Nickel-Iron woes

[dRdoS7]

Hi,

If there was a way of getting a sample of the sludge it wouldnt be that hard to get it analyzed.

I'll let the seller do that. He's going to replace some cells, then I'll send some back. I'm sure his supplier will be keen to know what it is as well! Or not.

If I ever find out, I'll post here.

I have almost a full 2 litre container of it, so yeah, not difficult. I've weighed it, and have about 2.5Kg. That's about 400g/cell (plus what's been flushed out and discarded). I suppose it's probably less actual crud, because it still has some moisture in it. Maybe I should spread it out to dry.

Thanks,

dRdoS7

[peakbagger]

If there was a way of getting a sample of the sludge it wouldnt be that hard to get it analyzed.

[dRdoS7]

Hi All,

I've installed my 42, 800ah cells back in 2010 or 2011. In 2018, I did an electrolyte refresh (took a solid week of hard work), and they are still going strong.
I am very scrupulous about keeping cells sealed to prevent CO2 poisoning and only use tested De-ionized water for refilling. I've some terminal penetrations that developed some cracks, and those have been superglued closed. I closely monitor and log pack voltage daily Seller may have has a batch of bad cells, but it's not a NiFe normal situation.

I saw & read you posts on here a while ago, glad mine are 200Ah.

Mine came filled, so all I had to do was connect them, and cycle them for 3 months. Took that long before they were working to full capacity. By mid May 2018 I had 80% efficiency. Currently it's around 60%.

I like the emptying rig. When it's time to renew the electrolyte, I'll make something similar, but with the axle between two cells so it's balanced. Also probably have a hose & valve in each so when upended it can be controlled. From what I've read: Empty 50%, shake a bit (cells that is), empty the remaining. No flushing, except with used, filtered old electrolyte.

I'd also do them in small batches (of 4) so I can keep using the inverter. That way I can take time, mix up small lots of electrolyte, etc.

Did you get anything (gunky) out of your cells?

What does the battery vendor suspect causes the gunk buildup ? The Ni Fe plates do not exchange material like lead acid batteries do, so there is no plate shedding, Have you ALWAYS used pure water for refilling ? Did plates EVER get exposed to air ?

He was supposed to contact his supplier (China), but hasn't said anything about it to me. He has said he will replace the 4 really bad ones. Don't know about future cells. We haven't got to that yet.

I bought some distilled water (20litres) from an auto spares shop after I installed the cells. Than I bought a distiller. I refill the containers that the DW came in, and also a few drinking water containers (10l & 15l) that I bought. I have about 130l all up Keep them tightly sealed. At worst they could absorb some CO2 while filling, or not completely full, but I don't think that would cause my problem, just create the carbonate which would be in solution in the electrolyte, not precipitate as black gunk.

Always reseal cells after filling. Never used anything other than my DW.

If this is the only example of a black gunk problem u can find from other NiFe battery users and I have asked two off gridders in the UK who use NIFE sorry they had not experienced the issue. But one said something about "the powder held in pockets on the plates had maybe come out, but thinks this only applies to one particular type of cell". I would think your next step should be to get a sample of the gunk to a lab and find out what it is. However I've emailed a couple of contacts I have (from when I explored using NiFe) to see if they have any idea whats going on, but both are Chinese manufacturers so given the currant situation in China I've no idea if I'm even going to get a reply. They are bound to ask who manufactured the cells.

Yeah, I thought disintegration too. I'll let the seller worry about lab tests. He obviously thinks it's the cells, not anything I've caused. I know they come from China, that's all. When I've received the new cells, I'll send back the faulty ones. The seller can work it out with his supplier.

More than likely there was impurities in the water which cause a reaction and the creation of sludge.

Not sure about "more likely", "possibly", maybe. I use a distiller, so I hope there's only DW going in to the cells. Any ideas as to what impurities it would need to be?

Thanks,

dRdoS7

[SunEagle]

What does the battery vendor suspect causes the gunk buildup ? The Ni Fe plates do not exchange material like lead acid batteries do, so there is no plate shedding, Have you ALWAYS used pure water for refilling ? Did plates EVER get exposed to air ?

More than likely there was impurities in the water which cause a reaction and the creation of sludge.

[Iansworkshop]

Hi,



I do not think that a balancer will help at all in my case. The problem is the gunk build up. I cannot see imbalance being the cause of that.

If this is the only example of a black gunk problem u can find from other NiFe battery users and I have asked two off gridders in the UK who use NIFE sorry they had not experienced the issue. But one said something about "the powder held in pockets on the plates had maybe come out, but thinks this only applies to one particular type of cell". I would think your next step should be to get a sample of the gunk to a lab and find out what it is. However I've emailed a couple of contacts I have (from when I explored using NiFe) to see if they have any idea whats going on, but both are Chinese manufacturers so given the currant situation in China I've no idea if I'm even going to get a reply. They are bound to ask who manufactured the cells.

[Mike90250]

What does the battery vendor suspect causes the gunk buildup ? The Ni Fe plates do not exchange material like lead acid batteries do, so there is no plate shedding, Have you ALWAYS used pure water for refilling ? Did plates EVER get exposed to air ?

[Mike90250]

I've installed my 42, 800ah cells back in 2010 or 2011. In 2018, I did an electrolyte refresh (took a solid week of hard work), and they are still going strong.
I am very scrupulous about keeping cells sealed to prevent CO2 poisoning and only use tested De-ionized water for refilling. I've some terminal penetrations that developed some cracks, and those have been superglued closed. I closely monitor and log pack voltage daily Seller may have has a batch of bad cells, but it's not a NiFe normal situation.

