Nickel-Iron woes

**dRdoS7** · 02-07-2020, 03:15 PM

Hi,

Originally posted by Iansworkshop

I found some references to gunk in NiFe in another forum but 'I may be being stupid' but can not find a way to PM u with links.

Just post them as a reply here, that way others can use them too.

Thanks,

dRdoS7

**Mike90250** · 02-07-2020, 05:08 PM

When rigging up a scheme to add and remove batteries from a bank for charging and discharging (to keep from over voltaging an inverter) you end up overcharging some, and undercharging others.
What else can I say.

overcharging cells should have only consumed more water, but if they started getting hot, that's never good.

Why did you feel it was ok to over-voltage the cells while charging (1.7v vs 1.65) ?? Did the battery vendor instruct you to do that ? Was the vendor aware you were switching cells in and out? These are all RED FLAGS that you contributed to the demise of you cells.
Here's a trophy

**Iansworkshop** · 02-08-2020, 08:42 AM

Originally posted by dRdoS7

Hi,

Just post them as a reply here, that way others can use them too.

Thanks,

dRdoS7

I've applied to join the forum at navitron.co.uk but have yet heard back yet I think because they ask for a real email address i.e not hotmail gmail etc it appears that some members on this forum get a bit 'hot under the collar' but however try this link https://www.navitron.org.uk/forum/in...html#msg187870

**dRdoS7** · 02-09-2020, 05:33 PM

Hi,

Originally posted by Iansworkshop

Found this on another forum I'm not making any claim that its right or in any way useful, but may give a few leads for further investigation

1. Take a few ml of electrolyte out of one of the cells
2. Add water to electrolyte to form gunge
3. Take some more electrolyte from the cell and add to gunge until it starts to dissolve
4. Leave in air and see if it goes orange around the edges

This isn't an exact procedure and you may need to fiddle about a bit

Explanation

Earlier in the thread I seem to recall that you washed out one of the cells with water and ended up with loads of grey gunge? When a NiCd or NiFe battery discharges Hydroxides of whichever metals are present are formed. These are soluble in the Potassium Hydroxide solution but not in water.

I was thinking that if you take a small amount of battery electrolye it will contain the Hydroxides of Nickel and Cadmium or Iron depending on the type of battery. If you take a few ml of this and add water you should get the gunge forming. If it is a NiFe battery there should be Iron II Hydroxide in the gunge which you can test for Iron content.

I don't know what the gunge looks like - if it's lumpy you could catch a lump and put it into a small container and add a little more electrolyte (which you haven't added water to) from the battery to make it just begin to dissolve again. If it isn't lumpy just add a bit of electrolyte anyway.

In an alkaline solution (which you have created by adding the KOH in the electrolyte) any Iron II Hydroxide in the gunge will be oxidised to Iron III Hydroxide which is orange. If there's iron present it should start to happen around the edges where the gunge is in contact with the air

I missed this earlier.

The gunk in my cells is already visible in the bottom of the cells. That's how I knew there was some, even before change the electrolyte.

Thanks,

dRdoS7

**dRdoS7** · 02-09-2020, 06:04 PM

Hi,

Originally posted by Mike90250

When rigging up a scheme to add and remove batteries from a bank for charging and discharging (to keep from over voltaging an inverter) you end up overcharging some, and undercharging others.
What else can I say.

The failed cells are from various parts of battery bank, so I don't see it has any bearing. The crud is also in 37 of 40 cells. The ones without are also spread around.

overcharging cells should have only consumed more water, but if they started getting hot, that's never good.

Why did you feel it was ok to over-voltage the cells while charging (1.7v vs 1.65) ?? Did the battery vendor instruct you to do that ? Was the vendor aware you were switching cells in and out? These are all RED FLAGS that you contributed to the demise of you cells.
Here's a trophy

The cells were already failing, and had crud in the bottom, before changing from normal charging settings.

None of the cells ever got hot. I had a temp sensor on one, and that got to 31C. A couple of cables did get very warm though, could still hold them.

The seller told me to charge them at a high voltage to see if it fixed the faulty ones. It does actually appear to have fixed one that didn't have a flush and electrolyte replacement, and 2 that did (probably only temporary). I'll see when the 4 really bad ones are replaced.

But anyway, thanks for the award, which I really do not deserve. I'm sure there are some worthy candidates.

I do believe I should get a Darwin Award, or at the very least an Honorary Mention, for the one I 'sploded.

Thanks,

dRdoS7.

**dRdoS7** · 02-23-2020, 03:28 PM

Hi,

Just a quick update:

I've weighed a few of the cells to see what the difference is between those with no debris, those with debris, and those that have been flushed and renewed.

