set of quirks, but they stop the bike very well.

As for the actual kit, I just grabbed the cheapest brushless front hub motor kit available on Amazon at the time. I've easily put over 2,000 miles on the setup and other than the battery management system issues with the first battery packs, it still runs great. There are two types of hub motors - geared and gearless. The geared ones are a bit more expensive, smaller in hub size and weight, and have a lower top speed. My rear drive bike is a geared type and does about 19 MPH, whereas the 2 bikes I've built using the gearless front hub motors are heavier, slower off the line, but top out at about 23 MPH. In both cases it seems that the motor controller is limiting the RPM, as I can load the bike up pretty heavily and still reach the same speeds. Both are considered 500 watts, although for various reasons I will delve into later, the rear drive one is more comparable to a 350 watt motor.

The exact kit I bought doesn't seem to be available, and the prices have gone up a fair bit since that time, but most of the kits are similar. Some have different wheel sizes and different voltages. I'm using 26" wheels with 36 volts nominal batteries. It is possible to find a motor controller made to handle a certain wattage motor and different input voltages, which is what I ended up doing with my rear drive, but that story is for another day. I will have to take a bunch of pictures and explain how all of that went down tomorrow.
 
Daniel Schmidt
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Posts: 295
Location: Jacksonville, FL
133
tiny house solar woodworking
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I'm currently in the process of getting ready to tear down and rebuild all of my bikes at the moment, so I went ahead and took a few pictures to let people see where I came from and where I am headed. I've recently come across a few of older bikes in really good shape with aluminum frames. Some of the old rubber is shiny but cracking, and the brakes need to be replaced, but once fixed up they should be decent transportation for getting around the beach.

This was the bike I started with. It was given to me about 15 years ago by someone moving away. I would occasionally get on a kick of riding it around, always thinking of how to electrify it with lead acid batteries but it never seemed worth the headache. Once I got it set up with the brushless front hub motor, I started riding it around constantly. Rode it so much I wore down the tire pretty far. It wasn't the best tire ever made, but it was soft and grippy. Certainly better than my other tires. Not too bad for something thrown in with the motor kit.

You can see the hub motor up front with a different tire, and the wiring all wrapped up on the handlebar as I start to harvest it for parts. The large gap between the rear deck and the tire held the battery and motor controller. There were a lot of things patched together to make the thing run, and I certainly got a lot of use out of it. The brakes were barely adequate, and one of the main reasons I am decommissioning this ride is because the lighter bikes can stop a lot quicker. There are tons of other benefits, but being able to stop safely from full speed is my main goal.

I'm also really partial to step through bikes when trying to drag any cargo around. It is a major pain having a load tied up high on a bike and having it want to spill over as you attempt to get on. I know there are a ton of other changes I need (and plan) to make regarding cargo and battery placement, but it is really nice to easily step on, and makes it easier for others to try out my bike, especially if they aren't as tall as I am.
FirstBike1.jpg
Old bike now being used for parts
Old bike now being used for parts
 
Daniel Schmidt
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Posts: 295
Location: Jacksonville, FL
133
tiny house solar woodworking
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Next on deck is one of a pair of bikes I am fixing up. They were basically bought new and put away in a garage for over a decade. A bit of rust on the chrome and rot on the tires, but the frames are in very nice condition. I currently have it strapped together just to make it work and use it as a backup for my main ride.

The battery attached to the rear tray in the cardboard box is very small for the task (36 volts nominal, 8 amp hours), and it is the first battery pack I built with individual cells and a battery management system. I spent over 6 hours assembling that small thing, but I get about 16 miles out of it, and the high current draw cells have no problem dragging me up and over a large bridge completely by itself if I decide not to pedal. I've had tons of fun piecing things together and pushing them to see what they can do, and so far I've been really happy with the performance.

My goal is to start making front 'baskets' that do not attach to the handlebars, but rather to the frame itself. I hate the feeling of a heavy basket as I try to steer and feel like I can barely control it under any condition that isn't perfectly straight. I've tried making a few prototypes that have all been failures. Not so much that they didn't function, but that they didn't look good. I seem to have a huge disconnect regarding other people's perception of positive or negative looks. I guess there is an uncanny valley where something very 'homemade looking' has a charm to it, but nothing I make ever captures that charm. I usually try to go for more of a professional look, but I don't have a factory of people and equipment to turn out my ideas, just myself and the tools I have on hand. I always go for function first, and most people I encounter seem to be of the form first variety.

After attempting two different styles and having to abandon them due to cost reasons, I extremely reluctantly bought a tool box to store important electrical bits. I'm glad I waited and found something better than the options other people told me to get, but I guess time will tell on that one. I was told to buy a fishing tackle box or some other stuff I though would be terrible. I either wanted something that matched the colors on the bike, or simple plain black. I don't know much about matching colors to make 'pleasing' combinations other than countless previous instances of negative remarks from others for getting it wrong. I couldn't possibly see some random tan, grey, or green (or mix of such colors) looking good, so I got this Harbor Freight Apache Case. I'm currently modifying it so I can add a headlight and turn signals, and bolt it to the front of the bike and possibly make a custom basket on top.

As it is, the bike is really fun if you disregard the horrible beach cruiser handlebars. The sweeping shape may be pleasing to someones eyes, but burying your elbows in your sides like a T-Rex and bending your wrists outward as far as they can go while bounding down the road is unpleasant at best. The acceleration and deceleration are really great, and the only thing missing is lights. Motorists around this area tend to either abandon all reason and slam on their brakes when they see a bike, or get aggressive with yelling and horn honking. And after seeing how bicyclists here tend to also be aggressive or completely carefree, I can see why it is a problem. I feel that if ebikes had turn signals like cars it would grab attention and be more obvious from a greater distance. Being the one with metal between my legs instead of wrapped around me, I want my intentions on the road to be obvious.

I bought several 'used' battery packs in perfect condition so I can add lights to several bikes, and I figure it could be used similarly to a car, where I could add a phone charger, radio, or other small power draw devices of convenience. I even made a power pack with four of those 8AH batteries in series to power a mini air compressor. Not that you need something that overkill for a bike, but it has come in handy on multiple occasions when journeying out to work on a car. I feel like this space has tons of room for growth and innovation, and I want to be there to see and help construct this foundation.

