Generating electricity off-grid with used veggie oil

Hello friends, the google searches have once again left me high and dry.  Nothing but crappy articles about something not-quite-related to my search or ads for something similar but clearly not what I want.  So I turn again to the best resource on the planet.  Permies.com

Background: This past summer at the PTJ I was discussing options to ditch the grid power at my place.  I'm aiming to disconnect from the grid fully.  The sun is too low in the sky in winter along with the number of trees on my property to make solar possible.  The miles of trees around me make wind generation dicey.  No running water either.  A wonderful gentleman (Jim Juczac) suggested running a generator on veggie oil or biodiesel for all my power.  I recently found a free source of 30 gallons a week of used fryer oil.  Suddenly this becomes a possibility.  I'm going to seek out a few other sources as back-ups before I spend any money on this.

Plan: So my hope is to get a generator that can run on straight filtered waste veggie oil.  Have it hooked up to a battery bank in the house.  Size the batteries to hold a day's worth of usage.  Have the generator come on at 4am every day and run until the batteries are full.

According to some math, I think I need around 18 KWH of juice per day.  So a generator in the 6-12 KW range should be a good size.  That would use about 1.5 gallons of oil a day.  Now for the questions:

Q #1: I found one generator that is designed to run on veggie oil without any tinkering: Organic Mechanic 12KW.  That would be awesome but it's kinda pricey.  Are there other veggie oil generators out there that I could be considering?  I found another one in Germany but I haven't heard back on if they distribute in the US (Heipro)

Q#2: I've seen that you can make "pseudo-biodiesel" by mixing WVO and diesel (50/50), WVO and gasoline (80/20), WVO and kerosene (70/30) or WVO and pure gum turpentine (80/20).  That seems a lot better than the official way of adding methanol and lye and getting a 10% waste product of glycerin.  Has anyone run one of those mixes in a generator for lengthy periods of time with (or without) success?

Q#3: I could find a cheaper, good, old diesel generator and try to work with it but I'm quite worried about the controls to make it "automatic".  I don't want to be starting and stopping it myself every time.  Is this easier than I'm thinking?  Could I cobble together a nice low rpm generator into a system that will work reliably for me?  Keeping in mind that I'm apparently not great at electrical controls.  Even the word "relay" worries me...

Q#4: Assuming I get this generator and it runs well, is it easy to tell it to come on in the wee hours of the morning every day?

Q#5: The place where I'd put it is a long way from the house (~300') with an empty conduit between the two (yay).  But there is a sub panel near the location (only 20' away) with a 95+ amp supply.  But it's not warm there (gets down to 10F once a year).  So I assume the batteries need to be in the house.  How do I connect the batteries to the generator?  Do I need a big ass feeder wire running from the generator all the way to the house batteries and then onto my personal house grid?  Or can the generator somehow put juice onto the grid out at that subpanel and then the batteries in the house collect it?

Q#6: I assume there would be a charge controller and inverter somewhere in this chain of hardware.  Both of them in the house by the batteries?  Would the charge controller be able to tell the generator to come on at 4am?

Q#7: I was assuming I'd want lithium iron phosphate batteries since they'd be in the basement.  Since I only need a day's worth of juice it might be a small battery pack (yay).  Are those assumptions decent?

Q#8:  If the brains of the operation (charge controller, not me) is in the basement, I'm assuming I'd need to run a control wire out to the generator.  I only have the one conduit so if I need power and controls running between the house and the generator, I assume I'd have to run that control wire separately in a new trench.  Is that right?

Thanks so much for any guidance I can get on this little pipe dream of mine!

Q1: WVO if far thicker than standard diesel, so adaptations need to be made to make it work in a standard diesel engine.  The most common one I've heard of is a pre-heater, that warms the WVO to the point it will flow properly.  The pre-heater conversion kits I've seen work on a dual-fuel principle, starting the engine on standard diesel, allowing it to get hot, the switching over to WVO once it gets thinned.

Q2: The purpose of blending is to make the fuel thin enough to pass through the injectors.  I would avoid turpentine completely.  Diesel #1 or kerosine mixed together would be a better option.  Even transesterfication with lye and methanol makes biodiesel that is still a bit on the thick side for most diesels.  In winter, solids tend to precipitate out..

Q3&4:  Good luck with making it automatic!  This is going to be experimental, and what I've found is even with a well-running solar system, it very much needs attention.  In your case, trying to walk away and let the system run it self is asking for trouble.

Q5: This is where the inverter comes into play.  Almost all inverters are designed around solar today, but at least mine, the Schneider XW+ 6848, has a built-in generator charging circuit.  This inverter has ACout terminals to go to your electrical panel, and ACin terminals for either the grid or a generator(both).  The 240VAC from my generator goes into my inverter via ACin2, connecting L1, L2, N, and G.  So, the inverter is powered by the 48V battery string, and the inverter accepts generator power and converts it to DC to charge the battery bank.

Q6: If there is no solar, there does not have to be a charge controller.  I've never programed my inverter automatically start my generator, because I am very worried about that.  Murphy's Law you know.

Q7:  Be very careful about Li batteries.  If they receive a charge while cold, they can be physically damaged.  I've heard of Li batteries being destroyed after only one charging episode while the batteries were at 32F.  Traditional lead-acid batteries like Rolls will give you many years of service if you do the recommended maintainance.  But, if you are a walk away and forget about it kinda guy, you will ruin them.

Q8: My understanding is the the latest control box for the XW+/XWPro is wireless, so you "may" be able to do this remotely.  That being said, that's NOT how I do it, so I can't say from personal experience.  My gut intuition is that it's not likely to work well for you if your goal is to simply walk away and take care of it from the comfort of the house.

