In my years of experience living off the grid (since the late '90s), I have found batteries to be the most expensive and troublesome component of a renewable energy system over the long run. With that in mind, I knew there must be a better solution than the standard "go-to" batteries such as Trojan L-16's and T-105's or even the high-end Surrette or super high-end Solar One batteries. While high-end batteries often work very well, they are quite expensive. So for years, I have kept my eyes open for a better solution. And I finally found it!
When our small bank of Trojan L-16's bit the dust, we had been hearing rumblings of another option from friends. It was relatively inexpensive, often available locally, and was incredibly heavy-duty and long lasting. We decided to try it out, and so far our experience has confirmed what many others have been experiencing.
You may be thinking of new technologies involving sealed batteries of different materials, but from what I have seen, the prices are still too high for these units. What I would call your attention to is still the standard lead-acid deep cycle battery, but one of a different variety. They are sometimes right under our nose and for some reason we don't even think of them as an option. What could this possibly be?
The lowly forklift or industrial battery used in electric forklifts or pallet-jacks. It is simply an incredibly heavy-duty, incredibly large, and surprisingly cost effective lead-acid deep cycle battery. Forklift batteries come in a variety of voltages (12, 24, 36, or 48) and sizes (from 1,000 pounds to several thousand pounds). They are available at local industrial battery suppliers or in at least one situation, from the manufacturer.
The lead plates on a forklift battery are far thicker and should last much longer than any L-16 battery made for renewable energy. The battery is composed of 2 volt cells, all packed in a heavy-duty metal case and tied together with metal bars in the proper configuration to add up to the labeled voltage. When used with a forklift every day, these batteries typically last no more than seven or eight years, but expected life-span is up to 15 or 20+ years when used with a renewable energy system, properly maintained, and not deeply discharged.
Lifetime Battery Cost Comparison Chart
Cost
This is the "zinger" for me. Let's take an example. Say you would normally need 8 Trojan L-16 batteries (this is not to indicate that 8 would be sufficient for you, this is simply an illustration). At $300-400 per battery, we will take an average of $350 x 8 batteries = $2,800. This would be around 740 amp-hours of batteries at 24 volts. Now let's take a forklift battery that we have experience with--GB Industrial Batteries. There are a variety of sizes but let's take the 24 volt battery that is 804 amp-hours and weighs almost 1,100 pounds. A little larger than those 8 L-16's. How much does it cost? Expect to pay around $2,500. Now, bear in mind that this battery should last at least twice as long as those L-16's if properly cared for. That is what I call a good deal!
Where to Buy?
Forklift batteries are readily available from industrial battery dealers in most large cities. And while it is certainly worth checking those local sources, it is very possible that your best deal may come from an out-of-town source.
In addition, anytime you buy a battery for off grid purposes from a forklift dealer, you have to expect that the dealer won't be much help. They may be very well versed in forklift batteries for use in forklifts, but we have found them to not only be clueless about off grid usage, but to actually give information that is just plain inaccurate. You see, what may be good advice for a forklift user could be positively bad advice for an off grid user. We use our batteries VERY differently. While a forklift user will most likely wear their battery out in 7 or 8 years by wearing the plates out, an off grid user can get over 15 years and the battery will likely succomb from sulfation rather than the plates wearing out. What this means is that the way you use and maintain an off grid battery must necessarily be much different than the way you operate a battery on a forklift.
With that said, I recommend looking at the few off grid dealers who carry forklift batteries and give them a call. You'll not only get the longevity and economy of a forklift battery, but you'll also get the support of an off grid dealer (very important unless you are an experienced off grid user). Off grid retailers that carry these batteries are hard to come by but a couple sources come to mind. Quality To Last (they carry the good and affordable GB Industrial Battery) and Stoves & More (they also carry GB). Neither of these sources have the mentioned battery on their website, so you'll have to give them a call or send them an email.
The other option is to purchase straight from a manufacturer or local industrial battery dealer, with the most economical one being GB Industrial Batteries. Just remember, please don't take their advice for usage and maintenance when used as an off grid battery...they are likely to totally confuse you as they have others. Seek advice from someone very familiar with off grid battery use.
How Do You Move A 1,000+ Pound Battery?