Condition	#	Weight (g)
Has Debris	7	12894
No Debris	6	12973
Cleaned & Renewed	8	12420
Cleaned & Renewed	18	12447

The cells that have been cleaned lost about 450g. That tallies with the amount I recovered.

According to the seller, the cells he ordered have arrived in port. Said it would probably take another week before he has them.

Thanks,

dRdoS7

EDIT: Tables not working to well here. I've as well.

cell weights.jpg

**Iansworkshop** · 02-24-2020, 10:23 AM

Hi

Do you know what the correct weight for the cells should be, is it 12900 or 12400 , If its the lower weight that might suggest impurities had got in and maybe cell 6 with no debris has already been compromised but not yet developed the debris, maybe its been over filled. Long shot I know but just throwing a few thoughts into the mix, as usual with anything that goes wrong it may be a combination of things. Given new cells are arriving soon which will get u back up and running an explanation may never be found. Let us know how u get on with the new cells

**dRdoS7** · 02-28-2020, 01:15 AM

Hi,

Originally posted by Iansworkshop

Hi

Do you know what the correct weight for the cells should be, is it 12900 or 12400 , If its the lower weight that might suggest impurities had got in and maybe cell 6 with no debris has already been compromised but not yet developed the debris, maybe its been over filled. Long shot I know but just throwing a few thoughts into the mix, as usual with anything that goes wrong it may be a combination of things. Given new cells are arriving soon which will get u back up and running an explanation may never be found. Let us know how u get on with the new cells

According specs, each cell should weigh 14Kg filled. Possibly they've been on a diet! Possibly the manufacturer has overstated that, or it was for the first few production runs, but has been reduced to save them money. Cell size is the same as in the specs.

One good cell weighed 12973g, and one that hasn't been cleaned is 12894g. The two low weight cells (previous post) have been cleaned. That is some slimming program.

I spoke to the seller, and he has new cells in stock. He's going to charge them, and send me 6 new ones next week. It will be interesting to weigh the new ones, and compare them to the originals.

None have ever been overfilled. Nor have they been allowed to drop below the minimum line. I want to protect my $8000 investment. Though some got very close. I check them a couple of times a week, so I have an idea of when they'll need more water. If we're going away, top them up a day or two before leaving. That doesn't happen much as I usually turn everything off. I'd spend the time away worrying about them running dry for some reason. It's OK for a couple of weeks though, I drop the charge settings a bit. Not much is running if we're not home.

I was reading through the emails I sent the seller, and saw this:

When I had the faulty cells on the floor, I noticed some grey matter in the bottom of both cells. I've attached a photo of each one. I one it is up to the separators, the other double that height. None of the other cells that I can see, are like that. 19 are on 2nd. row of shelving, and behind the first 19, so I can't see the bottom of those.

That was almost 2 months after the first email about low cell voltages. So the rest of the cells have been deteriorating since that date (early June 2019).

Thanks,

dRdoS7

**dRdoS7** · 09-02-2020, 02:23 AM

Hi,

Been a while. The 6 cells I was expecting didn't arrive. I contacted the seller in June. He told me they weren't holding a charge, and didn't want send them. He said he had more coming, and would send 10. No contact for a few months. Called him last week and told him I wanted to return the cells, and get a full refund. Left it at that, called again Monday, and he agreed. He is going to refund 50% this week, and the other 50% when I return the cells, at his expense. So my NiFe adventure is over (hopefully). Sadly, it didn't work out as planned. They worked wonderfully for about 2 years.

I've ordered 18 x 280Ah LFP. What could possibly go wrong?

Thanks,

dRdoS7

**Mike90250** · 09-02-2020, 10:19 AM

Originally posted by dRdoS7

Hi,

.......................

I've ordered 18 x 280Ah LFP. What could possibly go wrong?

Thanks,

dRdoS7

Does it come with a BMS (a complete BMS, over, under, full, cold, hot) and a way to integrate it with your charging source ? If the BMS cannot control your charger, it's the wrong one.

**dRdoS7** · 09-14-2020, 09:23 PM

Hi,

Originally posted by Mike90250

Does it come with a BMS (a complete BMS, over, under, full, cold, hot) and a way to integrate it with your charging source ? If the BMS cannot control your charger, it's the wrong one.

I've bought a BMS, it does what a BMS does.

The BMS has an RS485 connector, but neither of my devices, SCC nor Inverter, have any method to allow them to be controlled. Any out-of-spec values will cause it to shut off the bank to them both.

Thanks for your input.

NiFes go back next week.

dRdoS7

Nickel-Iron woes

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