Will Prowse is your go to source for any kind off grid power:
https://www.youtube.com/channel/UCoj6RxIAQq8kmJme-5dnN0Q

You can buy an all in one inverter/charge controller for a couple of thousand dollars, many of which have a connection for a generator to just plug right into the charge controller when your batteries are running low.

I don't know anything about generators, so I can't comment on fuel source etc.

Q4 - that depends entirely on your generator

Q5 - If you go with the charge controller/inverter with  generator input, you can just wire it into that and off you go.

Q6 - See above.

Q7 - Yes. Lifepo batteries are the way to go, especially if you're in warmer environment. Here in Canada we have to be a little more concerned about the lower temperatures.

Q8 - Yes. The more expensive ones will have a control wire to turn on a generator.

Also, this kind of charge controller is more often linked with solar panels. Buying the right one, will allow you to add solar panels over time.

Thanks gentlemen!  I heard back from hiepro and they don't sell in the US.  And I found a second source of free veggie oil.  I'd like to identify at least 3 sources before I jump in this direction...

So I'm hearing that it's unlikely/risky that I could get a generator to come on automatically for me on a schedule.  That's too bad.  If I'm manually starting it, I think I'd want a bigger battery bank so I wouldn't have to fiddle with it daily.  And I'd want the generator closer to the house but more insulated against noise.

Ok, here are some more questions (additional answers to the first batch are very welcome!)

Q9: If the batteries are in the house, how do I get the electricity from the generator to the batteries?  Do I need a supply wire/cable running from the generator to the inverter in the basement and then to the batteries and from there back through the inverter onto the house grid?  OR can the generator put the juice right onto the house grid at its distant sub panel and then in the basement, the inverter can recognize that and start charging the batteries?  Or do I turn on the generator, have it's juice going onto the house grid (likely idling), then go down in the basement and hit a button on the inverter to start sucking juice off the grid which would kick the generator up to speed?

Q10: Is it more reasonable to have the generator automatically kick on when the batteries get low (not on a schedule)?  So it's automatic in that sense?

I'm curious about the salt content of used fryer oil, and the potential impact on a diesel engine. Thoughts?

From what I've read, veggie oil is better on diesel engines than diesel is.  Don't they salt the food after it's out of the fryer?

I don't know anything about generator, but local john deere plant burns used engine oil and cooking oil in winter for heating purpose.

Mike Haasl wrote:From what I've read, veggie oil is better on diesel engines than diesel is.  Don't they salt the food after it's out of the fryer?

When Rudolph Diesel invented the diesel engine, he demonstrated it with peanut oil. Vegetable oil is not that dissimilar. From my understanding the only issue with WVO, is when it gets cold it becomes more viscous so the engine might have trouble getting started. Others who have been using veggie oil sometimes have 2 tanks. The main tank has the veggie oil in it, and the auxillary tank has regular diesel in it and they switch it over to regular diesel and leave it running a little while once they are done so the fuel line is filled with diesel. This allows the engine to start using regular fuel and once it's up to temperature, they switch over to veggie oil for the bulk of the work. Of course this isn't going to be so helpful when you're running the generator automagically.

How hard is it to drain the fuel tank? Because one option for a generator might be to store the fuel someplace warmer.

I keep both my generators and my battery bank in a two car garage that insulated and finished. I further insulated the battery bank with foam board insulation. My understanding is the batteries last longest if kept as close to 70F as possible. My inverters can be programmed to turn the main generator on when the battery bank reaches a certain point and then will turn off when the battery bank is full but I have solar so I don't use that feature. I would think that you could attach a timer like we have for our well pump, to turn on the generator at a specific time and off at another time. My concern would be that the generator might not need to be on the whole time if you haven't drained your batteries. My generator sounds different once the batteries are full but I don't know if that's true for all generators.

Question - if you are using an AC generator why would you need an inverter? Is it because the power is stored in the batteries as DC. I have one AC generator and one DC generator. I can use either of them to charge the battery bank but it does all go through the solar system. Apparently the DC generator is more efficient.

Mike Haasl wrote:From what I've read, veggie oil is better on diesel engines than diesel is.  Don't they salt the food after it's out of the fryer?

I guess it depends. Some restaurants have pre-breaded, pre-seasoned frozen products that go straight into the fryer.

Salt, if present, shouldn't be soluble in oil, only in the traces of water in it. I don't know if that settles out at the bottom. You would think so though.

It's entirely possible that I'm talking 100% BS. Apologies for the hijack!

Q1) what about a diesel tractor and a PTO generator? Then you'd also have a tractor... Or maybe find a donor diesel car, and a generator head.
Maybe you could install a remote starter like the city folks have for their cars... could even be up on cinder blocks like the country folks have for their cars...

Q2) Mark Shepard mentions in an interview (Kirsten Dirksen on YouTube?)  how his biodiesel method is mix it up and come back later, rather than tending a fancy reactor setup... funny, I've been thinking about this all week! and meant to re-watch it, if I do, I'll come back with a link.

Q8) I think you do have to keep high voltage and low voltage separate. You might want some separation (18"?), possibly even use shielded cable for the controls?

Kenneth Elwell wrote:Q1) Or maybe find a donor diesel car, and a generator head.
Maybe you could install a remote starter like the city folks have for their cars... could even be up on cinder blocks like the country folks have for their cars...

That's a great idea!

