New to solar....What batteries do we need?

Hi there! I really appreciate all the info on this board!! thank you all... We are setting up an Off grid Solar system to run Indoor lightning/pumps/fans in our greenhouse...We already bought 10 230w e-19 solar panels from Sunpower...A 3000w Cotek Pure SIne wave inverter and a morningstar controller...Now we are looking for the perfect battery to finish our 24v system.Our budget is around 3000$..First we were Considering Rolls/Surrette L-16s...then we learned about how long a Forklift battery would last for around the same price....we want around 1200 Amp hours I believe.Someone posted that newbies should just start with Gold Cart Batteries...Any help is greatly appreciated... THanks!!

Why is your system 24v?

After our research we found that our system would be most efficient if ran at 24V......The question is what batteries do we need...so many options..........

I bought Interstate UL-16L 360 ah, 6v a year ago. They were available locally so at Interstate battery so that saved on shipping.

With solar it does pay to buy everything through one person who knows your systems, especially if your a newbie. Someone will have to make to thick cables or buy them.

Yo Stone wrote:We are setting up an Off grid Solar system to run Indoor lightning/pumps/fans in our greenhouse...We already bought 10 230w e-19 solar panels from Sunpower...A 3000w Cotek Pure SIne wave inverter and a morningstar controller...Now we are looking for the perfect battery to finish our 24v system.Our budget is around 3000$..First we were Considering Rolls/Surrette L-16s...then we learned about how long a Forklift battery would last for around the same price....we want around 1200 Amp hours I believe.Someone posted that newbies should just start with Gold Cart Batteries...Any help is greatly appreciated... THanks!!

If it were me, and assuming I truly needed that storage capacity (hint - are you sure you need so much?), then I would go with a forklift battery. I understand a company called GB Industrial Battery can provide a 1200 amp hour 24 volt battery for $3400 delivered in the 48 states. They will also pickup a discarded battery free of charge (being compensated with the recycle scrap value of the discarded battery, of course - which is good as you know they're going to recycle what they can since their compensation depends on it). In theory, you could have a battery delivered every 10-15 years (the expected life for such a battery in the off grid application) and have the old one carted off for recycling. I would get the dimensions of the battery you want delivered, then build a heavy duty platform with casters that will allow you cart the thing where you need it (battery would be 1500 pounds and with a 20" by 30" base, and height of 22"). Check with the company to see if they can place the battery on the cart without difficulty.

My experience is that up to eight 6 volt batteries or so in a system work great. 16 can work pretty well. Any more than that, and I wouldn't avoid it entirely, but would start looking into other options and be very careful with the cabling and to keep things clean and protected, and batteries filled and vented. That's a lot of batteries with a lot of cables with a lot of possibilities for things to degrade and wear out some of the batteries faster than others. With a huge battery bank ie more than 8-12 batteries, higher quality batteries may help making it less likely to have DOA batteries and more consistency between units. They should also all be manufactured in the same batch if possible.

The big problem with batteries is weight, so it makes sense for a lot of people to buy local in sizes they have the equipment to move. Paying shipping and renting equipment to move it adds a lot to the cost.

Also, know that if you have a big battery bank with, say 16 batteries, and it starts to go bad, you may find yourself isolating the worst or dead batteries and cutting the system down to 12 batteries for a while to get the most life out of your system. When you start to have problems, unless you take the time to individually charge and load test each battery, it can be pretty tricky figuring out which batteries are bad though, and charging batteries individually requires power when your system is down, and is a lot of work.

Marcos Buenijo wrote:

Yo Stone wrote:We are setting up an Off grid Solar system to run Indoor lightning/pumps/fans in our greenhouse...We already bought 10 230w e-19 solar panels from Sunpower...A 3000w Cotek Pure SIne wave inverter and a morningstar controller...Now we are looking for the perfect battery to finish our 24v system.Our budget is around 3000$..First we were Considering Rolls/Surrette L-16s...then we learned about how long a Forklift battery would last for around the same price....we want around 1200 Amp hours I believe.Someone posted that newbies should just start with Gold Cart Batteries...Any help is greatly appreciated... THanks!!

If it were me, and assuming I truly needed that storage capacity (hint - are you sure you need so much?), then I would go with a forklift battery. I understand a company called GB Industrial Battery can provide a 1200 amp hour 24 volt battery for $3400 delivered in the 48 states. They will also pickup a discarded battery free of charge (being compensated with the recycle scrap value of the discarded battery, of course - which is good as you know they're going to recycle what they can since their compensation depends on it). In theory, you could have a battery delivered every 10-15 years (the expected life for such a battery in the off grid application) and have the old one carted off for recycling. I would get the dimensions of the battery you want delivered, then build a heavy duty platform with casters that will allow you cart the thing where you need it (battery would be 1500 pounds and with a 20" by 30" base, and height of 22"). Check with the company to see if they can place the battery on the cart without difficulty.

