More on Nickel Iron batteries….

24 07 2018

You read a lot of rubbish on the internet about batteries. It’s usually written by people who have very little experience with them too… for instance…:

The BIG reason to NOT buy NiFe batteries is they are incredibly expensive, they are charging you 9x the price of a lead acid and guarantying you only 5x the life. 

In reality, a Nickel Iron battery costs about double the price of a good Lead Acid battery. For example, a 12V, 300Ah Giant Power Sealed AGM Lead Acid Battery cost $669.00 online. This battery is rated at 1,850 cycles @ 30% DOD, which is 5 years. A comparable Nickel Iron Battery would be an Ironcore 12V, 200Ah battery rated at 7200+ cycles, which is 20+ years. This battery will cost you $1480.00……  and in reality give you more capacity than the above. It’s difficult to make a proper comparison, because in truth we’re comparing apples with oranges here….

So, if you are off grid and using your battery everyday, over a 20 years period you would have to replace that lead acid battery bank 4 times, and maybe 5 times….. With Nickel Iron you will never have to replace the battery, so over a 20 or more year period, you would have definitely saved money. More importantly, there will come a time it will be impossible to even replace the batteries!

NiFe batteries are VERY inefficient, which means a significant fraction of the energy you put in, does not get stored, something like around 25%. 

I am going to break this down into 2 parts. First, we are going to talk about Nickel Iron Battery efficiency, and then we will talk about Lead Acid Battery efficiency.

Nickel Iron Batteries are about 75% Efficient. The cells have been tested at the National Renewable Energy Laboratory, and below are the results. Overall at normal temps, they out performed their rated capacity between 75-80% efficiency.

Lead Acid Battery Efficiency – Below is a link to the Sandia National Laboratories results on Lead Acid Battery Efficiency. According to this document, they found out that when you are only using the top 20-30% of a battery, it really only has a charge efficiency of 55%.

So after looking at the actual data – the nickel iron battery is more efficient than a lead acid battery in daily off-grid charging, because you can discharge them as much as you like, and as often as you like without causing any damage whatever…. living with NiFe batteries is a completely different mindset that took me ages to get used to!

They are VERY VERY gassy, that is why there is such a huge head space on them to hold SO MUCH extra water, which MUST be distilled water ONLY. 

Nickel Iron Batteries do off-gas a little more than a lead acid battery, but this is because of the differences in the batteries’ chemistry. Both a wet lead acid and nickel iron battery require to be put in a battery box and I recommend using a vent fan or a whirly bird or two as I did in my container station.

The Nickel Iron Battery produces hydrogen when the battery pushes the oxygen from the water molecule to increase the oxygen concentration on the nickel plate. The head space is not huge on a nickel iron battery, but you do want an area for the electrolyte so you are not having to fill the battery with distilled water all the time. In my experience, I have to top my batteries up three times a year which takes about 20 minutes… 1 minute per cell.

A wet lead acid battery produces hydrogen through inefficient charging, when the electricity not used from charging is spent on splitting a water atom.

Both a wet Lead acid battery and Nickel Iron Battery use distilled water only. A sealed lead acid battery does not need water and does not off-gas, but has a much shorter shorter life if cycled everyday…..  or even if not cycled every day. I had sealed lead acid batteries in Cooran that were floated all day long that lasted just long enough to go out of warranty which was two years! A friend of mine in Queensland bought better quality ones that lasted six years….

They have a high rate of self discharge, so if you just leave them there, they can loose 10% or more of their charge PER DAY.

I reality, Nickel Iron Batteries have a 1% self discharge rate. If you are wanting a battery that will just sit there and not be used, then you might want a sealed lead acid battery. Sealed lead acid batteries are good for people that are not using their battery and want it to just sit there and hold its power in case the power goes out once a year or so…. personally, I think that’s a waste of time money and resources, last time I did this the batteries lasted just two years….

If you plan on using your battery every day, it really does not matter if it discharges 1%, because you are going to charge up the battery and use the batteries power next day. In my experience, that overnight loss is regained in the first twenty minutes after sunrise, so it’s a non argument……

edison EV

Thomas Edison with early EV

Of late, I have been thinking more and more about an eventual conversion of my trusty 4WD Bravo to electric drive. Never forget that NiFe batteries were originally invented for the very purpose of driving electric cars at the turn of the 20th Century……

Ironcore, from whom I bought the powerstation’s battery bank, sell 12V 10Ah batteries (actually 10 x 1.2V cells connected together) for $270. To achieve 120V por motor power, I’d need 10 of those giving me a capacity of 120V x 10 Ah = 1.2kWh or barely what’s in a litre of petrol! The old ute would go about 10km on that amount of fuel, but as electric motors are twice as efficient (or more) than ICE’s, it’s more likely it would go 20km. Furthermore, because NiFe batteries can be discharged far more than other types, it’s possible the ute would actually go farther, but of course that’s hard to predict…

Image result for 12V ironcore battery

10 of these connected together make a 12V battery

By having two such banks in parallel would double the range, which is probably about as far as I would need to go, especially after everything’s shut down from lack of fuel! Gathering firewood would almost certainly be its biggest task, and the forest is not very far away at all.