No such thing as a free lunch! There's always a cost to anything "free", unless, of course, it's given with Love! If you want an automatic system, the cost is the straight diesel fuel that it needs to run on. If you want to run your generator on veggie oil, the cost is the chore of starting AND stopping it manually! A diesel engine will start up just fine on veggie oil in the summer but in the winter, without a heated engine house and fuel lines, no chance. If you try, you'll bust something, most likely the injector pump or whatever drives it, as a friend of mine found out. His car ran fine on fish'n'chip oil all summer; come the winter, the pump jammed up, took out the timing chain and the valves went through the piston heads. One scrap engine.

On an off-grid system, you won't want to use your precious power to heat the engine house or the fuel lines. You will need to insulate the engine house well (not forgetting to allow for ventilation) and the insulation will help to deaden the noise enough to move it closer to the house. The engine will need an auxiliary tank for diesel, a changeover tap to switch between diesel and veggie oil and electric heaters for the fuel filter, fuel lines and the injector pump, which will run off the generator. The engine will be started on diesel and you'll change over to veggie oil when everything is nice and warm. When the batteries are charged, you'll change back to diesel and run the engine long enough to get the veggie oil out of the system. You should be able to tell when that is by the smell of the exhaust. It may be best to use a separate fuel filter for the diesel and have the changeover tap just before the pump to minimise the time to clear the veggie oil out. That will leave everything ready for the next start.

The generator should be 120V or 120/240V, which will allow you to run things off it direct, rather than through the inverter. The battery charger will run off 120V (or even better, 240V if you can get it) and the high current, low voltage lines to the batteries should be as short as possible to keep down resistive losses.

Batteries: I'd avoid lithium batteries, not least because of fire risks. Lead acid is best, preferably batteries specifically made for solar power duties. They will probably be 2V each and you'll hook them up in series to get whatever voltage your inverter runs on: 12, 24 or 48V. Failing that, golf cart batteries are quite good, so I've heard, and so are traction batteries as used in electric fork lift trucks etc. Both will cope well with deep cycle discharge. On the other hand, car batteries will not cope and will be dead after only a few cycles. Leisure batteries will be slightly better but still not good. Whatever you use, they must be in a well ventilated space.

If someone offers you some NiFe cell (pronounced "knife") batteries, they'd be good as they last for ever, literally. They have caustic soda for electrolyte, which can be changed occasionally with advantage and they also need topping up with distilled water if outgassing heavily. They do have a wider range of operating voltage than lead acid batteries so be sure that your inverter can cope with this. There are companies that offer solar power systems using NiFe cells.

Whatever you decide, the best of luck with it!

It looks like they aren't selling kits anymore, but the greasecar web site might be of interest. Their system starts on diesel then after the engine heats up you can switch to used vegetable oil. The engine heat warms up the vegetable oil so it will flow through the injectors. Before shut down, you must switch back to diesel and purge the vegetable oil. This does not sound very feasible for automatic start / stop but it could probably be done with some effort. A water cooled diesel generator would be needed to preheat the vegetable oil. Here's the link to their web page which includes Technical Resources and FAQ sections:

https://www.greasecar.com/

There is also a book about running cars on vegetable oil, "From the Fryer to the Fuel Tank" by Joshua Tickell.

Q9 - As for system design, the generator will create either 120 volt AC or 240 volt AC power. It can be located a reasonable distance away from the batteries and inverter / charger which are normally close together. If you add some PV modules, their charge controller is also typically close to the batteries. This is driven by the relationship between power, voltage and current. For a given power of 1000W, at 240V the current is 1000/240 = 4.2A but for 1000W at 12V (battery voltage) 1000/12 = 83.3A. The higher the current, the thicker the wires need to be to prevent power loss and voltage drop. Higher power systems usually use 48V battery banks for this reason.

My system uses Schneider (formerly Xantrex) equipment. It includes an automatic generator start (AGS) controller. This unit allows setting different generator triggers for start / stop. Mine starts the generator when the batteries drop to a programmable voltage setpoint. As soon as the inverter/charger sees the generator come on, it waits for it to stabilize then automatically switches over and starts charging the batteries. The inverter also passes the generator power through to all the loads. If a heavy load starts the generator may slow down causing the inverter to disconnect it briefly then reconnect. When the generator stops the system goes back to the inverter output automatically. This is all transparent to the loads so computers don't crash, etc.

The generator is water cooled diesel based on a Kubota tractor engine. It includes a start control module which handles all the glow plug preheat timing, cool down, etc. You might be able to use something like it to handle the switch over from diesel to vegetable oil. The Schneider AGS might also be able to do this, it has a lot of options. The AGS in my system just closes a relay to short the start wires together when the generator should run. The inverter talks to the AGS so you can set it to stop the generator with a few different options. Mine turns off when the charger ends the absorb phase indicating the batteries are charged.

Q10 - We are totally off grid and this setup has run without issues for over 5 years using lead acid batteries. I just switched over the LiFePO4 batteries and only had to change the setpoints for charging voltage and the automatic generator start. It has programmable quiet hours when the generator won't run. Otherwise, it only runs when it needs to rather than on a specific schedule. That is probably better for battery and generator lifetime.

As Andrew said, Will Prowse has a lot of good info. Be sure to check out his forum site where you will find lots of good stuff and people willing to help you with specific questions:

https://diysolarforum.com/

Some food for thought: 18kWh is a lot of power to generate and store each day. You'll probably need to run a 48V system with at least a 6kW 120V/240V inverter. A DIY LiFePO4 battery bank of 16 280AH cells can store 14kWh. For maximum lifetime, normally you only want to use less than 80% of that so you'd need twice as many batteries. One set costs around $3,000 if you build it yourself from decent quality Chinese cells shipped from US stock. Commercial LiFePO4 batteries will be a lot more expensive. The water cooled diesel generator I bought should run for 25,000 hours with routine maintenance since it turns at 1800 rpm. The air cooled diesel generators turn faster and probably only run for 5,000 hours. A Lister will probably run forever but I'm not sure about getting 12kW out of one. If you run for 2 hours a day, 5,000 hours is about 7 years. If you get a portable gas or LPG generator for around $1,000 and run it that much it might last 2-3 years before the inverter will stop accepting its power. I'm not sure if a diesel generator will have that issue (declining power quality). A separate AC powered battery charger would probably work OK for longer but the inverter inputs are finicky. Anything you can do to reduce power consumption is going to be worthwhile.