StepThruBC1.jpg
Step through beach cruiser ebike
Step through beach cruiser ebike
 
Daniel Schmidt
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Location: Jacksonville, FL
133
tiny house solar woodworking
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This time around I am going to give an overview of what I did to get a used ebike working. I think this might be the way a lot of people would want to go if they aren't willing or able to afford a brand new ebike, and with sales of ebikes going through the roof, there will eventually be more and more deals somewhat comparable to what I found.

My goal was straightforward - I wanted a fat bike. I was willing to do all sorts of things (and still working down some of those avenues), but after seeing just how absurdly expensive or complicated (meaning special tools, ultimately leading to complicated = expensive) I decided to hunt craigslist to find my fatbike. After many months of searching I managed to find a good deal and jump on it before it disappeared.

While this wouldn't have been much of a deal for someone to fix by replacing with OEM parts, this thing was a screaming deal for me! The reason for the deal was pretty simple - the previous owner put about a thousand miles on it exclusively going up and down the beach, and one day while wading in the ocean a wave hit it and knocked the bike over. It worked for a little bit and then the charger went up in smoke and the thing wouldn't run. I knew just buying the wheels complete with tires and tubes would cost in the neighborhood of what I paid for the whole bike, so I was determined to make this work.

I dragged it home on a Friday and by midday Sunday I was testing it out. The original battery pack had a small amount of water damage, enough to ruin a few cells. Of course I didn't have any cells to fill in for the bad ones, and reconfiguring the pack was a task for another time. So I used what I had on hand, my spare 36V 8AH battery pack from the previous post and a spare motor controller I bought for my first bike when I thought it had a problem. This bike was a 48V system, but I knew the motor would work at 36V and the new controller works with both voltages. The old controller was also messed up pretty bad and was extremely small. The new motor controller was larger, so much so that I had to modify the case and tap it in to place with a block of wood. I do intend on changing the setup down the road since there is no way to keep the large controller in there without the big connectors hanging out the top hole, and it is far from waterproof. Then again the original setup was supposed to be waterproof and the Atlantic Ocean strongly disagreed.

The rear brake cable had completely seized and the front was on its way out, so I ordered new cables. Eventually I will have to replace the pads and the calipers have some wear from the harsh conditions and have to be treated with Liquid Wrench lubricant regularly. I already refurbished one pad that came apart with a piece of automotive brake material I cut out with a coping saw and some JB Weld. It makes a bit of noise at medium brake pressure, but it grabs hard and quiet when more force is applied.

I really like the adjustable gooseneck. This bike, being a beach cruiser style, also had those outrageously terrible boomerang shaped handlebars which were immediately tossed to the side. I had found a mountain bike beaten to bits in an area where garbage is commonly dumped that had a few useful parts, including the handlebars which make this bike feel so much better. The upright riding position and step through design make it so much more enjoyable to ride. No more neck or back pain, no more worrying about spilling over. I do have to be careful with the new battery pack being dumped in the basket the way it is, because if you leave the wheel straight the weight will invariably swing the front assembly to the side with the slightest of disturbance. I will be replacing that with a frame mounted design after I get all of the quirks worked out on the other pair of bikes I am fixing up.

As is, this thing is an absolute beast going down the road. The only noise you hear is the low growling of the tires since they aren't a street tread. The original mountain bike I heard nothing but complaints from people about how it looks and this thing seems to be much more socially acceptable. I'm just so much happier with the comfort. Sometime in the future I will probably buy a new front suspension fork so I can ride a little bit harder without destroying the battery pack. I mostly baby the thing and have probably put around a thousand miles on it this year. It would easily be triple that if I hadn't been laid up with injuries all spring, because this thing feels like a Caddy compared to my first bike. It begs to be ridden and I oblige.
BigCat1.jpg
Refurbished Fat Bike
Refurbished Fat Bike
 
Daniel Schmidt
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Posts: 295
Location: Jacksonville, FL
133
tiny house solar woodworking
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Today I want to get into some of the details regarding lithium ion cells and my thoughts on what are good practices for ebikes. There will also be a lot of crossover for solar. I haven't actually made a lithium ion only solar power setup, but I have used my 145 watt panel with a pair of 50AH gel cell batteries that were donated to me to charge my laptop, cell phone, and a couple USB boost packs that all had lithium ion cells, so I do have experience in this area.

I mentioned previously that I had made a smaller 36V 8AH pack as a backup to extend my range. Normally this would be a bad idea with standard output 18650 cells (the kind that look like oversized AA alkaline batteries). The reason for this is voltage drop. Even if you go by the specs of the cells and it says it can provide a certain amount of current doesn't mean you won't have problems trying to design a system that will expect over 90% of that current. Batteries have chemicals in them that take time to react. Pushing them to their limit regularly not only causes excess heating of cells (which is why you mostly hear of high performance EV's and high power electronics having battery fires) and shortened cell lifespan, but the cell voltage will drop substantially. This means under heavy load you won't have the same amount of power that you would with cells not being pushed as hard. It also means that the low voltage cutoff of the motor controller will kick in sooner because the voltage drops below the minimum voltage threshold.

In my case I had bought cells much larger than typical 18650's and they were designed to output much more current than what I use without experiencing significant voltage drop. They had a great deal on them and it's cheaper to ship them in bulk, so I bought 80 cells. I used 10 in series (3.6V nominal for a 36V pack). For a one-off as my first pack it was a good learning experience, and it is great for a secondary pack I can take with me to extend my range. In my case, all of my bikes tend to get about 2 miles for every 1AH of battery capacity (on flat ground and other conditions specific to riding in my area). One of the things about buying used cells is finding good deals when they come along and jumping on them. There are a lot of pro's and con's to using these cells. While I do plan on using the rest for a large trike, I wouldn't use them for a bike because the cells don't lend themselves to being assembled in a shape that is good for most bikes.