The only drawback I am aware of when purchasing a forklift battery for use off grid, is the logistics of picking up and installing such a large heavy battery. This can certainly be done if you have a tractor with a front loader to unload it.
But here is a tidbit that should be very helpful. It is possible to order the 12 volt GB Industrial Batteries with removable cells. That means that a 600 pound battery could be temporarily broken down into 100 pound pieces. It costs extra to do this, but could be well worth it if you have a difficult location to install the battery in. And if you system voltage is 24 or 48 volts (for most people it should be), you can wire 2 of the 12 volt batteries in series to make 24 volts or you can get up to 48 volts with 4 batteries wired in series.
Oh, and by the way, learn from our mistakes...don't put your battery room in the middle of your house! Put it in a location that is easily accessed from outside.
Lower Cost Alternative
Still too expensive? Try a lightly used forklift battery. I usually do NOT recommend used batteries as they could have been damaged by abuse, but if I had to buy a used battery, these forklift batteries are so heavy-duty that they can withstand some abuse. Don't expect to get 20 years of service from a used battery, but I have found a good used forklift battery to run around $500 and even if it only lasts 5 or 10 years, it is still a good deal. If you go that route, make certain you know your "stuff" to check out. Check all cells with a volt meter and hydrometer (to check specific gravity). You are looking for any dead cells (much lower voltage or specific gravity than the rest of the cells. You are also looking to see that the specific gravity looks good when fully charged as this is an indicator of the battery's health. I have heard of guys buying a 36 volt battery so they can eliminate all dead cells and combine all good ones to hopefully add up to 24 volts.
More Info?
Looking for more details on batteries in general or forklift batteries in particular?
Off Grid Boot Camp is our full training course that contains an entire module to help you choose the right batteries, the right number of batteries, use them efficiently, and maintain them for long life.
Members may access the lesson titled "Specific Batteries" (it's just one of 15 lessons in the "Batteries" module). You'll learn all you need to know about batteries and more!
21 Comments
Ron Ortiz
April 23, 2017What about Tesla's Powerwall? Those are basically glorified laptop batteries, which can be drained down to zero and charged back up without any major issues. Have you had any experience with those?
Nick Meissner
April 23, 2017Hi Ron, No first-hand experience, and I'm not motivated to experiment with them after crunching the numbers looking at lifetime cost compared to something like a forklift battery.
Technologies like the Powerwall do have advantages, but they also have disadvantages. One huge disadvantage is the lack of choices when it comes to components that will interface with the Powerwall. They operate at a MUCH higher voltage than regular off grid equipment is built to handle, so you were stuck with I think a couple of very limited options for inverters, and those were built for grid tie systems (not off grid). Now as I understand it, the latest version has a built in inverter, which means you have no choice at all. Either you like the package or it's too bad. And remember, this is build with a grid tie system in mind. So if that is the route you are going to go, then it could be an option, but not if you want to go off the grid. And I don't know about you, but I get nervous when a company tries to eliminate my options and give themselves a monopoly rather than expand my options and give me a piece of equipment that plays well with the other standard equipment in the industry. Just my 2 pennies worth :-).
Ron Ortiz
April 23, 2017Thanks for the quick response and information!
Richard Crucet
April 23, 2017Great informaction, thank you.
Tim Day
April 23, 2017I know they're expensive to start with but would a nickle iron battery pay for it's self.
Nick Meissner
April 23, 2017Hi Tim, The Nickel Iron batteries are reported to have a long lifespan (although there is some discussion about how long that lifespan is), but like you mention, they are exceedingly expensive.
Numbers are funny things...they aren't as black and white as you would think. The Nickel Iron battery companies will give numbers to show you how much less expensive their batteries are over a lifetime, but when I run the numbers, I come up with a different picture. So I'm open to someone correcting me, but here's an example. Nickel iron says 3600 cycles at 80% depth of discharge. GB Forklift says 1,500 cycles at 80% depth of discharge. So if that is correct (and there is debate about whether Nickel Iron will yield as many cycles as claimed), then you are looking at a little over twice the lifespan. Sounds good. But when you factor price in, it takes a nosedive. Let's take an 800AH battery bank at 24 volts. Cost is roughly $2500-3,000 for a GB forklift battery. For Nickel Iron, you are looking at $13,000-15,000!!! Roughly 5 times the cost for a little over twice the lifespan. Not good.
