Best Nickel Iron Battery

Nickel Iron Battery Off Grid Energy Storage | Last One You’ll Ever Need

Best Nickel Iron Battery

The Nickel Iron battery from Iron Edison of Denver, Colorado, is an updated version of Thomas Edison’s battery design that he considered to be nearly perfect.

For Off-Grid energy storage and renewable energy systems, this battery will likely be the last one you’ll ever buy. Why? Because it’s nearly indestructible and lasts up to 30 years!

(UPDATED 2019) COST ANALYSIS (further down the page)

Edison’s battery recipe used iron oxide and nickel hydrate, without the corrosive acid-based electrolyte used in today’s lead acid batteries.

The result was the long life Nickel-Iron-Alkaline cell.

The Nickel Iron battery features the longest life span of any battery ever invented.
You might want to read that again…

Advantages | Specs

  • Rated for 11,000 cycles, or 30 years of daily discharge!
  • Completely resistant to freezing.
  • Operating temperature range of -22 to +140F (-30 to +60C)
  • Tolerant to overcharge & over-discharge.
  • Supports 80% depth of discharge.
  • Discharging a Nickel Iron battery 80% or more will not negatively impact its life expectancy .
  • Daily deep discharging has no impact on battery cycle life.
  • Fully compatible with industry leading inverters and charge controllers like Schneider, Outback Power, Magnum Energy, MidNite Solar and SMA, just to name a few.
  • Available in 12, 24, and 48 Volt configurations.
  • Retains ~ 88% of capacity at 32 °F whereas lead acid is typically significantly worse.
  • Capacity is ~ 118% of rated at 68 °F whereas lead acid 100% capacity is typically at a higher temperature.

Iron Edison is the only company to have tested the Nickel Iron battery at National Renewable Energy Laboratory in Golden, CO. Tests confirm that the cells over-perform at the 5, 10 and 20 hour discharge rates by nearly 20%!


– They may require water every 1 – 3 months.

– Electrolyte replacement every 10 years for optimal performance and energy capacity.

– They do have some hydrogen off-gassing and require a ventilated area.

They are ideal for Off-Grid applications where they stay healthy in a constant-charging environment that would be destructive to other battery types.

Nickel Iron Battery Price

For those who are serious about Off-Grid systems, a cost analysis over an extended operational time will prove that they outperform.

The initial outlay will be higher than lead acid batteries. But, wait, check out this “back of the envelope” cost analysis:


200 AH, 48V Nickel Iron battery ($9295)
9600 Watt Hours (7.68 kWh usable at 80% discharge)
Cost per year over 30 years = $309/yr.
Cost per day over 30 years = 85 cents
$0.85/7.68kWh = 11 cents per kWh!

That figure likely translates similarly even with other capacity sizes.

Replacement Costs?

Again, they will likely be the last battery you’ll every buy. Unlike a lead acid battery bank.

Nickel Iron will last ~ 30 years while lead acid batteries only ~ 5-7 years.

That means your replacement cost analysis of lead acid batteries should be multiplied 4 to 6 times in comparison over the lifetime of a nickel iron battery bank.

Usable Capacity

But there’s another cost factor to compare: Capacity!

The Nickel Iron battery far outperforms regarding usable capacity (80% usable) while lead acid should NOT be discharged beyond 50% and recommended to only discharge 30% for longest life.

That’s a BIG difference when you’re factoring in cost (the number of batteries you’ll need to achieve a given capacity). | Leading Supplier of Nickel Iron Batteries in North America

So after factoring both (replacement costs and capacity needs), this battery type might be a good choice for your Off-Grid energy storage.

Brandon over at will gladly answer ANY of your questions about this or any other alternative energy needs. They’re located in the Denver area and will be glad to help.

They also have Lithium Iron batteries, but that will be another post…

Iron Edison

Continue reading: Lithium Iron Battery For Solar Off-Grid Alternative Energy Systems

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  1. I heard about these on a podcast the other day. Sounds intriguing. Now if I could only convince the wife…

    1. They’re definitely worth considering for those who are designing a long term off-grid energy storage. Hopefully this will help those who may come across this article while doing a search for nickel iron batteries.

