ALTERNATIVE ENERGY

Solar Battery Chemistry Comparison Chart | Best For Off-Grid?

best type of battery for off-grid

What is the best battery for solar storage?

Lets take a quick look at three battery chemistries. Lead acid, Lithium Iron, and Nickel Iron.

I found a nice comparison chart (below) on IronEdison.com – who specializes in Lithium Iron and Nickel Iron batteries for energy storage applications.

Which Off-Grid Battery Chemistry Costs Less?

In short, when comparing the battery chemistry type regarding the money, lead acid will cost less up front. But in the long run it will cost the MOST.

The least expensive battery chemistry for the long haul is evidently nickel iron type batteries. Though some regular maintenance is required (regular cell watering – like flooded lead acid batteries).

With that said, I really like the lithium iron battery. Although it is a bit more expensive than nickel iron, it’s a lot cheaper than the lead acid type over the long run. Best of all, there’s zero maintenance required. Ever.

The Best and the Worst

Looking at the comparison chart, the worst factors come from the lead acid battery column. Low number of lifetime cycles (~1,000 at 50% depth of discharge). And very high cost over the long run due to having to replace the battery bank comparatively often.

Some of the best factors come from lithium iron AND nickel iron.

Lithium iron batteries require NO MAINTENANCE. This can be a huge factor. There’s also no venting or off-gassing. Therefore no special battery room requirements in this regard.

Nickel iron batteries have a very high cycle lifetime. Up to 30 years (11,000 cycles) at 50% depth of discharge.

Iron Edison Battery Comparison Chart

solar power battery chemistry comparison

The Takeaway

5 – 7 Years

Lead acid type batteries may be good for relatively short term battery storage applications (several years, or maybe up to 5-7 if you’re careful with the battery bank and use low depth of discharge every day). But then you will have to dispose of that bank and replace all the batteries if you want to keep the system going…

Cha-Ching goes the cash register. (Remember when they used to make that noise? – showing your age…)

10 – 15 Years

When you’re considering 10 – 15 years for an off-grid battery storage, then Lithium iron would be my personal preference.

Why? Because I wouldn’t have to deal with changing out a HEAVY battery bank in 5-7 years. And they’re maintenance free (and lighter, less space requirements).

20 – 30 years

The nickel iron battery chemistry will cycle up to 30 years @ 50% DOD. And this type of battery storage will be the least expensive over that period of time.

However there is regular maintenance required. That may be fine for some people. But maybe not for others. If it were me, and I could afford the extra for Lithium Iron, that’s what I would do. Not because I can’t do the maintenance, but the peace of mind not having to remember doing it all the time ;)

Hopefully this will help someone who may be searching the internet for such a battery comparison chart.

Note: IronEdison.com is a sponsor on this site. They distribute the batteries mentioned above, and are located in Colorado. Give them a call or send an email if you have any questions about batteries!

Continue reading: 8 Advantages of Lithium Iron Batteries for Off-Grid Energy

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21 Comments

  1. A question for you Ken.

    I noticed the lithium iron performs poorly/life-cycle (compared to the nickel iron) when it comes to the 80% discharge rate.

    I also understand the convenience of not doing “maintenance” of the Batteries, but the life cycle from 50% to 80% discharge rate is no difference on the Nickle Iron where it’s less than 1/2 on the lithium. Also the total life cycle is double for the nickel over the lithium.

    So here is the question, is a monthly check on the Bat Bank (and a electrolyte change at 10 years) and 30% more useable charge not lean itself to the nickel iron bats?
    Plus the possibility of “permanent damage” that ‘may’ occur if charger below -4 on the lithium not worth the nickel iron batteries? And yes I understand the Lithium can be installed inside, but…..

    1. All good questions.
      Next I might do a cost comparison between reasonably USABLE AmpHours (Watt hours) after factoring in depth of discharge for reasonable longevity of each battery type. This would better compare apples to apples.

      But the short answer for you is, yes, it leans itself towards nickel iron for the very long haul. Provided that there will always be a household member on premises who is able to do the maintenance as required.

      You would also have to factor in the cost of the 10-year electrolyte replacement, which frankly, I don’t know at this time. Sounds like something worth asking the folks at Iron Edison about…

      If I were replacing my existing battery bank, I would be keeping the batteries inside (as they are now). So temperature wouldn’t be an issue. Even if I had to box off part of the existing room to accommodate venting, I would still keep them inside.

      Like I said earlier, if I could afford the Lithium Iron route, that’s what I would likely explore. However if solely deciding on cost, and assuming I’ll still be at the location for 20-30 years, I would consider the nickel iron for sure.

      But given the way property taxes are rising, who knows where I’ll be 10 years from now! (just got my tax bill today) :(

      1. Ken;
        Another thought…
        Was yacking with my brother about used tesla battery.
        He happens to own a Tesla (Californian ya know) and was talking of the Used T Batteries.
        Any Thoughts?

        1. How interesting. All I know is Tesla uses Lithium ion technology in their battery pack modules underneath the vehicle. Each module contains lots of individual batteries and a cooling system. It’s probably impossible to discover their specifications. And if the batteries are “used”, one wonders how used? Still interesting nonetheless…

          1. A quick Wikipedia Search….

            Ok, now we’re having fun…
            A few interesting facts on the T Battery.