The 18650 cells (the number stands for 18mm x 65mm, 0 for cylindrical shape) do have a bit of wasted space when trying to pack them together, but the numerous small cells allow for many different configurations for the overall shape of the finished pack. If you look at the packs made for certain bikes, they are sometimes stacked up to make a triangle to fit inside the frame of a bike. That plus the availability and low cost makes the 18650 cells a good option for an ebike. In my case I have been using 36V systems, and there are all kinds of various scooter packs of that voltage so you don't have to start from scratch assembling each individual cell if you don't want to go that route. Many scooter packs are a bit too small for running an ebike by itself. One option is to get multiple packs and attach the cells in parallel. For instance, I built a pack from 4 smaller packs of 10 in series and 2 in parallel (10S2P) to make one with 10 in series to keep the voltage the same and 8 in parallel (10S8P), increasing the total AH of the pack and all of the benefits that come with it (increased range, less voltage drop, less battery heating and stress for longer life).
 
Daniel Schmidt
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The next handful of weeks should be quite hectic. This week I have a few bike specific goals planned and then more bike plans mixed in with other projects. Without getting too far ahead of myself, I'm going to try to rebuild the dead battery that came with my fat bike first, followed by fixing up the sibling of the red and white bike above. I already got most of the parts in for the bike, and everything for fixing the battery pack. I haven't quite figured out how I'm going to go about fitting it back in to the bike, as I rewired things to get it running when I bought it. I might just go ahead and tear the fat bike apart and fix everything some time soon.

But for now the battery pack is on deck. It was going to be around $550 plus shipping to replace it which is why I was able to buy the bike for cheap. Since it had ocean water damage, I opened the pack shortly after bringing it home. Water had damaged the bottom of the pack, causing corrosion on some of the cell interconnects. Unfortunately a few of the cells had also started to leak, and the BMS (battery management system) died as well. I decided the best course of action would be to reconfigure the battery from 48V to 36V.

The original battery was a 13S6P configuration, or 13 sets of 6 parallel cells, each strung in series. I removed 3 sets of 6 cells to change it in to a 10S6P battery. This leaves me with a battery that is still pretty decent (36V nominal, 12AH) and removes most of the corrosion. The areas that were still corroded on top I sanded, cleaned with vinegar, and repeated until it was mostly clean. I may end up having to solder one small spot where the bridge between two cells was significantly weakened, and use a few dabs of anti seize on the other spots to protect it from corroding further. I will have to check it out after a while and make certain it doesn't start rusting again. I'm hoping to get a spot welder and nickle strip for future battery packs, and may need that stuff to go back and fix this correctly. I'm pretty confident it won't be a problem in the short term, but I won't leave it for years on end without giving it a good look.

In any event, I only have two major tasks left to get the battery functional - Add in the BMS and reconnect the cells where I lopped off the end. Because I removed an odd number of parallel packs in the middle of the series string, I have positive next to positive instead of alternating like they used to. I need to run a wire around to the opposite side to reconnect the string and get full voltage from beginning to end. After that I will remove the old BMS wires and put the new ones in place. I've been using XT60 connectors on all of my batteries because that is what I had on hand from playing around with some solar powered devices, so I'll end up using that again. They are common amongst the RC community and with the relatively low amp draw (under 30A) of my bikes it seems to work perfectly fine for my needs.

I also ended up with enough good cells to make a 5S2P pack which would be comparable to a so-called 20V (4AH) pack used on cordless tools. I haven't bought a BMS for doing that yet, but with several different bikes, solar, and tons of cells floating around, that project is going to be put off for a few months.
FatBikeBattery1.jpg
48V battery chopped down to 36V
48V battery chopped down to 36V
 
Daniel Schmidt
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Daniel Schmidt wrote:The next handful of weeks should be quite hectic.



Boy was that an understatement! I got busy with work for a few weeks after being down for a good chunk of last year, caught the plague which put me down for nearly 3 weeks making me even further behind, eventually started to get caught up and had serious plumbing issues which had me redo all the main lines in the house, broke my leg and still didn't have hot water, continued fixing the plumbing, and now haven't been able to walk without a crutch ever since. I still have issues with my leg, but I'm finally able to be upright for more than a few minutes at a time and start getting some things done, so I have been doing what I can and it is time to start this blog back up.

While I haven't completed many projects, I have gathered tools, supplies, and info which is really shaping things up into the form that I have envisioned for a long time. I'm confident that with a bit of practice I can finish converting an electric bike with consistent results and have a finished product that I can genuinely be proud of. Looks aside, I am my own worst critic when it comes to making something perform to my expectations without spending thousands of dollars to get there. Granted, much like the supposed 4 billion dollar electric scooter industry, this isn't infinitely scalable, but I think it will work out and I have some ideas on how to augment things in ways I'm very excited to share once I'm able to get started on those endeavors.

I actually started off writing the last paragraph as, "I haven't completed any projects" but that was incorrect. I had an ebike project thrust on me that I kinda wish I never did, but it galvanized me to stick to doing things the way I have been and not to do something with a low chance of success. Perhaps the things I learned will be even more valuable to others, so I'm going to make the next post about that bike to keep this one from getting absurdly long. I have stuff written up, but still need to take a picture (I'm terrible at remembering to do that) and hopefully make some progress on the next project today.

Overall I'm really happy with the things I have lined up. I rewired my fat bike with a new controller and need to mount the battery box and build a new battery pack for it. I still never finished the other pack, although I now have all the parts to do it right. I also need to work on the headlight and turn signals. I have already tested the parts and very happy with the results, so it's just a matter of setting things up. Since I can't really ride it safely, I am going to put in effort over the next week or so to get a different bike completed. It's pretty close to finished except for the terrible handlebars. I've finally decided to just buy new ones which will take over a week to show up, and with a bit of luck and effort I will have everything else done by the time the handlebars show up.
 
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This time around I'm going to detail some of the stuff I did to convert another beach cruiser to electric. Someone had gotten the cheapest brushed motor kit as a gift and enlisted me to make it work. Those kits are hot garbage and not meant for beach cruisers with their coaster brake, and I knew this would be a disaster, but they insisted. So I spent a few days fighting with that, making modifications that couldn't be undone without replacing the entire rear wheel, and after getting it really close to working, it reached a point where I would have needed to spend even more money and effort on a bike that was going to need constant attention and tinkering to keep going. In the end I realized it would be cheaper and far less frustration to just set the brushed motor and controller aside for another project and get a brushless hub motor and controller.