So it depends. If you have the money to blow and want a battery that will last the absolute longest, then Nickel Iron may be just the thing for you. But if you are looking for the lowest lifetime cost, I still say the good old lead acid forklift battery is the best deal.
A couple other factors...I understand that the efficiency of Nickel Iron batteries is not as good as lead acid (lead acid is typically 80% efficient and numbers that I have heard about Nickel Iron range from 50% to 70%) meaning that you do not get as much power out of them as you put into them. I also understand that the voltage swings when you put Nickel Iron under load are more extreme than with Lead Acid, which could be a challenge when your batteries are running low and a large load comes on.
Michael J
April 23, 2017Nick,
How about using a forklift with a home grid tied battery bank?
Currently I have 4x 6 Volt golf cart batteries that I keep connected 24x7x365 to a large Schumacher computer controlled charger. During a power outage I can pull from them. They were very useful during the N. Idaho Nov 2015 windstorm with no power for 6 days. I recharge them with my gas geni while I use heavy draw appliances.
I could envision using a forklift battery charger to keep the batteries topped off until needed.
I got the idea from here: http://www.battery1234.com
Thank you.
Nick Meissner
April 23, 2017Hi Michael, You could use a forklift battery charger, but they are built for charging up a massive battery as quickly as possible before the next shift starts, which can be hard on the battery. There may be some that are gentler, but I would be careful about this. I would suggest using the charger that is built into high quality inverter/chargers. The inverter/charger will typically be gentler on your battery ( 3 stage charging which backs off charger power as the battery is more fully charged) and has many features built specifically for use in home power systems (Magnum even has a "Battery Saver" charge function for folks who have grid power and want to keep their batteries topped off). So yes, the forklift battery charger could work as long as it is sized properly (not too larger for the size of battery bank) and at least has a 3-stage charger, but it is not ideal.
Joe Patricia
April 24, 2017Hi Nick
How is the family? I have forklift batteries 1726 amp hours. What do you mean by discharge too low? Do you mean by percentage or volts?
Joe
Nick Meissner
April 24, 2017Hi Joe, Good to hear from you! The most accurate method for determining the battery's state of charge is to check the specific gravity of the battery acid with a hydrometer (my favorite is the HydroVolt meter). Unfortunately, checking the specific gravity is also the most time consuming method, so most folks only do that at then very beginning of their off grid career (when getting used to everything) and also if they ever have any issues going on and are uncertain as to how their batteries stand.
Checking the voltage of your battery bank can be accurate or very inaccurate, depending on the circumstances. The only time that voltage is accurate is if there has been little to no charging or discharging for several hours (i.e. the battery has been idle). In most homes, this is not practical because the fridge and freezer are turning on and off periodically, but if you check first thing in the morning before the sun is hitting the panels and before anything major has turned on, you should be able to get a rough idea of how things are looking.
The other method for checking battery state of charge is to use a state of charge meter (for instance the TriMetric meter or the state of charge meter that comes extra with Magnum, Outback, or Schneider inverters). These types of meters are initially programmed with the size of your battery bank, then they keep track of how much power is going in and coming out of the batteries and do simple math to determine the percentage of charge that is left. Every time you fully charge the batteries, the meter is reset. While this type of meter is very handy, it also has a lot of room for inaccuracy as you get further from the last full charge, as there are all sorts of inefficiencies that it's impossible for the meter to keep tabs on. So as long as you're batteries are living up to their capacity rating AND as long as your batteries were fully charged (thus resetting the meter) within the last several days (or week maximum), then it should be relatively accurate. And if it's the middle of the days where your solar is charging or you are discharging (making your voltage reading inaccurate) then this type of meter is your only choice (short of checking the specific gravity). If you are familiar with aviation instruments, think of the state of charge meter as your gyro compass and voltage as your magnetic compass. When experiencing turbulence, the gyro compass is far better than a magnetic compass (which is bouncing around), but the longer you go from the last reset, the less accurate your gyro is.
Anyhow, I hope this helps. Feel free to comment back if you have any further questions. Take care!