            The 85 kWh battery pack weighs 1,200 lb (540 kg) and contains 7,104 lithium-ion battery cells in 16 modules wired in series (14 in the flat section and two stacked on the front). Each module contains 6 groups of 74 cells wired in parallel; the 6 groups are then wired in series within the module. As of June 2012, the battery pack used modified Panasonic cells with nickel-cobalt-aluminum cathodes. Each cell was of the 18650 form factor (i.e., an 18 mm diameter, 65 mm height cylinder), similar to the Panasonic NCR18650B cell that has an energy density of 265 Wh/kg.

            The P90D (car) combines a front axle power of 259 horsepower (193 kW) and rear axle power of 503 horsepower (375 kW) for a 0–60 mph time of 2.8 seconds.
            762 HP Holy COW!!!! That’s a LOT of electrical power in a very short time.

            In January 2019, Tesla discontinued the 75 kWh battery option, leaving two possible configurations with the 100 kWh battery pack.

            My understanding the newer battery packs has an estimated millage rating of over 1 million miles and unlimited time-frame.

            Are we having fun yet, 0 to 60 in 2.8 seconds, in an electric car WOW!!!!!!

          2. NRP,
            Wow! I had no idea. 0 to 60 in 2.8 seconds. That’s fast for any car, especially for one you are riding on a battery!

          3. Ken:
            Further in the info it stated a “G” fource of 1.1….
            I have got to borrow his car someday 😁

  2. Ken,
    Thanks for the research on solar batteries. Definitely some good information to store back for when the time comes to move into that level of preparedness. I may not be ready for a whole home solar system but, I am wanting to buy a small solar system. I’m looking for something just to power some camp LED lights, charge up batteries, and maybe run some 12 volt gadgets. I have looked at some places and trying to compare the best I can. Do you or any of the MSB community have any recommendations on what to get (under $300.00). I really appreciate all the info that I have found on this site!

    1. That sounds like an interesting article topic(s). Small solar power systems for “x” amount of $$. Food for thought. Thanks.

      I can’t answer your question in a short period of time in a comment thread (due to the caveats, what-if’s, and variables of use-case scenarios, and requirements. But, I will put something like this in the Que for another article.

    2. – Prepper Dan,
      I have a small system similar to what you are asking about. I managed to get two John Deere marine-type 105 ampere batteries used for the core charge price ($20 @ each), a 60-Watt solar panel (yes, I know I once reported it as a 40-Watt. I’ve had it out of the Faraday cage since then.) on clearance for $50; the panel came with a 10-amp charge controller and basic wiring. I added two RV/boat type battery boxes for another $15 from China-mart and made my own cables from 2 clamp-on ends and cutting the longest replacement battery cable I could find from the farm-and-ranch store in half. That cost another $10.
      I can run 12 volts @ 50 amps for 14 hours without any power in; It will recharge nicely in 6 hours of sunlight. I can hook an inverter across the two and pull as much as 1500 watts for about 30 minutes for my chainsaw. (Done very, very cautiously the first time.) I loaded the batteries and inverter in my yard wagon.
      For the small amount I have in it, I felt that was pretty decent.
      – Papa S.

      1. Papa Smurf,
        That sounds like an awesome little system there. I will have to research the supplies in my area. 1500 watts for 30 minutes? I smell a pot of coffee brewing! I’m liking your idea a lot now! Thanks!

      2. Be careful with your numbers.

        12 volts @ 15 amps for 14 hours = 210 amp hours (AH)

        If you’re using two 105 AH batteries, and you draw them down to zero (which you would in this example), you’ve just toasted them. Never do that to lead acid batteries.

        It’s advisable to not go below 50% depth of discharge (DOD). And advisable to limit DOD to 30% for significantly better cycle life. Just saying, for the sake of others reading this.

        1. Thanks Ken! I don’t really have a firm understanding of the numbers and calculations of electricity yet. I haven’t had the time to study it. I may need something easier that I can just setup that has a plug and play function design. May have to stick with making my coffee the old cowboy way when camping.

  3. The controller is the most important part of the system. This greatly improved battery life while delivering consistent results.

    Even batteries that aren’t used much decay with time.

    You can sometimes find deals on batteries from commercial equipment.

  4. Are other battery chemistries susceptible to Coup de Fouet? This is a condition after extended periods of long float charge (years) the discharge voltage drops then later recovers under initial heavy current load causing your inverter to drop out on low voltage. Just when you need it, nothing is there to push the load.

  5. Am I reading this correctly? It looks like Iron Edison’s chart compared the Nickel Iron and Lead Acid costs for thirty years, but the Lithium Iron for fifteen years. To make a correct comparison, doesn’t that double the cost of the Lithium Iron, as you would have to buy it twice, putting it at about $3 a watt-hour (red box)?

    1. Wendy, I believe it was all factored in. If you’re serious about doing your own due-diligence, you might give them a call.

  6. Store your Lipo4 bat at 40% charge, charge to full and discharge back to 40% every 6 months to avoid the storage effect. You should discharge down to about 20% infrequently and check if they need to be bottom balanced. Lifespan is also determined by DOD when in use, which decreases rapidly with frequent DOD beyond 40%.

  7. You did not mention AGM Batteries. Do they have performance any better than the flooded lead acid type?

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