Douglas Alpenstock wrote:.....Some restaurants have pre-breaded, pre-seasoned frozen products that go straight into the fryer.

Salt, if present, shouldn't be soluble in oil, only in the traces of water in it. I don't know if that settles out at the bottom. You would think so though.

It's entirely possible that I'm talking 100% BS. Apologies for the hijack!

I have no experience with any of this except for running a gennie from my tractor and plugging it into a transfer switch on our power pole during emergencies.  With respect to the WVO and salt, wouldn't this have been addressed somewhere by the many decades of use of WVO in diesel autos?  I totally get what you are cautioning and never thought about how this might effect engine performace in a diesel that is running on WVO, but it just seems like there should be something out there on the internet about this issue.

How about putting your setup in an insulated building with a waste oil burner to heat it? It sounds like you can get far more oil than you can use already so it won't be a strain to burn some extra. You could theoretically heat your house with it at the same time using underground lines to your home radiator system like a wood boiler.

I have been running various diesels on SVO for 15 or so years.
I do not recommend bio or blended unless no way to avoid them.
The first decision has to be a veggy friendly engine.
The older the better. 90's and earlier are better with less electronic controls and simpler injection systems.
My best experiences have been with 1991 vw's, 1991Mercedes 300D turbo diesel, and a 1994 Dodge 12 valve 5.9 turbo diesel. They all run fine all summer with a little diesel, kerosene, or gasoline added.
The only real problem is viscosity.
They can run year round if the engine and fuel are kept warm enough. The temperature varies with engines but probably above 60F or 70F.
My Dodge is too big for your needs tuned for 400 horses. Even the Mercedes is probably too big. I think VW'S are 40-50 horses and very efficient. And they are every where. You just need to figure out how to drive a generator.
So for MANY REASONS I recommend you put your veggy generator  in a warm place as close to your basement as possible and spend your money to do that instead of an over priced generator.
A shed housing an outdoor furnace could be ideal. You might want to put your batteries there too.
And you might want to run your generator when you are using the most power directly from the generator if it is big enough to do so while charging the batteries. That would be the most efficient.
I also recommend some solar panels. They are getting cheap and half of the cost of the system is batteries and charge/inverter system.
Don't fall for expensive heating system scams that heat the fuel tank. HOW MUCH WARM FUEL DO YOU NEED? You might use a gallon or 2 a day very slowly.
Also DC wires lose more power over distance so they MUST be kept as short as possible. So it would best if the generator, batteries, inverter, charge controller, and if applicable solar panels are all together.
The first step is a lot of planning including how you can reduce your demand on the system like solar or wood heated water and reducing or eliminating refrigeration, AC and heating, or freezers, water pumps, and cooking. They are the biggest loads.

I also use veggy in some tractors including a compact 3 cylinder Massey Ferguson 1120. I bought a generator head to run from the PTO.

Good luck,

All the restaurants here in Montana change their cooking oil at least once a week and they will give it to you free.  With a filter it would fire your engines if the work on cooking oil.

Solar panels are so cheap these days, you definitely want some.  I understand the tree issue, dealing with it myself.  

I have come to the conclusion the cheapest option right now is to get enough panels to meet your needs for the summer six to eight months, with 2-3 days of battery for basics, with an efficient generator to supplement in the winter and cover past two cloudy days and any high demands like heavy tool usage.

You do NOT want to NEED to run the generator every day, especially with WVO.  Just from a financial pov, you will spend at least a half hour of diesel and time for startup and shutdown whether you run the generator for two hours or twelve.

On the wvo, you need to figure out how to filter it efficiently.  My friend used a centrifuge to avoid buying so many filters, but it had lots of babysitting issues, too.  His garage floor had  been oiled multiple times before he finally set up a containment system.

Thanks everyone for all the great advice!  Reconciling what "should" be doable against what's practical is a valuable exercise for me.

A couple more reference points...  It gets kinda cold here in the winter.  -30F is an annual occurrence with a couple months where it never gets above freezing.  We'll also go 2 weeks straight with overcast skies in Nov and Dec.  I would might some day add some solar if I can figure out a spot that will get more than 3 hours of sun a day in winter.

I'm still a bit unclear about Question #9.  Can the generator feed juice onto my household grid at a distant subpanel and then the inverter and batteries could be 100 yards away in the house?  Or do I need a dedicated wire that feeds power from the generator to the inverter?

Q#11: Per R Scott's comment, how long would it normally take to do a start up and a shut down in the winter?  I was thinking you'd start it on diesel, hit some buttons to start some electrical heaters heating the WVO pump/filter/lines, and then after 5 minutes, change over to WVO and walk away.  Then when the batteries are full (or you hear the generator start idling?), go out there, switch back to diesel and wait 3 minutes and then turn it off.  

I spent a few hours watching some of Will's videos last night.  Very helpful, now he needs to get a veggie generator :)

Jim Webb wrote:Batteries: I'd avoid lithium batteries, not least because of fire risks.

Jim, this is a bit surprising to me.  I know phones or small batteries sometimes burst into flames but I thought the bigger packs, especially ones that aren't DIY, were safe.  I mean there are two in my wife's prius..  