One of the reasons I went as far as I did was because I had heard about the first ebike Paul bought which had the batteries walk off. I looked into building a battery pack to ship up there, but apparently I would need a special license to ship a battery of that size. I considered making it as two separate pieces, but thought better of it. The bike also has non-standard connections and the brushed motor issues, and all of that messing around would make it impossible for most people to ride without turning into a disaster. Sometimes discretion is the better part of valor.

At any rate, I went ahead and built a battery box for this beach cruiser of the design I had been wanting to try out. The only issue that I have had so far is that the bike has a short light frame, had no kickstand, and makes the bike a little too front heavy when stopping. If you lean forward at all while trying to use the rear brake, the tire just slides and does very little stopping, and in an emergency it could throw you over the handlebars. The intended use for this bike is to pull a trailer around at the beach, and I added a little tray to the back so it can be loaded up even without the trailer and be safer while braking. It really isn't safe to be approaching any intersection at over 10MPH anyway, so it shouldn't be much of an issue. I may add several ounces of used car wheel weights to the back to help out with the balance. This won't be a problem with any of the other bikes and trikes I plan on building, but still good to know in case I or someone else ever tries this on a bike with similar size and balance issues.

It turned out not to have any understeer. It feels great going through turns, and I can only imagine how it is on a bigger or more balanced bike. After dealing with my fat bike having the battery in the front basket and the steering problems that caused, having the weight firmly bolted to the frame is a complete game changer. To me it completely eliminates steering issues by attaching it to the frame. The only problem I have found is that the handlebars will invade some of the space over your front basket while turning. I'll have to see how the fitment is with different handlebars and goose necks.

I also noticed a certain relationship between the geometry of the bike frame and how I went about mounting the arms that bolt to the frame and stick out over the front wheel. Pretty much everything about this beach cruiser is worse than any of the other bikes I have around, and after playing with it a bit I understand a lot more. Initially I was gong to make the mounting way more complex, but while working on that I realized it worked fine just resting the bars down on the bearing cups and bolting everything down tight so it wouldn't move. This was my first time building it this way, and it fits and functions more than 90% of the way to what I had thought it could. I couldn't ask for much more out of my first functioning prototype.

BeachCruiser1.jpg
Beach Cruiser with Battery Box
Beach Cruiser with Battery Box
 
Daniel Schmidt
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I'm back with a lot more to share in the electric bike space after falling off the face of the earth for quite some time. My leg issues are worse than they were which has severely limited my ability to get things done, or afford things to move projects forward. Fortunately I am temporarily among the walking again, and got one of those cool knee scooters this past weekend to help take the load off my lower leg when working around the house. Absolute game changer vs using crutches. I might need to do a separate thread for that.

I've moved a number of projects forward, and while I haven't fully completed any of them, some of it is worth sharing and I'm pretty close to getting my first electric trike assembled. I originally got 2 trikes from someone cleaning out their garage and they are a double-edged sword. They aren't nearly as stable as many people think from their appearance, and have some serious issues while turning. I plan on doing things to mitigate those problems somewhat, as well as gearing down the motor for a top speed of around 12MPH instead of the ~20MPH the motor was doing in its original configuration. I figure that helps both with not going too fast in to turns, as well as gives mechanical advantage should someone want to ride over a bridge with a decent amount of cargo.

Beyond this, I also have plans for two more trikes. The sibling of the trike above will be getting a heavier duty axle and a larger motor, also geared down a bit for carrying much heavier loads. The stock 15mm axles just aren't terribly robust, so the new 1" (25.6mm) axle is immensely stronger as well as having many other benefits. My main goal with this build is to make something I can use at my property to move things up and down the hill in a mostly sandy offroad environment. I'm not certain if I am going to work on this project next, but I'll give each build a good amount of attention to details and pics when I get that far.

The third trike idea is going to be of the two front wheel/one rear wheel variety.I've done a lot of research on this and I feel like for a low speed cargo trike that spending a bunch of time, money, and effort trying to get perfect Ackermann steering isn't worthwhile. I've seen a couple of other designs and I would like to combine a few ideas in to one vehicle. My plan is to make a prototype with a lot of adjustment options to figure out which geometry choices give me the handling and feel I am looking for without making it too much of a monstrosity. All of these projects are going to need a lot of pics and explanation that I will be working on in the coming weeks.

I also have a few other plans for upgrading some of my existing bikes, a large cargo bike, moving up to 48V systems that can double as power for other tasks, getting more solar involved, and possibly an offroad version of my knee scooter with a small motor so I can minimize the amount of stress I put on my bad leg. Not to mention all the stuff I've been working on with regards to trailers. In the next post I will give an update on some changes I made to my fat bike, and from there share my progress on the first electric trike build.
 
Daniel Schmidt
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I kind of need this overview to get myself on top of all the various odds and ends I've accomplished. I have a bit of brain damage from injuries nearly 3 years ago and new memories tend to fade pretty quickly where I won't remember how long ago something happened or more mundane things kind of blend together where I won't always remember offhand which repair I did to which thing and so on. I'm going to start with the simplification of the fat bike.

The original throttle was messed up and didn't last terribly long due to salt water which had damaged the battery and motor controller before I bought it. The controller I used was too big to fit the compartment and I wasn't using most of the connectors it came with. I had bought 2 more motors that needed controllers, so I took this opportunity to pull apart the fat bike and rewire everything. I saved the controller and the throttle it came with for another project and got a new controller with a smaller case. I had used an adapter cable to connect the old controller to the 9 pin connector on the Bafang rear hub motor and that thing worked great. I reused that and kept those connectors on the controller. I also kept the motor cutoff connectors so when I hit the brakes it stops the motor, as well as the throttle, power switch, and battery connector. I had no use for the other connectors, so I cut them off to save space and make it easy to get the controller in and out of the compartment.

With that job accomplished, I tied a string to the throttle cable before fishing it out of the frame. It went through a hole in the frame to keep things tidy, and I plan to upgrade my battery system in the future, so I got the wire and connectors ready and pulled them back through along with the new throttle cable. It was a bit tight but worked out well. No more dealing with the battery cable going down the outside. I have since removed the front basket connected to the fork and temporarily put the battery in the back rack, but the wiring is still there for future upgrades. I still have a hole in the motor controller compartment, but no longer have a mass of connectors sticking out and for the moment have it taped up to keep dirt and water out.