Out of the blue, an article about enthusiasts like me converting ICE cars to electric drives came up on out ABC internet website, which is what prompted me to write this while spending time in Queensland, supporting my better half looking after her 94 year old mother while the Tasmanian winter weather does its thing…. and the prime subject of these conversions is a ute, though unfortunately, while the batteries are mentioned, they are not shown, so I have no idea what this guy used… there’s a video at the link.



30 responses

24 07 2018
Bruce Teakle

Thanks for this post Mike – you should drop in while you’re in Qld!
On lead acid battery efficiency: I totally agree. Especially with flooded cells, efficiency isn’t such a big part of system design. You need to have enough PV capacity, it looks to me like at least about C/20, to equalise and gass your batteries well enough to avoid stratification, regardless of how much energy you need. Thus big batteries with small arrays die of stratification, even if there is enough PV input to cover daily loads.
Re electric cars: we do need transport for goods, but electric cars are a terribly expensive way to do this. My electric cargo bike uses between 5Wh and 20Wh per kilometre, depending on hill climbing and load. It’s so much cheaper in capital and running cost than a car, yet we see endless talk about how to maintain the driving culture in an energy constrained future. Most of the time, the personal electric car is the wrong answer to the wrong question. The community electric ute is more likely to be a goer.

24 07 2018

Like I said above, I need to be able to carry a tonne of firewood, at least until I have enough trees growing on our farm…. and I don’t think a cargo bike will cut it, especially at my age… 🙂

24 07 2018

Hi Mike, the batteries used by the guy in the linked article are Winston Lithiums, there is a full write up on a site called The Back Shed or TBS.
For some reason I cannot do a link.

Bruce, it depends on what you carry and how far for electric bikes, but for me a heavy duty electric trike is the answer, but one with a steering wheel as my shoulder will not work a set of handle bars.
With some panels over the cargo area it would be useable all day.

24 07 2018
25 07 2018

Capacitors realy need to be part of the storage mix. Capacitors can withstand many times the number of cycles, orders of magnitude more. Capacitors can provide massive rates of dischange and charge up so quickly. Capacitors store much more per unit size.

However capacitors are only short term storage, you will still need batteries. A super capacitor will discharge 50% to 100% in a month. Capacitor voltage drops as it discharges, much more than a battery does, so you need better regulators. You will need an output regulator.

Even with capacitors Tesla cars suffer from battery overheating with fast acceleration regeneration cycles, more capacitance would help. Stator overheating is still a problem that capacitors wont fix and which renders the Tesla useless in much of Australia (useless may be an overstatement but that huge performance will not be available)

25 07 2018

“Huge performance” is not something we should be chasing in a limits to growth scenario……

26 07 2018

My point wasn’t so much we need massive performance but major limiting factors of deep cycle batteries are their draw rate and limited cycles. Capacitors could extend the life of batteries and reduce how many batteries are needed. In some cases the size of the battery pack is determined more by the rate than the total storage.

Just as batteries have improved in performance and got cheaper, the same is happening with capacitors.

Downside is compexity. While the capacitor is simple the associated electronics are less so.

25 07 2018

Excellent Mike, thanks for this. Bookmarked for future reference.

26 07 2018

Hi Mike…are your batteries Ironcore….I seem to remember yours came from Russia. Are you still using rainwater. My rainwater is slightly acidic…apparently mild carbonic acid formed during rainfall by dissolving CO2…I have to neutralise it in my aqua ponics system. The electrolyte in the iron core batteries sounds a lot more complicated with Lye solution and lithium.

26 07 2018

Hi Sean, yes they are Ironcore, but they came from China, I mistakenly thought they’d be Russian….. David Bartlett from Ironcore recommended not putting the Lithium in the electrolyte, so I didn’t. The mixing of the electrolyte is not so much difficult as time consuming, because you have to do it slowly or kill yourself! Just joking….. but it took me 3 or 4 days from memory to fill my 40 cells….

I haven’t reached the water tank stage, and only recently discovered rainwater is slightly acidic…. a friend of mine who stores their rainwater in concrete tanks had problems with the acid attacking the joints in their Besser block tank causing leaks, but I’d never heard of this before.