      I will also be posting on their other battery type, Lithium Iron. It has it’s own unique advantages too. Maintenance free. However I don’t mind doing battery maintenance…

      The key is, when designing a system from scratch, you should look at all the possibilities that you can think of before making a purchase decision. There are a number of battery types to choose from and they each offer their own pros and cons…

      When it comes time for me to replace my current battery bank, this will be one of the types that I will consider.

      1. red,
        If you’re in it for the long haul, you can’t beat 11 cents per kilowatt hour. “Overpriced” is relative to one’s usage expectations.

        1. Still overpriced for the avg working man. This is for Rich people not the every day Joe.

          1. Joseph,
            I wouldn’t say that it’s overpriced. Rather, it is within the range of what one would pay (anywhere) for energy storage of this magnitude / specifications.

            No one said that storing energy is cheap. That’s why most all homes are wired to the electrical power grid.

            Off-Grid energy systems are unique to those who build further than a cost-threshold distance of what it would cost to connect to the grid. And it’s unique to those who simply want to be Off-Grid for various reasons.

            There are LOTS of variables when it comes to sizing a system or choosing a type of battery technology to use – which ultimately affect the overall cost.

            And you’re right. Not every one can afford to do this.

            Also, one’s definition of rich will vary quite widely. Some people think that a “working man” earning $50K is rich. While others don’t consider rich unless a man is working for $100K. Still others have different opinions. But I digress…

          2. Joseph,

            Matter of perspective. Know lot’s of work-a-day Joe’s who own high dollar fishing or ski rigs that would say the same thing you said. It’s a matter of needs, goals, and possibly, necessity.

            For what it’s worth, I don’t plan on making that expenditure either. Price has something to do with it, but I see nothing to be gained by dividing by class, wealth, and financial capabilities. If such a system is someone’s goal, if it fits their budget (easily or by struggling), go for it. I commend them for their accomplishment.

            Most folks that are preppers have to make some sacrifices to achieve their goals. Some goals require greater sacrifice. This system may be exactly the one some are looking for and willing to make the sacrifice to attain.

          3. If it was affordable for the avg working man, we wouldn’t need power plants.

  2. Ken
    Is there any difference in the type of batteries regarding the holding of a charge over time – we get periods of weeks with little sun. I am reluctant to have a grid tie-in or the running of a generator frequently. I would consider this system to be a back-up for grid down emergencies, not a daily contributor to my electrical usage. Just thinking long term.

    1. Holding a charge over time isn’t the best way to think about the battery situation while not in use.

      Rather, keeping the batteries ‘floating’ or trickle charged will assure that they stay healthy.

      By having a battery bank in the first place will presume that there’s a means to charge it. And that charger should also have the ability to ‘float’ the batteries.

      That said, generally speaking, a fully charged battery bank will self discharge over time, but it would take quite some time to become a big problem.

      For example my current battery type spec sheet indicates a self discharge less than 3% per month. So if I never used them, I would want to recharge them fully within a year. Might be a good rule of thumb for healthy batteries when not in use.

      1. Ken
        Thanks. With only three or four days of direct sun in a month, Oct to Mar, there would probably be enough to keep the batteries healthy. But, i’m still mulling over the investment for this location.

        1. Solar isn’t for everybody. With only three or four days a month of sun, I would think it’s not for you.

  3. Ken, a question. Some 10-12 years ago, I had a conversation with a gentleman whose solar panel array behind his home had caught my attention. It was large, very large. As I recall, 50 kw. He was wealthy, at least for our part of the country. He told me, if I remember correctly, that the total installed cost was around $50,000. He went on to explain that approximately half that cost would be recovered through tax credits and the rest should be covered by the electricity he would sell back to the grid. Since his system was grid tied, I’m not sure he had battery back up. If not, the systems available from the source you linked are actually pretty reasonable in price, since they include these clearly superior battery bank. Now my question; are these tax credits still available, and if so, does that apply to non-grid tied systems?

    1. Dennis
      My 2¢, end of last year I did check on the Fed Tax Credits (30% of the cost of the total system, including Labor), and yes they were still in place even though some had pushed to stop them, now for the new 2018 Tax, I have not checked, but I have not heard of them going away. I did understand the credits were extended for approx. 10 years.

    2. Regarding the tax credit, they are still available. And it doesn’t matter if grid tied or not.

      I used Form 5695 when I took mine. I received 30% credit on my taxes on what I had spent for my system.