I still need to do something with the power switch. Initially I had it set up so you had to hotwire it, and have since added a power switch to the wire, but it is far from complete. I really just wanted to break things down to their most basic, and haven't had a single problem with it. As long as it has sufficient charge it just goes. I see people with 10x the amount of money invested in bikes that fail in a year or two because things are too complex and/or proprietary. I want the basic function to be rock solid. I have had regular bike issues that set me back a few days waiting on parts, such as a bent derailleur or disc brake issues, but the electric part has been very reliable.

I do plan on adding not only a second battery for more range, but also a ~12V system with a 4S Li-Ion battery. I've done some tests with various car chargers (laptop/USB) and lights and they all work well with the new battery setup. I would exercise caution going this route, as the 16.8V of the fully charged battery may be a bit too much for some 12V automotive electrical accessories, especially aftermarket components. So far I haven't had anything die on me, and the utility of having a fully functioning lighting system, as wel as USB ports for charging things is going to make the fat bike that much more of a pleasure to use.

Along those lines, I also got a new front tire. The back tire was getting worn down and the front was slowly losing air, plus I have another fat bike wheel I wanted to use for another project that needed a tire, so I switched things around. I put the new wheel and tube on the front, swapped the old front wheel to the rear, and moved the worn tire and slowly leaking tube to the spare wheel. I'm very happy with the result. Even though the maximum pressure is only 20 PSI vs 30PSI of the other tires, it doesn't feel too soft. The rubber is more grippy and has less rolling resistance than the knobby tires. I'd say from the seat it sounds about 75% quieter at full speed with just the front tire replaced. I went on a nice long ride half way across the county to a friends house where everyone was surprised I made such a journey, and made it back with no issues.

The last modification I will go into here is the trailer adapter. I needed to help someone with a serious car issue that ended up having me put a good 200+ miles on the fat bike and pulling all of my tools, jack, jackstands, and more. The trailer is one of the common ones you see for children with a canopy. My friend had given it to me with the canopy worn out, and I hadn't used it much before this. With the larger size of the fat bike wheels, it doesn't work without modification because the wheel will make contact with the trailer when trying to turn to the right. I found a scrap piece of aluminum track from an old sliding glass door and set about modifying it to permanently mount to my bike as an extension. I ended up using longer kickstand mounting bolts to hold it in place, and then made a slot to use a screw type hose clamp on the rear. I'm not much of a fan of those types of clamps, but it works well enough in this instance, and I'd imagine it would make quite a racket if it started to come loose, so I would know if it was coming apart while in use. I also need to dig up a pin for quicker attachment, as the nut and bolt I'm using requires a bit of fussing with two wrenches. I covered the top of the trailer frame in some leftover garden fencing from years past and it worked well enough. Overall I'm pretty happy with it but I do intend on going much bigger with trailers in the future. It will be a while before I get to that project but it's the one I'm most excited about.
FatBikeWithTrailer.jpg
Fat bike with trailer and new tire
Fat bike with trailer and new tire
 
Daniel Schmidt
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I've upgraded some of my tools for making battery packs, so I figured I would do a quick rundown of some of the stuff I have going on. I had issues this summer where my cheap multimeters were reading impossibly high voltages. In the case of the one that is of the type Harbor Freight regularly gives away for free, it needed a battery. I also had a larger one that had a flaky power button and it never worked right from the beginning. A lot of fussing with it briefly got it working well until it just died completely. There are lots of YouTubers that recommend some other off-brand meters that probably work great and even might come off the same factory lines as some of the other name brands, but I decided against this. Because of what I do with cells, I wanted something that works reliably to show me what a cell voltage is down to the thousandths of a volt. I didn't want to break the bank on something with more functions than I need, so I went with the cheapest Fluke model available. For this job it's one of the best options available.

I also invested in a spot welder. The cheap ones are a bit too cheap and seem to require modification to keep them from destroying themselves. Apparently the circuit that controls the string of MOSFETs (solid state electronic switches) can drop too low and cause the circuit to fail at the worst time possible, which usually leads to the MOSFETs blowing out in spectacular fashion. Supplying a separate voltage source and/or increasing the size of the capacitor is certainly a viable option. The other thing I saw was that some came with decent spot welding leads for more money, or terrible leads that wouldn't be good for the amount of use I expect to get out of this tool.

You can often find the same tool with several different names and different packages of extras and various spot welding leads, so after holding out a while I came across the one I wanted. I'm very happy with it. It does everything I expect and the leads are nice with replaceable tips. It also acts as a USB boost pack. I can charge it up with any USB source and it makes good spot welds. Not that I really ever see me needing to do so, but I could charge it up with the 4S battery packs I have and a USB car adapter, and build more packs with the cells I have in the event of a catastrophe. I already tested this out and it worked as expected.

I also grabbed some nickle strips for assembling packs and bought several feet of 4S wide nickle strip with cell level fusing. Basically it has a long thin section that curls around and acts as a fuse, so if one cell were to short out it won't continuously draw current until if melts down. This should eliminate many scenarios where battery packs could cause a fire. Most cheap batteries skip this because of cost, but it isn't all that expensive. Several dollars a pack for that extra level of protection is completely worth it to me.

On that note, I had another revelation with regards to affordable battery pack safety. I had initially planned to make an outdoor kitchen with a rocket oven before my leg bone decided to pop apart the second time (I'm starting to lose count) and got some ceramic fiber blanket. It wasn't terribly expensive, it isn't overly heavy, and it can withstand temperatures in excess of 2400*F. I figure it would cost me about $7 a battery to wrap the business ends of the cells, and even less if I started building more packs and bought a larger roll. I haven't actually seen anyone else do this (although one person hinted to a cheap safety upgrade in the future which might be the same idea). Much like the cell level fusing, I doubt you will find many cheaper batteries ever doing this, but these two ideas combined seem like a great and affordable way to minimize any chance of a fire. I'd imagine it would fare a bit worse than the salvaged battery a handful of posts back if it got dumped in the Atlantic Ocean, but some people need to learn lessons the hard way.