4 08 2018

All my tanks have a noodle basket, filled with limestone chips, hung by wire (all 316 stainless) under the inlet strainer… alkalises the water nicely. I reckon it tastes better, and its healthier too! Something like this might help your friend with the besser block tank?

I think distilled water is supposed to be neutral, but as Sean noted, once it touches air, dissolved CO2 will drop the pH. Do NiFe’s have a preferred water pH?

And how much water do you use each top up Mike? And are you just buying it, or distilling it yourself? I recall an old forum thread where some guy called himself the “Water Boy” he was doing it that often!

Also, my understanding is with the Lithium, you should get about 10% more out of the battery… why wouldn’t you put it in?

My cheap GEL batteries are still holding up (surprisingly) well, but I expect to be getting my NiFe’s in the next few years, so I appreciate your insights into living with ’em Mike!

26 07 2018

Thanks for reply….a battery bank is next on my list and few people have heard of NiFe. Lye could me made from wood ash at a stretch but I don’t think lithium will be easy to come by.

26 07 2018

I can’t remember why David said to not add it, but he is VERY knowledgeable and will talk you ears off if you let him. It’s actually great to get good support and advice for a change…

4 08 2018

Tom Murphy of “Do the Math” fame has recently posted this…:

In other news, my Nickel-Iron batteries seem to be holding up well (I owe a post on some real analysis of these). I am “living the dream” in my daily commute. After 12 years off a bike (obvious routes are dangerous; hilly profile would require time-inefficient shower), I finally solved the problems: (longer) trail route and an e-bike (off-grid-solar-charged). Purists would say I’m cheating, but I say I’m back on a bike and working plenty hard. The rough-hewn route exposes me to wildlife (the occasional coyote or bobcat, even), has a few stream crossings, and enriches my life by offering a daily connection to the natural world. My propulsion energy is now free of direct contributions from fossil fuels, which I find to be rewarding—even if the materials/manufacture are still utterly dependent.

I keep ckecking his website for an update, and wait with bated breath….

19 09 2018

I heard a comment there was a company in Australia manufacturing Nickel Iron Batteries . Is that true ? If so is there anyone to contact that could revive production of the anode and cathode plates ?

20 09 2018

It’s news to me…….

18 12 2018

Its expensive but longest lasting battery.

19 09 2019

Myself I have a bank of Iron Nickel batteries(20 x 200ah), they are 6 months old. I followed all the instructions, always kept them topped up with distilled water. However my problem is that they only hold 2.5kw/hr of charge which is well below what I was told they would hold ( 4kw/hr). Also they guzzle water, 30 litres in 6 months. Is this “normal”?

20 09 2019

When new, they need to be cycled hard, charged discharged a lot, and draw big currents out of them often. This builds up capacity, to such an extent it’s possible to actually get more capacity than they are rated at….. the fact that you’re going through so much water – they are thirsty batteries – tens to tell me you are floating them too much….. without knowing what voltage range you are using or what gear you are charge controlling with, I can’t be more helpful, sorry……..

20 09 2019

and thats exactly what I did……… per Iron core’s instructions. 33V, no float, full discharge every day for at least a month. My solar charge controller was putting in 70amps…… no problems there. When I first got them, they were delivering the full 4+ kw/hr of charge and then they started dropping off to the point after 5 months I just could not keep water up to them even at 32V and the output had dropped to 2.5kw/hr. I was really disappointed because of all the good things I had heard and the cost of them………so what went wrong?

20 09 2019

I never used float………..when I contacted the guy, there was no help. He was defensive,hostile and wasnt interested in any trouble shooting, technical help or having one of the units sent in for analysis. I was at all times polite and calm, but customer bashing seems to be there idea of “customer service”. I strongly got the feeling I wasnt the only customer with problems.

6 10 2019

Problem solved…………..after doing a lot of reading and research. Turns out that Potassium Hydroxide is best suited to cold climates and Sodium Hydroxide is best suited to hotter climates ( like mainland Australia). So I tipped out all the ( 6 month) old KOH electrolyte and replaced it with 24% Sodium Hydroxide, I was lucky to find a local supplier who had 99% pure 25kg bags for $45! When removing and rinsing out the old KOH it was for the most part very black in color and sludgy in the bottom of the cells. So I dont know why that is? Was the electrolyte contaminated from the beginning? With the new NaOH and distilled water solution the 20 x 200ah batteries are now putting out a whopping 5.3kw/hr at C/10 discharge rate which is amazing!! Turns out Iron Core are useless idiots who know very little about their products.