      I found this regarding the phase out of the solar investment tax credit (ITC),

      The credit will be phased out gradually between 2016 and 2023. The claimable amount will remain at 30% for all systems on which construction is begun before the end of 2019, is reduced to 26% in 2020, and 22% in 2021. After the year 2023, the residential credit will be eliminated and the commercial and utility credits lowered to 10%.

      Instructions for Form 5695 from the IRS:

  4. This does look intriguing. One of the options that we are considering is a bank of batteries to run our well pump during power outages. Although our location just wont work for solar, I believe we can still use a battery set-up with a trickle charger. This would appear to fill this niche. I will have to look into this a bit more.

  5. Dennis;
    I have recently moved to a better location and not ready for this yet, but;
    I have looked at this exact situation before. If the tax credits are still available, and if they only are applicable to grid-tied systems, I would think that you always have the option of “spec”ing a system as grid-tied with the option of adding a battery bank and a couple of battery chargers at a later date. It is still your property, you are paying for it but getting a tax credit for helping out the local power company so they don’t have to burn so much fossil fuels. Install the battery bank the day after the inspectors certify your system as grid-tied! Let it feed their system for a while to get whatever payback you can. In a grid tied system their system becomes your battery. So if at some time in the future you want to disconnect from being tied to their grid (or their grid stops supplying you with power) you will definitely need to have a charged battery bank online and ready to feed your lifestyle.

  6. To compare battery systems, I will use my system as an example. My system is a 48 volt system using Rolls Surrette S 605 batteries. I am not advertising their battery by the way. this is just my system. The total kilo watt hour capacity is 86.4. For max life ( 7 years at best @ $ 12,544 per system) I only use a 50% discharge, or 43.2 kilo watt hour. For 28 years the replacement cost ( at today’s battery cost) for my system would be $50,176.
    When I got a quote for the Edison battery system of equal kilo watt hour capacity the cost was $72,000.
    The maintenance of my battery system is a real pain in the a$$. The cost of refurbishing the Edison battery system was expensive. I purchased the lead acid batteries because after a SHTF event the replacement battery fluids for Edison batteries would not be available whereas I can and have rebuilt lead acid batteries. I hope this provides some insite into your purchase decisions.

    1. The S 605 is apparently rated for 468 AH (@ 20 Hr rate).

      8 in series gets you 48 volts @ 468 AH, which is 22,464 kwh capacity (100%)

      So it sounds like you might have 4 strings in parallel? 32 batteries?

      That would total 1,872 AH of which you are using 50% (the recommended max for lead acid), or about 900 Amp hours (43,200 kwh).

      Looking at Iron Edison, a 48V 1,000 AH battery bank retails for $37,000. This gives you 800 AH usable (80%). Although to be more comparable we might consider a 1,100 AH bank which will provide ~ 900 AH. This apparently lists for ~ 40K.

      Looks like you could replace your ‘S 605’ bank 3.2 times (7×3=21 years at best) for that. That’s if the lead acid batteries last for 7 years – which they reasonably should if they’re not regularly heavily discharged. 50% on a regular basis will definitely shorten the life span. Potentially by several years depending on the battery design itself.

      So it does look to me as though the Nickel Metal battery bank would last at least an additional 7, maybe 10 years than the 3x equivalent swap out of your lead acids. Potentially saving $12,000 or thereabouts after 28 – 30 years.

      Also saves the tremendous hassle (and back breaking work) of swapping out battery banks.

      I do realize though that there are other decision factors too!! Like the upfront costs…

      Thanks for sharing your system specs. The Rolls battery has a very good reputation.

      Also, you mentioned “The cost of refurbishing the Edison battery system was expensive.” I have not investigated this yet (the cost). Their site says “Electrolyte Refresh Rate: Suggested every 7-10 years to sustain maximum performance”.

      And yes, if I were planning for SHTF I would try to keep on hand enough for a refresh. Again, I have not investigated this cost. I suppose it’s quite fair to factor that in when comparing!

      1. Also as you replace those batteries over time, I believe the cost will be much higher every seven years actually making the Nickel Metal battery bank even cheaper. Say you buy your batteries today at $10,000, what will those same batteries cost in 7 years? Going by todays inflation, I would take a guess that in 7 years those batteries will now cost you between $11,000 – $13.000. Then go down the road another 7 years and what would the cost be at that point. In the long run I think the Nickel Metal batteries just might be the better deal.