I've also acquired various bike tools, and want to expand my cell salvaging capabilities so it doesn't take me so much time babysitting cells for the purposes of determining their capacity and balancing them in preparation for assembly in to new packs. I like the idea of expanding things as much as I can on the DC power side of things so I can get everything capable of running off of solar, or running off of battery packs that I can load up and take with me to do remote repairs. Some of this is going to get outside the realm of ebikes, but for now I still have plenty more to share on building batteries, creating battery systems for lights and accessories, and I currently have one trike torn down and almost ready for reassembly complete with rear wheel drive.
SpotWelder1.jpg
Spot Welder, nickle fuse strip, ceramic fiber blanket, and more
Spot Welder, nickle fuse strip, ceramic fiber blanket, and more
 
Daniel Schmidt
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Now that I've gotten things caught up, I'm going to focus on the trike build. Since I've already gotten most things related to the motor squared away, I'll explain that process first. The small black beach cruiser up above with the battery box mounted to the front had a problem. I heard from a very reliable source that torque arms aren't needed with lower power motors and I would be 'fine' if you just tighten them down sufficiently. I have more experience than most people with wrenching things, and the motor was even lower power (~350W), so I did as I was told and moved on.

Well that didn't work out so well. The motor spun the axle and messed up the wires. Fortunately I had bought two of the front hub motors for cheap and just swapped it out, but that left me with a motor that needed to be repaired. Despite what various videos online suggested, I wasn't sure how easy it would be to fix, specifically getting the wires out and new ones in without bunching them up, so I left that job until a few weeks ago. I picked up an extension cable of the 9 pin waterproof variety like the motor came with and used one end as a replacement. It went surprisingly problem free for my first attempt. The new cable was slightly thinner, which might be a problem if you were overvolting, but in my case I am undervolting a 48V motor down to 36V nominal. It's extremely tight inside so you have to be clean with your work, but I had no issues unsheathing a bit of excess wire and cutting them back one at a time and soldering in place. Mine has labeling for each wire, but it might be wise to take a picture or make a diagram before removing the old wires.

The circuit board also has hall-effect sensors which was a slight problem. It wouldn't have been a big deal because the motor controller will work sensorless, but it has a split second of squirreliness when you hit the throttle without the sensors and I wanted to avoid that. It's easy to bend the leads on the sensors in the process of removing and reinstalling, but it's just as easy to straighten them out. The circuit board only had a couple screws on the inboard side and the sensors were fighting pressure from the coil wires below. I ended up having to resort to using super glue on the sensors and clamping the circuit board down. Once that set up properly, I closed it up, put it in a vise, and connected it to my fat bike to test if it worked. Full power, no weird noises, job done!

With the motor extracted from it's original wheel and now all fixed up, it was time to figure out how I was going to set things up with the rear axle. For starters the axle has a number of issues. If you have a solid axle with the rear wheels locked together it causes issues while turning, as the wheel on the outside will need to make more rotations than the inside wheel. This is something to keep an eye on in a future build, but in this case the trikes I have drive one wheel while the other spins freely on a bearing. I do like that both wheels are made the same so you can swap them back and forth. I'd imagine if someone is heavy on the throttle it will wear down faster, so you can rotate to get the most out of your tires without having to take the tires off the rims. I do have ideas for making a magnetic limited slip, but I don't have funding to dive in to that project right now and is outside the scope of this project, even if it would be really cool and helpful in the sand here at the beach.

Other issues included the bearings, which I cleaned out as best I could and reassembled with fresh lubricant. The axle itself is only 15mm with a keyway on either end on opposite sides, overlapping in the middle. These things can't tolerate extreme abuse, so the load of the rider, cargo, speed, and abuse from hitting things too hard will all add up to whether this this will continue to stay straight. Gear reduction should help with limiting the speed, and the rest is up to the rider to keep in mind. I'm not particularly abusive to machines since I'm the one that will have to fix it, but for others it is an important point to be aware of with many of the common adult trikes.

Next up is drive and brakes. I'm putting these together because of how things are set up. With the two trikes I had, there was one with a coaster brake and one with no rear brake. I like the setup with the coaster brake, because they basically just took the hub from another bike with 3 speed internal gearing and coaster brake and use it as a jackshaft between the pedals and the axle. I believe it is 1:1 in 2nd with a 33% reduction for 1st and 33% overdrive for 3rd gear. Of course if it throws either chain you have no rear brakes, and I wouldn't want to rely on that alone, even with a max speed of ~12MPH.

Unfortunately the cost and setup of a brake directly on the axle or wheels was going to be too much of a hassle, so I came up with a different plan. I haven't mounted it yet, but everything looks like it will line up well with a second sprocket going to the motor. I found that they sell sprockets that mount to the common bike disc brake 6 bolt mounts so people can drive a hub with a motor. In my case I have a hub that is a motor. They also sell disc brake adapters for other purposes that I decided to use as a spacer. I will be putting the sprocket on the outside with the spacer (to make room for the chain) with longer bolts, and a disc brake up against the hub like it would normally have when used as a front wheel. This means the second brake is also running through a chain, but between the two options there should be something that works even in an emergency. Of course by virtue of having one drive wheel, it means that wheel has to do it all. All power from the motor and pedaling goes to that wheel, and all rear braking comes from that wheel.

I got a new 24 tooth axle sprocket which matches the original. I have them side by side so the old one can line up with the hub/jackshaft/gearbox I took off the other trike and the new sprocket can go to the hub motor which has a 16 tooth sprocket. They had a few options for the crank sprocket and I opted for the smallest one which was of the 28 tooth variety. I figure this is more of a slow beach machine and if anyone did decide to ride over a bridge, they would greatly appreciate having the lower gearing. Even on my best day I probably would have ended up trying to push the thing uphill instead of trying to fight bad gearing. Not that I'm so much worried about the motor failing as much as throwing the chain. I haven't had much of an issue with this in the past, so hopefully it stays that way.
HubBrakeSprocket.jpg
Hub motor, brakes, spacers, and sprocket
Hub motor, brakes, spacers, and sprocket
 
Daniel Schmidt
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Posts: 295
Location: Jacksonville, FL
133
tiny house solar woodworking
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To continue with the trike build I will go over more of the stuff I have gotten accomplished. One of the big goals from this push is to get me to take more pictures since I am terrible about it. I've been fixing things for decades, and aside from a couple of times I took a picture of a wiring harness to help me remember things or help someone online, I never take pictures. I wish I had taken a picture of the hub motor opened up, but I think the other motor has a loose magnet, and yet another motor had a seal leak with a bit of water getting inside, so I will have more opportunities in the future.