Thanks M Rives for the info, I'll check out those links tonight!

About 10 or 12 years ago, I was still living in a typical urban house with a garage, and was interested in going "off-grid" within the city.  I didn't have the resources then that I do now, but I stumbed upon the website https://www.utterpower.com/ which led me down a rabbit hole ending in me ordering a set of parts to build an Indian made Lister CS 6/1 diesel engine.  I built a base for it using 1/2" thick steel plate on 4"x4" lumber, then proceeded to build the engine per the instructions.  Entirely from parts.

It took me all summer, and was great fun.  In the end, I finished it, started it up to a running idle for about 10 minutes, and shut it off.  I never did order the generator head to complete that project, and ended up selling it on Craigslist to a guy from Indiana.  Along with a full tote of filtered veggie fry oil I was collecting from a couple local bars for a while.

I made a small profit off the sale of the engine, but I sold it mostly because my wife wanted it out of the garage.  I've recently been thinking about redoing that project, this time to completion, as a co=gen project at my house on 14 acres.  The not-small 6 horsepower (max) engine is water cooled, and can be used with a few water lines under the floors for additional winter heat.  

This time, I might use a Raspberry Pi Zero as a smart-governor; have it idle at 450 rpms when there's not much demand for AC power.  Maybe use an efficient DC alternator (from an RV, perhaps) instead of an AC generator head, so that I can integrate a solar array some day.

Hmmm.  My wife's going to be mad....

I did hear of somebody who ran a Lister 24/7.  Then it stays warm for the veggie oil, generates heat for any cogen needs nearby and is pretty fuel efficient when idling.  Not great efficiency but good.  Not sure about the emissions but if it's veggie emissions, they're probably a bit healthier for the neighborhood.

Mike Haasl wrote:

Jim Webb wrote:Batteries: I'd avoid lithium batteries, not least because of fire risks.

Jim, this is a bit surprising to me.  I know phones or small batteries sometimes burst into flames but I thought the bigger packs, especially ones that aren't DIY, were safe.

When it comes to high-energy technologies, "safe" is always a relative notion.  Lithium is both toxic and highly flammable, but so is gasoline.  Everything has it's downside.

Mike Haasl wrote:I did hear of somebody who ran a Lister 24/7.  Then it stays warm for the veggie oil, generates heat for any cogen needs nearby and is pretty fuel efficient when idling.  Not great efficiency but good.  Not sure about the emissions but if it's veggie emissions, they're probably a bit healthier for the neighborhood.

The veggie oil might need an electric heating band around the fuel line, or just a heat trace cable intended for water lines under a mobile home; but probably not even that once it's up to running temps if you keep it in an otherwise heated space.  The Lister CS 6/1 was, explicitly, designed as a ranch "lightplant" to be run off of practically whatever oil could be sourced in the early years of last century.  If you were trying to start it on straight veggie oil in the summertime, with ambient temps above 80 degrees F, starting wouldn't be particularly difficult.  The hard part is starting when everything from the engine steel to the fuel is close to freezing, but even then there are backup methods.*  The advantage that the Lister CS has is that it runs *very* slowly as compared to any modern engine, which gives the burning oil more time to burn completely before the piston is yanked away.  It's typically governed to run at 650 rpm; but as low as 450 and as high as 800rpm.  (remember, mechanical wear is an exponential function, so the slower you go the longer it runs without problems)

And I can say with personal experience that running a diesel engine off of used veggie oil will make you hungry, because the exhaust smells exactly like fresh french fries.

*Use a propane torch to pre-heat the fuel line and top of the engine block (this works better if your engine has a "heat bulb", a part for which is intended to be preheated with just such a propane torch) - or (if using an open water hopper as a cooling system) pour a pot of boiling water into the cooling hopper just before starting.

Mike, I found it, a different Mark Shepard video. It's a short passage without much for details... but that's also sort of the point he's making.
Mark Shepard at PV1, March 2014.

Mike Haasl wrote:
I'm still a bit unclear about Question #9.  Can the generator feed juice onto my household grid at a distant subpanel and then the inverter and batteries could be 100 yards away in the house?  Or do I need a dedicated wire that feeds power from the generator to the inverter?

Q9 - No, you cannot normally feed the generator into your house circuitry along with the inverter output. The generator and inverter outputs are not normally connected together. The generator needs to have a dedicated wire to the inverter but it can be 100 yards away with large enough wire. The inverter output will feed a sub-panel with priority loads if you are grid-tied or your main panel if you are off grid. This will allow the inverter/charger to charge the batteries and feed through power to your loads on the inverter output. It also allows the inverter to seamlessly switch your loads from the inverter output to the generator and vice-versa.

My inverter decides what power source is available and uses it to feed the priority loads on the inverter output. If there is grid power, it can feed it through and also charge batteries if needed. The same if generator power is available. If there is no external AC power source, the inverter generates AC from the batteries and / or PV output. Locally generated power can be also sold back to the grid, but only if the grid is up. In a grid failure, your power system MUST NOT feed power back to the grid to protect any power company workers. That's why a transfer switch is required for a generator. The Schneider inverter includes the transfer switch.

You can get a better idea of wiring for a system with PV, batteries and a generator on page 134 of the Schneider XW Pro 6848 Install Guide here:

https://solar.schneider-electric.com/download/xw-pro-iec-user-documentation/?wpdmdl=10331&refresh=6211e4c8d76881645339848&ind=media-10991&filename=ML202007_XW-PRO-NA-Installation-Guide990-91228A-01_rev-A.pdf

Page 128 shows a simplified diagram of what's inside the inverter / charger if you are a glutton for punishment ;-)

Mike Haasl wrote:

Jim Webb wrote:Batteries: I'd avoid lithium batteries, not least because of fire risks.