Wow thanks Marcos! Looks like GB battery is the way to go....It seems like the Forklift batteries are just superior to the L-16s or Golfcart batteries....GB battery has a 7 year warranty...and iv heard they can last up to 20 years!! Does anyone else have anything to say about Forklift batteries? We would love to buy batteries that will last ovver 10 years....

Yo Stone wrote:Wow thanks Marcos! Looks like GB battery is the way to go....It seems like the Forklift batteries are just superior to the L-16s or Golfcart batteries....GB battery has a 7 year warranty...and iv heard they can last up to 20 years!! Does anyone else have anything to say about Forklift batteries? We would love to buy batteries that will last ovver 10 years....

I just wanted to ask explicitly - are you sure you need this much battery capacity? Read this if you haven't already: http://windandsunpower.com/Download/Lead%20Acid%20Battery%20Efficiency.pdf . I don't know what your loads are, but I speculate that perhaps a better system could be a smaller battery with a small backup generator. You need a backup generator anyway.

BTW, search the windsun.com forums - there are several threads on the topic of forklift batteries.

Good idea about the cart to move the golf cart battery. Typically truck delivery at most means setting it down with a drop gate, which is usually an extra charge. Then you have to get it where you want it on your own.

We actually found an 800-1000 Amp hour battery system.Do you feel that is more appropriate for our system>?

Yo Stone wrote:We actually found an 800-1000 Amp hour battery system.Do you feel that is more appropriate for our system>?

Sorry, I can't offer very specific advise without more information on your system and location. Knowing the total KWh consumption over a 24 hour period will be helpful. Also, are the loads constant or highly variable? It makes a difference if most of the electricity is consumed during the day while the array is likely producing, or if the loads are more or less constant at all times.

Your battery should never go below 50% discharge. So if you get a 2400Wh (24vx100Amp/hr)system then you should not use more than 1kWh per night

With a 2300W * 4hr avg hours of sun you are generating/using about 10kWh per day.
That would mean that you are 1/10th of your power at night, that is pretty awesome.

Overall I second the idea that you get a small generator and use it for high load things such as air conditioning, power tools/workshop.
You have most likely did this already, but I recommend that you use LED/CFL lights and laptops vs desktops, LED vs plasma TV, sun drying, etc

Where are you (at least solar day length and how long you get cloudy spells)? The number of days you want to run on reserve is really the driver for battery AH.

I also think a good generator NEEDS to be part of the system. There are times you have to equalize the batteries. I think it is much better money to spend on a good generator and fuel storage than extra batteries. You can buy a small Honda for a grand, knockoffs cheaper, set it up to run on propane if you want. You could use a home standby generator and control it from your charger. You can spend $2500 for a mil surplus diesel generator that will power a central AC system or large shop equipment (you are NOT going to weld or run most shop/construction tools from your inverter) and you can run it on veggie or biodiesel.

Preaty much we just need to know if we should go with the 800 Amp Hour refurbished Forklift battery...or 8 Surrette 530s..........which would have 800 amp hours as well.....gotta decide soon we need our system running within the week...thanks for the help everyone

I use the Aquion saltwater battery module in off-grid installs & I've looked at probably all competing products over the years. There is no apple to apple comparison on the different technologies available because they all have their specific advantages & disadvantages depending on the requirements of the particular installation. I like the Iron Edison batteries & Redflow flow batteries as well as others, but I do residential off-grid consulting so I'm helping normal homeowners say in a 2000sqft 3Br house cut their ties to the power co & do their own thing. Someone mentioned they come on a pallet & yes, that's what I normally install. The latest Aspen 48M is 30.6 kwh of storage which can easily get you through summers where you have mostly sun, but it's more efficient to parallel at least 2 or 3 of these & I'll be doing videos & articles explaining some of these issues about charge / discharge cycles on Aquion's blog & others each month besides my own YT channel at http://bransonoffgrid.com . Here is my first Aquion article just posted 11/23/2016 - http://tinyurl.com/zdt3auw & the first system I designed using the 30kwh module -    These batteries have been on the market since mid 2014, so they have a track record in large industrial settings, but few in residential just yet because they are just gaining momentum in that market. Your typical local solar installer doesn't usually embrace new technology when it first comes out no matter how good it looks. They usually wait for the commercial installers to get systems using the technology up & running; then after a few years they get feedback from these people to see if they should use it based on how the tech is working. So maybe in 2-5 years from now your local solar installer will offer Aquion, IE, & Redflow as options to Lead acid. I'm sure the Tesla Powerwall will sell a good number as well, but I just do off-grid systems & don't think Lion in any of the current formats is better than the 3 I just mentioned. Your results may vary. If you're really going to be off-grid then you should talk to someone who lives off-grid & learn from then in the same way that if I want to learn permaculture I come here to learn from people who have actually been doing it.