I really dislike how much of a pain paint can be, and one small mistake is enough where it sticks out like a sore thumb and people will look at it as if you might as well have not bothered. And considering how many hours of sanding and prep work and working with toxic garbage it takes, then to have one small mistake negate all of that just plain sucks. This is why I never bother with any of this for personal items, as I don't care. Perhaps in the future I can look into using some sort of dye with flax seed oil as a finish, but those experiments will have to wait for a future project.

In any event, the wheels were in particularly bad shape, so I broke down and got them cleaned up and painted. It was quite the pain to do with the wheel assembled, but would have been even more of a pain to take them apart, and I doubt it would have come out significantly better. I did the rear wheels a while back, and didn't realize I was going to be stuck using the old front wheel until more recently. I wish there was any better option that wasn't going to cost over $100, but it looks like I'm stuck using the front rim brake. There's no point in painting the brake surface, so I'm going to clean it up as best I can and paint the rest. The fork and frame aren't too ugly, so I'm going to leave them as-is.

To limit the scope of this project, I'm also going to leave out the 4S Li-Ion ~12v battery setup and all the lights and accessories that go with it. I'd rather use one of my own bikes as the first test subject. I plan to do that in the coming weeks, but I need to get this project completed before I worry about increasing complexity.

One other wrinkle in this is I would like to set up the axle from the other trike as a little trailer. It's not so much that I want some amazing trailer, as much as I don't want to use that axle for anything else, so I might as well keep it with this trike. If anything goes wrong with any of the wheels or axle on the trike, the trailer can be used for parts to get things back in action for little or no cost. Plus, with the lower gearing and light duty axle, having a trailer to split up a load would be much safer than overloading the trike and bending the axle.

That's about it. I need to put together another battery pack. I opened up my other pack using the same type of cells and was shocked just how little drift there was between cells. I think it was around 8 hundredths of a volt between the highest and lowest cells which is amazing for cells that were used to begin with. Once I get the battery and motor mounting situation complete, it will just be a matter of getting the wires and brakes in place and adjusting everything before setting off on the first test run.
Trike1.jpg
Trike reassembled, ready for a motor
Trike reassembled, ready for a motor
 
Daniel Schmidt
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Posts: 295
Location: Jacksonville, FL
133
tiny house solar woodworking
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I managed to get the trike assembled enough to pedal down the driveway, and I forgot how outrageously unwieldy these things are. I haven't forgotten that they are dangerous, but it's been so long since I rode one that I didn't have a firm memory of precisely how much it wants to go belly up. To be fair, I did manage to stuff in a new seat post with a built in suspension which adds to the height. So it was probably set a bit on the high side for my height. Every millimeter you raise the center of gravity feels like it amplifies the danger level by an order of magnitude.

Everything else seemed pretty good. All of the bearings have been cleaned up or replaced. I didn't have the shifter installed which left it in low gear. That plus the much smaller axle gave a lot of mechanical advantage, sacrificing speed substantially. With what I am aiming for, this should work out well. I still have the old sprockets from both trikes which are different sizes and much larger. I'll probably clean the rust off and keep them with the trike in case there is any desire in the future to adjust the gearing.

Beyond lowering the rider height, there is only so much I can do to fix the unstable steering issue. The rake of the front fork is like a bike, but this really doesn't work for a trike. After you turn a certain amount, the weight of the trike and everything on it tries to turn the wheel to a full 90*. If you measure the height at the front trike with the wheel straight, it is taller and goes down as you turn the handlebar. On a bike, you lean in to a turn so you never have to turn the handlebar by a significant amount while going down the road at speed. Since you can't lean in to a turn on a trike, it forces you to turn tighter, which makes the wheel want to go to full 90* and leaves you fighting it. Even if you try to turn it more aggressively and overpower the forces against you, at a certain point the wheel stops rolling and you effectively stop turning as the wheel skids across the surface. This understeer is very much dependent on the speed you are going, and why I chose to lower the gearing of both the pedals and the motor by such a significant amount compared to my bikes.

At least I knew in advance that I was going to have to deal with this, but that test ride has kind of thrown a small wrench in the works. I originally wanted to swap out the front fork for one that is 20" instead of the oddball 24" it came with. This would have lowered the front end slightly, and mitigated part of the steering issue by reducing the angle of the front fork. I could have also gone with a suspension fork and disc brake up front which would have both been huge improvements. Unfortunately I couldn't find any front wheels to fit my needs that were affordable. Most 20" stuff is either for kids bikes, or BMX where they often don't use front brakes. Buying all of the parts to assemble my own wheel with a heavy duty rim and disc brakes plus a fork with a caliper mount was a bridge too far for the budget of this build.

Thankfully I came up with the plan to use the rear coaster brake plus the disc brake on the hub motor, and can still use the original style brake up front. The lower speed may help with the high speed steering issue, but that still leaves the center of gravity issue. I had planned on putting the battery directly on the mounts for the rear basket right above the rear axle. I could have even tried to slide the battery as close to the seat as possible, but that still puts the battery a few inches above the axle center line, and I feel that simply isn't low enough. At best it won't make the handling much worse than it is, but that isn't good enough for me.

That means I will have to go back to the drawing board and come up with something better. A front battery box is way too high, so that's not an option. If the battery were smaller like a typical 10AH - 15AH frame mount battery then it could be mounted to the step-through frame as low as possible. I'm making a larger battery for a number of reasons, including range, voltage drop, and the fact I am using used cells. Doubling the capacity ends up more than doubling the range because of a number of factors like heat and voltage drop. Or maybe I should say after using the larger battery, that trying a battery half the size cut down my range by more than half. So I'm sticking with my 10S8P battery pack size that has worked exceptionally well for me in the past.