Jim, this is a bit surprising to me.  I know phones or small batteries sometimes burst into flames but I thought the bigger packs, especially ones that aren't DIY, were safe.  I mean there are two in my wife's prius..  

The Li-Ion batteries initially used by Tesla and other EVs are based on lithium nickel manganese cobalt oxide (NMC). EVs try to make them safe, but there have been cases of EVs burning down houses. This chemistry is more risky than the lithium iron phosphate (LiFePO4) cells which are generally regarded as the safest option. There are videos of people testing LiFePO4 batteries by short circuiting them or drilling holes in them on YouTube. That said, any time you are storing 10's of kW of energy and using 250A DC circuit breakers, caution is advised. Dropping a wrench across a lead acid or LiFePO4 battery pack could certainly ruin your day, even worse if it welded itself to the terminals. It makes sense to take all necessary precautions. Commercial LiFePO4 batteries include a battery management unit to monitor cell voltage, temperature and current. They will disconnect if anything goes out of bounds. The DIY packs I built include these same protective devices.

For comparison:

LiFePO4 batteries charge with a constant current until charged while lead acid batteries charge with a decreasing current and a long absorb phase. That means your generator will run longer to recharge lead acid batteries and the longer it runs, the less efficient it gets since its output will be constantly decreasing.

For longevity, lead acid batteries should only be discharged to about 50% and must be fully recharged to 100% every 5-7 days even if they are still at 90%. LiFePO4 can be cycled from 20% to 90% for maximum life so fewer AH of capacity are required. LiFePO4 are also happy to go for long periods without being charged to 100% so if you have a string of cloudy days, they don't have to be recharged until they have been discharged.

You will also need to add distilled water to the lead acid batteries on a regular basis and provide a vent for the hydrogen generated during charging unless you pay more for AGM or Gel batteries.

So far, I am very happy with the change to LiFePO4 and would not go back to lead acid.

Scott Loren wrote:
How about putting your setup in an insulated building with a waste oil burner to heat it?

My generator is in my shop so when it runs, I get some free heat. It's not too loud and the exhaust is routed outdoors.

Mike Haasl wrote:
 And I'd want the generator closer to the house but more insulated against noise.

Years ago when helping a friend on his race car he had a 6000 watt generator at the track for use in the pits.  It was loud.  He fitted a car muffler onto the exhaust and it was significantly quieter.
When I was building my house and using a 6500 watt generator to power the air compressor for the nail gun and saws it too was loud.  I didn't do the muffler thing but I would lean a sheet of plywood against it to block the noise away from where we were working.
If it were me I would build a shed around the generator.  Not only to protect it from the weather but to contain the noise.  I would modify the exhaust and run it through a cheap but large car muffler and run it out of the shed on the side away from the house.  I think this would greatly reduce the noise and it will give you a place to store supplies and your fuel source.  In the winter months the generator will warm the shed and your fuel, in the summer months you may need a vent fan to cool off the shed if it gets too hot inside.  Insulation will keep it warmer in the winter and cooler in the summer.

M Rives wrote:My generator is in my shop so when it runs, I get some free heat. It's not too loud and the exhaust is routed outdoors.

Hmm... generator mass heater? route the exhaust pipe through a mass? a plinth that the WVO tank sits on? A bell that encloses the tank?
Could also be done for an alternate "radiator" or "heater core" for a water-cooled engine... maybe a decent reason to use a water-cooled over an air-cooled engine? WVO tank could be an indirect DHW tank hooked to engine coolant.

Mike, the Tamera solar greenhouse uses vegetable oil as the fluid, stored in an insulated tank. Lots of directions to go with this... even if solar PV isn't great, solar thermal could be enough to keep it liquid. It could be a system like in your greenhouse (parallel or replace it) store the excess heat in WVO tank. Your generator shed could be adjacent to an end wall of GH, waste generator heat, fuel oil, could be stored in the GH where it does double duty.

Possibly one less pathway to shovel in the winter? That might mean abandoning using the sub-panel/conduit you have, but if you're needing a second trench anyways, it could just be dug to the greenhouse.

M Rives wrote:Q9 - No, you cannot normally feed the generator into your house circuitry along with the inverter output. The generator and inverter outputs are not normally connected together. The generator needs to have a dedicated wire to the inverter but it can be 100 yards away with large enough wire.

Thanks M!  I think that was the crucial detail to help sort things out in my head.  

For my situation, then I think my choices are to either:

Build an extra bay on my garage (go to a 3 car garage) and have the back of that bay be an insulated room for the generator and batteries.  There's a sub panel in the garage (60A) that I could connect the output of the system to for feeding the rest of the house.

Pros	Cons
Much closer to the house	Louder at the house
Easier to get fuel to	Garage isn't built yet
Fuel storage/prep in same garage	Smaller sub panel
Easy to get equipment in/out	Heat is wasted in winter (other than helping keep the batteries warm)
	Outside temp is down to -30F, not sure what inside garage temp would be

Build an enclosure in my greenhouse for the generator and batteries.  The sub panel in there is 95A, I believe.  

Pros	Cons
Wouldn't hear from the house	Longer walk from the house
Bigger sub panel	Takes up growing space
Heat helps the greenhouse	Heat may not be at the right times
Greenhouse doesn't go below +10F	3' wide door limits size of generator
Exhaust is much farther from the house	Can only deliver fuel by vehicle during the snow-free months

Q#12: I want to say I heard that if you have a Lister engine, it can idle and be very fuel efficient.  I want to say I also heard that it will soot up if it isn't under load often enough.  Can anyone confirm that?  One potential option would be to have that style of generator and then on cold snaps, just start it up and let it idle all night to help heat the greenhouse.  Or, I guess connect it to a 6kW heater and then it would really warm up the greenhouse.  I'd love it if the generator could keep the greenhouse warm so I'd get electricity and heat from veggie oil.  Without making a veggie oil burner.  I haven't found a veggie oil burner that my insurance company would be happy with for an affordable price...