    2. I read in another survival blog that some battery companies will sell you extra electrolyte for future use in case SHTF. Apparently if you store in the way you store dry food (in as air/water tight a container as possible, maybe vacuum sealed?) it will keep enough of its chemical properties to be used years down the road. Might be worth looking more into for those thinking of such a future catastrophe

  7. Thanks Ken,
    My wife had not seen this system before, she’s the one with the Masters degree and the brains in this outfit. We have a back up generator (LP) that kicks in if the power goes out. I have built a wood gas unit that will run a 10k Onan twin cylinder generator rescued from a burnt motor home. Have been building a HHO gas flash boiler to run a 8 hp steam engine the last few months also. But if I could just buy a full unit plug and play my life would be good. YOU THE MAN!

    1. Southernman,
      I can relate. Nothing quite like the smell of the woodgas gooo. I too, have experimented with woodgas. Filtering then filter some more, then one more filter. It is a doable thing. I’d love to learn about steam engines.

      Check out “ALL POWER LABS” for plug and play.

      I am afraid we will all have to learn about these things. There is supposedly a guy in SE Kansas who converts dodge pick-up trucks to run on wood gas. He gets 6 cylinder performance from a v-8. Pretty good, if ya ask me.

  8. I am friends with one of the owners of MidNite solar. He is a fellow Ham like me. He is a great guy and his company is top notch. Definitely do business with his company. I couldn’t recommend anyone else.


    1. I have purchased a number of items from them, including their popular charge controller. I’m currently running their ‘Classic 200’. Good company.

      Good to know you’re friends with the owner! ;)

      1. Yes, it is a great company. I have known Bob for probably 13 years or so. I met him through an Amateur Radio Club, The Snohomish County Hams Club, I was the President at one time.

        Take Care and stay warm Ken!!!

  9. I’m Impressed with Iron Edison, Very helpful staff, they gave me a free system design and I am happy with the Nickel iron batteries They put a 10 year warranty on the batteries which is much appreciated when making an investment. I will be a returning customer and would recommend Nickel Iron Batteries to anyone with batteries that need replacement.

    1. Thanks Aaron, the info is much appreciated! is 720-432-6433 still the right number for Edison Battery?

  10. Ken,
    I really like the hardware these folks sell, definitely some of the best, would be my first choice if i can ever get the cash together.
    The way electric prices are going and pretty much the prices of everything over here it will be well worth the investment, even with the cost of shipping.

    1. Yes, when it comes time to replace my existing battery bank, I will consider both of their types (Nickel Iron or Lithium Iron).

  11. I purchased a small set of Nife batteries, from this company. It’s a reasonably good battery. They will NOT provide the power as advertised. Significantly less. They even replaced the set, 10 cells, at no cost to me. Same issue. I would advise to buy way more battery than recommended.

    I still have the nife but have gone back to lead acid for my largest system. Both of my systems are small compared to some. My systems are totally off grid and diy.

    Would I buy them again? Probably not. Sorry Ken, just the facts. I can only go by my personal experience.

    1. Plainsmedic,
      I would be curious to know more of your specifics, if you care to share them.

      10 cells means you purchased a 12 volt system. Not knowing which capacity you purchased (100 AH, 200 AH, etc.,) I’m curious to discover your real world experience with capacity. In other words, if it was a 100 AH battery (1200 watt hour, or 1.2 kWh), how much capacity would you estimate it actually produced? Apparently 80% can be drawn off on a regular basis.

      My system presently utilizes lead acid AGM’s for storage. I’ve played with the system for a number of years and have come to recognize and isolate some of the inefficiencies of the various components… the solar panels themselves, the charge-controller/inverter (which has most of the inefficiencies).

      I chose a 48 volt system knowing that, apparently, overall it’s a more efficient system than 12 volts (factoring in all components).

      How have you ascertained that your own performance degradation is due to the batteries themselves (e.g. rather than or including the inverter, for example?).

      And how much less capacity would you estimate that your system had (percentage wise)?

  12. Yes, both of my small systems are 12 vdc. Kind of a cobbled up thing (not really that bad) as I bought additional panels and added (2) small 400w wind turbines. This was all done over a period of 3-4 years. My system(s) have remained the same for a while now. If I had it to do over again, I would definitely go with at least 24vdc or 48vdc would be even better. I just had to do it a little bit at a time.