That leaves only one option left for placement - below the axle and under the frame of the bike. Given that I can only go so far forward before getting to close to the pedals, and the seat is so far back as to be close to the rear tires, it shouldn't have any issues with bottoming out. The pedals and rear tire will hit most things before hitting the battery box. I'm still going to make it robust enough to protect the battery, and might come up with some sort of suspension. This will both protect the battery from jolts while riding, and also allow the battery a bit of room to move upward if someone were to try the implausible and ram it in to something while risking their legs and the rear tires in the process.

I wish there were easier ways to quantify how unstable 'delta' style trikes are and how various changes affect the stability. I'm always coming across people saying they wish they had one because they think they are more stable. If a kid can ride a trike then it 'should' be easier for an adult, right? If only it were that simple. I've seen a number of other ways to mitigate steering and stability issues, and I hope to explore them further even if I can't justify it for this build. Hopefully some of this information can help others looking at this style of trike. If someone is looking to buy one I recommend finding one you can sit on and ride, even if only for a short distance so you have an idea of what you are getting in to.
 
Daniel Schmidt
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Posts: 295
Location: Jacksonville, FL
133
tiny house solar woodworking
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The next few parts to the trike build are rather time consuming. I need to clean up all of the wheels. Since I'm not mounting the battery under the rear basket, I can focus on just making a bracket for the motor, brake caliper, and build in a trailer hitch. Building the battery is a tedious task. I've had a bunch of other tasks that I needed to complete in order to be able to do some of these parts of the project.

Having to reinvent the wheel several times over is much more time consuming than rebuilding an entire car. With a car, if you have the skills and the tools, you generally don't have to worry too much about the fitment of pieces, or if one change is going to cause a chain reaction of throwing everything out of position. You simply get the parts, install according to the manual, and that's it. This is where a lot of people customizing cars can get in trouble, where trying to get the 'best' components for several parts ends up making the car louder, or narrower power band, or the suspension too hard or unwieldy, and can end up with a worse car and an empty wallet.

That's part of the reason why I'm not going all in with every change I can think of on one build. It's easy to add weeks worth of work figuring things out, undoing work you did previously because of changes to plans, and it can get expensive fast. As the old saying goes, discretion is the better part of valor.

A big time sink has been getting all of my tools together and in shape to do what I need. I'm going to need to weld to make parts for the motor bracket and battery box. I probably haven't used my welder in over a decade. I got a new spool of better quality wire than whatever I got from Harbor Freight. I opened it up and got all of the dust out and the power cable that I had upgraded wasn't seated in the bushing properly, so I got that fixed.

The batteries in the welding helmet went bad and I happened to have a pair of new batteries to replace the old ones. You can solder them in place, but since I had the spot welder, I decided to try that out on a real project for the first time and it works really well. You have to clean all of the surfaces, otherwise oils from your fingers or from manufacturing will cause issues, but I was prepared for that. I might need more rubbing alcohol by the time I'm done cleaning all of my cells.

And boy do I have a lot of cells! I am going to go ahead and get my spare fat bike battery put together, the battery for this trike build, and the battery for the next trike build. Fortunately I had gotten all of the cells pretty close to where they needed to be voltage wise a few months back, and they all held their charge well. But I still had to triple check everything. Plus with the better multimeter, I can get the charge much more accurate. The first battery has 60 cells, the second 80 cells, and the third one has 112 cells, so that was a ton of babysitting and making certain that everything was ready to go. The used packs had some plastic housing pieces that needed to be trimmed, along with bits of metal strip that connected them to the old BMS's that had to be removed, so that too ate up several hours.

Assembling the packs with the new spot welder should go a lot faster than previous builds. I still haven't tried out the nickle strip with cell level fusing. It should work well, but it needs to be cleaned off without wrecking the little pads, as they get caught on things easily and bend out of place. I might build a small tool battery to test it out and get the spot welding power setting dialed in. All of the welding, spot welding, painting, and more is going to take at least another week.
 
Daniel Schmidt
pollinator
Posts: 295
Location: Jacksonville, FL
133
tiny house solar woodworking
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Things have progressed a lot with the trike this past week. There was a fair bit of struggle trying to build things from scratch, and as mentioned before I had to limit the scope of certain changes. Part of it was to limit how much time is sunk in to this one project, and some of it was simply my lack of welding skills. I've gotten a bit better but still have a ton to learn. My main issue which seems to be common is fixturing. I used whatever C-clamps and magnets I could find at the moment and dove in. Having more clamps, magnets, right angle jigs, and a proper table to work on would have helped tremendously, as well as better stock. None of that was in the cards, so I just did what I could.

I'm mostly happy with the outcome. The brake setup worked out way better than I thought it would. It didn't take much time to get it work. I was fortunate that the one part of the bracket was close enough that I simply needed to make a caliper bracket out of a flat piece of steel, and the built in adjustments were enough to get it lined up tight. I got the motor in really close to the axle which I'm guessing will help avoid chain issues, and not protruding too far back. I made a chain tensioner to help keep the motor from torquing the bracket out of square, however I haven't given it a full test yet. It may need a bit more reinforcement, but I'm hoping not to need to redo the entire bracket.

My first test across the yard without a tensioner showed that it does work, and it does absolutely need the tensioner. I saw in advance that the chain might slap the frame to the axle and put something on to protect it. The chain got loose but never came off, so hopefully the tensioner is enough. I took it all apart to make the tensioner which I finished yesterday, and next I need to get it painted. It's my least favorite part of any project, but I don't have any other viable options at this time. I also need to paint the basket and eventually the battery box when I get that finished. I'm doing everything I can to avoid painting any more parts. Once I get things closer to completion I will take more pics to show exactly how it works.

I spent entirely too much time trying to remove rust from the basket, wheels, and various parts. On the one hand I really wish I never got involved in burning so much time on it, and on the other hand I'm glad I am able to get this project nearing completion instead of scrapping everything. Maybe I should have tried something like vinegar, molasses, or Evapo-Rust, but it's too late now. The battery box and painting will eat up a few days time that I'll never get back, but I'm this far in and the test ride yesterday definitely helps me see that the end is in sight.
TrikeBracket1.jpg
Not-so-pretty first welding project
Not-so-pretty first welding project
 
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