Randolph
April 24, 2017I see that you address the lift truck battery but I don't see it doubled up.Is there cause to think that one will suffice in an off grid environment. With a 1000 hour battery and only able to utilize approximately half those hours.what might your though be.
Nick Meissner
April 24, 2017Hi Randolph, With a forklift battery, it is basically a metal enclosure that contains a bunch of large 2 volt cells. Forklift batteries can come in a variety of voltages "out of the box"--12 volts, 24 volts, 36, volts, 48 volts. So you'd have to look at what your power system requires and if you need more than one battery, you can certainly double them up (by wiring them in parallel). If your power system is 24 volts or 48 volts you also have the option of wiring two batteries in series (i.e. two 12 volt batteries wired in series make 24 volts, or two 24 volt batteries wired in series make 48 volts). One advantage of going with two smaller batteries rather than one enormous one, is that a smaller/lighter battery is easier to handle and move around.
Joyce
April 26, 2017Gosh, this sounded like a great idea until I thought about what do I do with a used up forklift battery? seriously it's not like I can call "Batteries R Us" to deliever a new forklift battery and haul the old one away. What do people do with these things when they die? Also it seems that it would need to be placed on reinforced concrete as it is half the weight of a car. The price is no problem, but where do you put something that big and heavy without causing damage? Assuming I had a neighbor with a frontloader/tractor.....how are these folklift batteries delievered when you order one? Sorry to ask such dumb questions but I can't wrap my head around all the practical aspects of actually getting the battery in place and to a recycling center when it's finished.
Nick Meissner
April 29, 2017Hi Joyce,
There is no such thing as a dumb question! And you brought up some good points that others might be wondering about too.
First, if you purchase the proper size and take care of a forklift battery, it should last for many years. I hear of folks getting 15+ years out of them (once again, assuming the proper size and maintenance). But there is still the question of how to move the battery either when installing it or replacing it. I'll try and address that below.
The battery will come via freight truck, and while they do offer liftgate service, we opted to pick it up at the freight terminal in our nearest large city. Out battery was just fine in a 3/4 ton pickup truck, but it all depends on which size you go with as some of these forklift batteries are massive and would be difficult to deal with. For that reason, I recommend going with one (or multiples) of the smaller sizes.
Whatever batteries you go with (whether forklift or otherwise), it is advisable to place your "power room" in a location that is easily accessible from the outside, so you could get as close as possible with (as you mentioned) your neighbors tractor. I speak from the School of Hard nocks as we didn't think of that years ago when placing the power room in our first power system and had to get the forklift battery into the middle of the house! We did it, but it would have been a lot easier if we had thought ahead when placing the power room. If your situation is such that this is impossible, then one option is to order 2 (or more) of the 12 volt batteries which can be special ordered with removable cells. In a 12 volt battery, there would be 6 cell, so you can divide the overall weight of the battery by 6 to get an idea of the weight of the individual cells. That opens up a lot of options. Some things that we found helpful in moving the battery are a heavy duty come-a-long and short sections of steel pipe (for rolling the battery on the floor into place). You'd be amazed how easily a 1,200 pound battery rolls on those steel pipes on a hard floor! A cherry picker or something similar could also be useful for lifting it off the truck if a neighbor's tractor was unavailable.
As far as the structure of the floor, it all depends on the construction of your home. If your floor has a crawlspace under it (where wood floor joists are supporting the floor), then it's always a good idea to put a block or concrete pier under the floor where any heavy objects will be (this could even include a wood stove). It's not a big job. Of course, a concrete floor is the easiest and strongest if you have that available.
And finally, remember that this is not an operation you'll be doing every year, or every 5 years or even every 10 years. This is something that should only have to be done every 15+ years if you size it properly and maintain it well. Once it's done, it's done for a long time!
I hope that helps. Take care!
Rick
November 29, 2017I am looking to purchase solar panels to power entire house.I Live here in Sunny Florida. I've had 3 different companies give me estimates, and the lowest unit was a 10.2 based on my electricity usage. Any good info or companies you can point me towards?
David S.
December 24, 2018Goodmorning Nick,
I've purchased some property with the infastrucre foe a peloton wheel. Why can't I build or purchsde a water wheel that 120 or 240 volt system, and forget about the baterries all together. My flow is 24/7, when I need it on my vacation property.
David S.
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