    My nife are 300AH at 5hour rate, each cell is 1.2vdc. I worked with their folks for figuring how to power a refrigerator. This is the battery they suggested. On paper, it should work. In real life, it isn’t enough capacity to consistently make it through the night. I told their people exactly the controller and inverter I was using at the time.

    There are many variables involved; amount of sun, time of year, amount of wind, amount of usage, etc. I have upgraded the inverter(s) and one of the controllers. I’m sure my (3) 200watt solar panels are not as efficient as they once were. I came across a bargain for a few 100 watt panels and used them with my turbines on a different system. My systems have evolved over the years.

    I had an electrician friend of mine, look at my systems. He kinda chuckled and said “not exactly how I’d have done it, but it is safe.” My lead acid battery bank(s) have 0 and 00 stranded copper wire from one battery to the next. That is big wire and hard to work with. I have #4 solid copper wire running from each turbine, another bargain.

    I am not an electrician nor a solar/wind expert. Just a guy trying my best. I manage to use most all the power I can generate. That isn’t hard to do. I have a way to plug and unplug from each system to several outlets throughout the house. I can also plug and unplug from the two systems in the “battery house” which is just outside my home, less than four feet to my fridge. My two most consistent usage appliances are full size fridge and LARGE chest freezer.

    I’m hopeful I can provide some power in a shtf from the sun and wind. I have back-up controllers and inverters in faraday. With a little generator back-up, maybe we can get by. I’m not ragging on nife, it just isn’t quite what was promised. Was my equipment/appliances to blame? Possibly. They did replace the original 10 cells, with no improvement. I still have the nife batteries and have not contacted them since.

    1. Plainsmedic,
      I definitely found out how challenging it can be planning a system that consistently delivers the power you need. Winter – it can be tough! Not much sun (In fact, significantly less sun!). Also, clouds will greatly impact production. Sometimes where I live it can be cloudy for nearly weeks on end some times of the year! Anyway, thanks for sharing some of your details.

  13. Hey all – just found this article while on the site to read a different post. Anyhow, I thought I’d chip in with my experiences, having used a Nickel Iron battery bank of Edisons for 12 years now. I’ve been enjoying all the comments so far. Good reading!

    We run 37 batteries (only 100AH 1.2v each) for our system, 48 volt. Only one has ever given us problems, and we have a few spare. We got them in 2007, changed the electrolyte in 2014. About to mix up a new batch of electrolyte in the coming months, and this is the first time we’ve had to go out and buy the chemicals for it (had enough in stock from 2007 to make the second batch in 2014).
    At current prices, in Aussie dollars, it’s less than $250 to get the KOH flakes and lithium. We’ll get enough in reserve to mix up another batch in 2026.

    The electrolyte we currently have in the batteries is pretty cloudy and murky, but still works absolutely fine.

    Sure, it can be a pain to top them up with distilled water every couple of months, but at least it lets me check the condition of the batteries while it gets done. We recently got a home water distiller – which we run on solar power – to make our own at home, distilling rainwater from the tank.

    The batteries aren’t the good ol’ USA ones, our Nickel-Irons came from China (Changhong brand) and I can honestly say they’ve been rock-solid. Especially since I’m no solar expert and several times over the years got very slack and let the electrolyte run down, i.e. evaporate to only a third of their capacity). In short, I haven’t treated them well, but they’ve stayed the course.
    Really hardy units.

    Because I’m not really a number cruncher, and barely understand how it all works, I never bothered with return on investment figures. My only thought at the time was “how long will they last, and how reliable will they be?”, and so Nickel-Iron was the way to go.

    We have an Outback brand FlexMax 80 controller (from when they were made in the USA), and use a combination of several different brands (and wattages) of thin-film panels and CIGS panels. It’s a piecemeal setup, but has been very forgiving and reliable. The inverter is getting long in the tooth, so we’ve just ordered a new 3500W 48v unit.

    Solar enthusiasts – please forgive the ham-fisted post. As I said, I only know enough to keep it running, I didn’t install it, and so there’s probably a ton of criticisms or questions I won’t be able to address if any replies come along – although I could try. I’m one of those guys with “all the gear and no idea” :)

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