Refresh pics: (Aug 2018)
https://www.facebook.com/pg/Lucky-Mo...13125788760863

Initial install pics (Oct 2011)
https://www.facebook.com/pg/Lucky-Mo...09715335768594

[dRdoS7]

Hi,

Can not help you with recovering the cells as I use lead acid, however I have 12 budget 12v leisure batteries in a 24v series-parallel bank. Over time some pairs drifted apart in voltage. I added HA01 equilizers/balancers and over the following few recharge discharge cycles recovered useful capacity. My understanding is that in your situation you would have to use the HA02 version of the balancer, again my understanding is that its unlikely to recover your dead batteries but once you have fixed/replaced your dead cells it might reduce or stop similar problems in the future

I do not think that a balancer will help at all in my case. The problem is the gunk build up. I cannot see imbalance being the cause of that.

There is a method of regeneration that will create a build up:

Take out the battery, and whilst the electrolyte is still in, wire the positive and negative terminal together, then apply a 12 volt circuit using the case as a the negative and connect the positive to the joined positive and negative terminals. He then says "leave this on for a cycle" whatever that may mean. I left mine on for 12 hours. Its supposed to drive the build up off the plates and it settles in the bottom

After the end of the cycle disconnect the 12 volt circuit tip out the electrolyte - it should be dark grey or black and on one occasion it was very reddish. After tipping it all out then wash the battery several times to get the gunk out. Once the rinse water is clear, its ready for new electrolyte.

Can't do that with mine, as this applies to original Edison cells, which have a metal case. Besides I have gunk, I don't need some more.

Possibly the electrolyte is at fault. This is what I am trying to find out. Maybe I'll never know, and end up with 40 new cells.

Sorry for you battery issues. But I thank you for showing that most battery systems may only last about 3 years and still need to be monitored a lot to keep them "happy" and productive.

I don't think think this experience implies there is a problem with NiFes, or that they'll only last 3 years, just this batch. You only need to look at some of the other posts about them to see they can last a very long time, don't need to be thrown out out after 10 years, but can be regenerated. They do require a bit more work. I have usually only needed to top up the electrolyte over the past 3 years. It may be that the newer version of these cells isn't as good as the originals. But I haven't read of anybody else having any trouble. One user here has renewed his electrolyte after 7 years, but that was doesn't appear to be due to any failure, just did it sooner, rather than later.

Thanks,

dRdoS7

[SunEagle]

Sorry for you battery issues. But I thank you for showing that most battery systems may only last about 3 years and still need to be monitored a lot to keep them "happy" and productive.

[Iansworkshop]

Can not help you with recovering the cells as I use lead acid, however I have 12 budget 12v leisure batteries in a 24v series-parallel bank. Over time some pairs drifted apart in voltage. I added HA01 equilizers/balancers and over the following few recharge discharge cycles recovered useful capacity. My understanding is that in your situation you would have to use the HA02 version of the balancer, again my understanding is that its unlikely to recover your dead batteries but once you have fixed/replaced your dead cells it might reduce or stop similar problems in the future. My understanding is that the balancer effectively diverts currant to the cell/battery that is under charging it also works in reverse when discharging. NB to get the resolution on the added voltmeters I used a 10v zenor and resistor add 10v to the voltage displayed to get actual battery voltages.

HA01 balancer.jpg

[dRdoS7]

Hi,

I have 40 x 200Ah NiFe cells, which I bought & installed in 2016.

Early last year I started having cells fail to hold charge. I happened to be up early, and saw the voltmeter on one group of 10 cells was lower than the other 3.

I tested each cell's voltage, also noticed that some had a layer of black debris in the bottom, in one it was up to the plates.

The voltages in them would drop to 0.6V, then -0.2V as the bank was discharging.

Also they were really bubbling, even though no charging was occurring. Charge going from the good cells into the bad?

Actually, checking back through my log of daily charge/discharge Ah readings, I found mention of a few that had problems, but that was short term, and they were OK once I'd had them for a while. They've been really good since mid 2017, and even better after I upgraded the inverter, and added 4KW of solar to the existing 3KW in 2018.

The seller sent me a bag of KOH, which I used to replace the electrolyte. I gave 6 of the cells a good flush, and got them totally clean before replacement.

After putting them back, and several charge/discharge cycles, I started testing. Then another went -0.2.

So now I've had 7 now go "bad".

I then really overcharged the 7 of them (1.9V / cell). More testing , 4 didn't recover, 3 possibly did. The last bad one I didn't clean out or renew.


Here's some pics:


IMG_20190503_122448-smaller.jpg
This the worst of the cells.



IMG_20200115_075528_3-smaller.jpg
This the crud in the bottom. Don't ask why there's no plates!
I will add that I have only 39 now.


These are the last lot of readings:
7 39 cells test.jpg


Anyway, the reason for the post is to ask if any other NiFe owners have seen this.

Be interested to know, there seem to be a few owners here, and some have had experience with them for a long time.

The seller is going to replace 4 cells, as soon as he has some.

My concern is what will happen in the future. Of the 40, only 3 have no crud in them.

I am assuming the crud is from the anodes and/or cathodes disintegrating.

I've been Googling, but found no mention of my experience.

Many thanks,

dRdoS7

PS. I have posted this in a few other forums, trying to get as much info from others as possible.