30 10 2019

Hi Wazza. am having some issues with an ironcore battery install myself.
where did you find the info that NaOH is for warmer climates and KOH for cold? i also have black coloured electrolyte and sludge at bottom of cells to the point one cell short circuited. cheers

11 11 2019
warwick robertson

I read every research paper I could find using google. The situations is that Koh has a lower freezing point than Naoh. However Naoh has some better qualities such as charge retention. So if you dont have low temperature issues, then Naoh has some advantages. It is easier to get, and cheaper for starters. Thats important, because it seems to me, that if you dont have a massively over sized bank in amp/hours then the electrolyte itself works a lot harder doing full charge/discharge every day. Essentially it doesnt last as long. So the fix is to replace the electrolyte when performance drops off. All the manufacturers say that along with the original Edison manual. You will need to tip the old electrolyte out, half fill with clean water, shake strongly and then rinse out all the black crud from inside the battery. Then immediately refill. DO NOT let the battery stand empty for any length of time. Make sure it is refilled as soon as practical.

8 12 2019
David Bartlett

Dear Warwick, its interesting that over the 13+ years we have been selling NiFe Batteries and the thousands of sets of batteries we have sold, we are now according to you “idiots who know very little about their products”. You say we were defensive and hostile. I am happy to provide all the emails received from you to show otherwise to anyone who is interested. We offered 6 times to assist you. We have always gone out of our way to assist every customer who has a problem including “Marty” where we identified the problem and as far as I am aware they are now working properly.
I will remind you that you had done your research before you purchased your 200ah x 24volt (4.8kWhs) of batteries from us. We had no input into your usage requirements. You did tell us in an email after you had purchased the battery, the battery bank only needed to provide power for you but now there is now a second person and you also run a air-conditioner.
In emails to us, you stated that a 24v x 200ah (4.8kWh) battery bank from Iron Edison was able to provide over 5 kw / per hr of power. I am happy for you tell people you are able to discharge 5.3 kw / hr out of your battery bank that is missing one cell due to you not maintaining it properly. I am impressed you now are able to discharge 5.3kw / hr out of our 4.56kWh battery. We do not advertise or tell people our batteries can provide more power than their rated capacity.
We do not sell our batteries with Sodium Hydroxide because our manufacturer does not provide warranty with this electrolyte, nor do we. Potassium Hydroxide works with all the ranges of temperature of the Australian climate. It has been used for over 100years in NiFe batteries including in Australia for over 30 years when the Australia Government used to use them until they could no longer purchase them. We have customers in the Northern Territory, North Western Australia and Far North QLD using potassium hydroxide and they are not having any issues.
We cannot be held responsible for how you use, program, how you maintain our batteries or the purity of the water you use however we have never turned any customer away from any help we can offer if they have a problem, as we did with you. In every case the issue was not with the battery.


10 12 2019

I have to say, I could not be more pleased with our batteries. They are actually performing well above my expectations. Now that we have moved into the house, with no running water yet, hot or cold, and no AGA to cook on or heat water with, we’ve been using the solar power system to meet our needs, without the batteries ever flinching even….

I wouldn’t be wanting to do this in winter obviously, but it wouldn’t be because of a lack of battery storage, it would be because of lack of sun! By next winter, the AGA will be operative, and we should be just fine running the rest of our loads off the batteries n matter what the weather throws at us.

10 12 2019

As David says above, it really pays for your system to be installed properly. A friend of mine in Tasmania recently had an Ironcore battery bank installed by a fellow named George who as far as I am concerned, has no idea what he’s doing and should stay away from solar altogether. I actually wish David would stop recommending him, he’s not doing himself any favours.

Brigitta’s system is 2 1/2 times as big as ours and her battery bank about 2/3 the size. Her system shuts down nearly every night, and it’s all down to poor design and installation…..

17 01 2020

UPDATE: Brigitta’s MPPT, which is built into her Victron inverter, had died, and it appears, from info gleaned from installers in the know, that too many panels were hooked up to the device, and it’s cooked. George should definitely stay away from this stuff, he obviously has no clue…

17 01 2020
Dr Michael Chudacek

Well all the comments are very interesting. I am Chemical Engineer and NiFe cells are my pet project. With respect of electrolyte there is no chemical reason why NaOH cannot substitute KOH in a warmer climate. Addition of small amount of LiOH would improve charging ability of the cell as the smaller Lithium+ ions move much faster through the electrolyte than much larger Sodium+ ions or even larger Potassium+ ions. From the above NaOH filled cells should also theoretically charge faster than KOH filled cells. I have no experimental data available to prove the above hypothesis. If you have a lot of time at your disposal, you can give it a crack.

I believe the Russian NiFe cells are of higher quality than some Chinese brands I do not dare to mention for an obvious reason. Does anybody know if there is a Russian NiFe cells supplier in Australia?

31 01 2020

I didn’t add the lithium supplied, lithium is toxic and I intend to use the depleted electrolyte at end of life to either make soap or as a spol additive for potassium and acidity regulation……

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