Q#13: If you're running on veggie oil and instead of changing to diesel before shutting down, what would happen if you just let it run out of fuel?  Would that sufficiently purge the veggie oil from the supply line so that you could start up on diesel without issue?  If so, I could put a set amount of fuel in the tank and let it run through a cold night and peter out on its own in the early morning.  Then I could go out there a day or two later to start it up with diesel to charge the batteries again.

Q#14: Is a 60A subpanel (and the wires that feed it) in the garage enough to become the new main for my personal energy grid?  I think my biggest load is my welder and it's in the garage now.  So it gets juice from the street via that sub.  The next biggest load is my 3hp 220v table saw out in my barn.  I suspect that draws less juice than the welder.

Thanks EVERYONE for all the great help!  I hope this helps other people as well in the future!

Q12) You could run a dummy load (electric heater) in the greenhouse. It could even be "indirect" so you heat a thermal storage fluid, rather than the air directly, and have a separate system to use that stored heat to regulate the greenhouse temperature. That way you might not have the heat runaway on you. I have had to run a propane torpedo heater in our greenhouse a couple of times due to poor delivery timing, and had it get warmer than we'd have liked due to no thermostatic controls on a simple construction heater (still better than a freeze-up).

Q13) Maybe? If you separated the WVO/diesel systems with their own filters... "run dry" is going to still leave a bit of oil in filters/sediment bowls to gel up. Even then, I think you are setup to have to prime the engine daily, where a diesel purge would keep it primed and ready. I may have missed it mentioned (haven't read closely), but does diesel fuel treatment work on WVO? to make it more cold tolerant?

Re: hauling fuel,how will you receive the WVO? A bulk container? in the cooking oil containers? It might be easy to pull them in a sled in the winter. Other considerations: filtering/settling of sediment/water/food bits; and dealing with all the cooking oil containers if that's the delivery method.
Maybe you can have a station in the garage for loading/unloading/processing/waste and only carry small amounts of good stuff to the fuel tank.
The "fun part" about designing the engine/generator/charging/battery system aside, this is the part that will mean the success or failure of the project in the long term (or very, very quickly). You or the missus will become fed up with it all if this goes wrong.

Thanks Kenneth!  The greenhouse is pretty big so I don't think I could overheat it with this little generator and 6kw of heat.  I'd have to see if the extra fuel consumption of making heat is within my supply constraints.  But I think it is.

Processing the WVO (waste veggie oil) in the garage or up by the house is the plan.  Lugging fuel to the greenhouse with a sled is quite doable with the same gear I use to lug buckets of sap around the woods in late winter.

Your points about the veggie oil in the filters/bowls is what I was worrying about too.  Good to know...

My current available source is 55 gallon drums behind a restaurant.  I'd have to scoop or pump it into my own containers.  Unless I get them to save the jugs it comes in.  I might want to filter and store the oil in the generator room so that its thermal mass helps keep the batteries warm.  So that's a given for the garage arrangement and a con or challenge for the greenhouse arrangement.

Jim Webb wrote:

On an off-grid system, you won't want to use your precious power to heat the engine house or the fuel lines. You will need to insulate the engine house well (not forgetting to allow for ventilation) and the insulation will help to deaden the noise enough to move it closer to the house.

Would it work to have an earth-sheltered or underground engine house? That would mitigate some of the temperature problems.

(Assuming, of course, that it has enough ventilation. Maybe even a heat-exchanger or heat recovery system in the ventilation shaft?)

Hi Mike,

Q14: Will a 60A panel and existing wiring be adequate?

Perhaps? It depends on your loads. Looking at your greenhouse info I see you are using some electric heaters which may explain where your 18kWh/day is going. We run some items like a toaster oven, hair dryer, microwave, etc. but only for a short duration. The crock pot only comes out on sunny days. Your welder may be pushing it depending on how many amps it draws. Trying to run a plasma cutter and big air compressor is probably not a good idea. I run a 240V 3HP table saw and it works fine but it requires a huge starting surge (works fine except for the time when the belts were cold and it did not spin up - the pixies escaped from a $180 solid state battery switch on that occasion). Similarly, your well pump may pull a lot of power on startup. It's a good idea to do a load analysis where you document all your loads and how much power they draw. Then consider how many of them may be on at the same time.

A 6kW inverter will output 25A at 240V (6000W/240V=25A) or 50A at 120V (6000W/120V=50A). The Schneider manuals specify 60A breakers into and out of their 6kW inverter. Hopefully you won't use the full output of any 6kW inverter for a prolonged period of time since it will be pulling about 125A from a 48V battery bank (6000W/48V=125A). These are rough numbers since there will be some losses due to the inverter efficiency and wiring. Different inverters support different levels of surge current. The Schneider 6kW can briefly do 3x the rated power. It's also important to balance 120V loads since the inverter may not be happy providing the full 6kW at 120V.

You might find the spreadsheet linked at the top right of this page (look for the download button) along with the discussion useful:

https://diysolarforum.com/resources/system-energy-audit-and-sizing-spread-sheet.12/

I'll also attach an example system diagram from our previous home. It does not include a generator since it was grid tied. There are some notes on wiring sizes, mostly for the PV arrays since they were ground mounted some distance from the house. The inverter was maybe 30-40' from the priority load sub panel which was 60A. I also have a wiring loss calculator spreadsheet somewhere but it might prove more confusing than helpful.

The humidity in the greenhouse might not be too good for the generator. It sounds like a wofati dug in below frost depth might be just the ticket I'll also attach an interesting generator shed drawing I snipped from Hardy Diesel (I did get a water cooled diesel generator, but not from them).

Thanks M!  The missus and I talked today and I think we're both leaning towards having it in the garage addition that we still need to build.  We can put a heavily insulated room in it and keep the batteries in there as well.  

The conduit from the garage to the house is only 1" pvc so I don't think I can upgrade the subpanel wiring to 100 amps.  It's buried under cement so it would be a chore to upsize that wire run.  

Luckily my well is a small jet pump so it doesn't draw much.

We're thinking we might add solar some day on the garage (or the greenhouse) so having a system that can accept that juice would be nice.

Current dream is to have a Lister that runs quite often in the winter (crappy solar at that time).  Then in spring and fall the solar would help and the generator might be needed every few days.  Then in the summer it might not be needed at all.  Potential for the Lister to run 24/7 all winter with some electric resistance heaters in the greenhouse to give it a load from time to time.  Then we wouldn't have to start and stop it on diesel all the time.  We'd also need a battery bank that could handle maybe two days of normal usage (a week+ when we're on vacation).

Some of our usage is a plug in hybrid car...  And those damn incandescent light bulbs....

Mike Haasl wrote:Thanks M!  The missus and I talked today and I think we're both leaning towards having it in the garage addition that we still need to build.  We can put a heavily insulated room in it and keep the batteries in there as well.  

You can now get "server rack" battery packs which have built in heaters so temperature is no longer the problem LiFePo4 batteries used to have. When you attempt to charge the battery when the temperature is too low, it stops charging and uses the power to turn on the internal heaters. Once it's up to temperature the heaters turn off and it returns to charging. With good insulation and the natural inefficiencies of a battery will keep the battery warm whilst it's charging and discharging. Will Prowse has been discussing them recently on YouTube.

Q13-It is a bad practice to run a diesel dry.  Some can be catastrophically damaged, but it isn't good on any of them.  The fuel is the only lubrication and coolant for the injectors and injector pump.

Thanks!   R, I thought (but could be very wrong) that Listers were turned off by turning off the fuel supply.  For some weird reason I'm liking the idea of those, maybe it's the price and low rpms.

My background: I've been successfully running used veggie oil in my vehicle since 2015. I have visited an intentional community powered by a combination of micro-wind + solar + micro-hydro + used veggie oil backup generators for electricity. Good news: it works.

Mike Haasl wrote:I recently found a free source of 30 gallons a week of used fryer oil.  Suddenly this becomes a possibility.  I'm going to seek out a few other sources as back-ups before I spend any money on this.

30 gallons of week of used fryer oil is a lot of oil. Be sure that you can commit to collecting, transporting, storing, filtering, de-watering that much oil first. This all takes a significant amount of time, energy, and effort. I would recommend starting with small quantities at first, hone your practices, then build up to that amount.

Mike Haasl wrote:Q#3: I could find a cheaper, good, old diesel generator and try to work with it...

I'd recommend a 1980's-1990's model diesel engine. Unless the engine is / injectors are designed and purpose-built to run veggie oil, 2000+ year models tend to have smaller injector ports that atomize the fuel into smaller particulate for a more complete burn. Many of these injector ports are designed for highly viscous diesel/biodiesel and are too small for used veggie oil.

Mike Haasl wrote:Q#2: I've seen that you can make "pseudo-biodiesel" by mixing WVO and diesel (50/50), WVO and gasoline (80/20), WVO and kerosene (70/30) or WVO and pure gum turpentine (80/20).  That seems a lot better than the official way of adding methanol and lye and getting a 10% waste product of glycerin.  Has anyone run one of those mixes in a generator for lengthy periods of time with (or without) success?

It's not recommended to run veggie oil on a cold start: as the engine is cranking over - but before it begins to fire combusting strokes - veggie oil can slip past the piston rings and gum-up the engine crankcase and other parts. Best to always start an engine on dinosaur diesel or biodiesel (B100 in the summertime - B20 in the cold months), let it warm up, then introduce properly filtered and de-watered veggie oil. I have personally never mixed WVO with anything. I've only ever mixed biodiesel and dinosaur-diesel.
One way to hasten the veggie oil warm-up time so that you can switch over to veggie oil quicker may be to have the veggie oil run through a veggie-modified solar hot water heater type system before it goes into the engine.

On filtering & de-watering: save yourself a lot of time, money-in-the-long-term and headaches by investing in a gravity-fed, bowl-style "waste vegetable oil centrifuge" from the beginning. (BTW, ignore the pressurized centrifuges that are not designed for veggie oil and are much more trouble than they are worth). This will clean the particulate down so small that you will hardly ever have to replace your fuel filters. And, more importantly, it is the only sure-fire way to get all of the water out of your oil. Water does end up in the used veggie oil from the food that was in the fryer, from the rain/snow when the veggie oil dumpster lid was left open, and from the mop water that "accidentally" got thrown in veggie oil dumpster. Do not let water get into your engine and blow up your expensive injector tips. Properly dry your oil with a centrifuge.

Mike Haasl wrote:Thanks!   R, I thought (but could be very wrong) that Listers were turned off by turning off the fuel supply.  For some weird reason I'm liking the idea of those, maybe it's the price and low rpms.

All diesels shut off the fuel, but in a specific way that maintains prime and lubrication to the pump. I don't remember the specifics of a lister.