Nickel-Iron woes.

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:



This the worst of the cells.




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:



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.

Photowhit

Silly question, but you have been  using distilled water in them? (ya' never know...)

dRdoS7

Hi,

Photowhit said:

Silly question, but you have been  using distilled water in them? (ya' never know...)

Never a silly question.

Yes, only use distilled water. I started distilling a month so after I installed them: could see how much they used, and how much it would cost if kept buying it.

Good thing you spell it Photo, not Foto. Had a guy at work his initials were FW. Lived up to it, often.

Thanks,

dRdoS7

Aguarancher

You might consider sending in both a sample of the battery sludge and your home distilled water to a lab for analysis. Between those two you should be able to tell if the problem is on yours or the battery mfg side of things.

Dave Angelini

None of the links work in my chrome browser.
What make are the batteries?
There is a member here Mike who can give you his opinion as a user.

Photowhit

Photos,  from site hosting  if  you aren't signed in member they won't show, I was kicked of at least 2x correcting sun'god' but keep getting reinstated...

dRdoS7 said:

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:

This the worst of the cells.

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:


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.

mike95490

What you have is not normal:

Initial install pics (Oct 2011)
https://www.facebook.com/pg/Lucky-Monkeys-Ranch-120212794718849/photos/?tab=album&album_id=209715335768594

Refresh pics: (Aug 2018)
https://www.facebook.com/pg/Lucky-Monkeys-Ranch-120212794718849/photos/?tab=album&album_id=2113125788760863

Still going strong.

 I question if you have enough solar, if it took you 3 months to get the batteries running properly.  It takes me 2 summer days, or 3 winter days of full sun and normal loads to recharge.

softdown

Looks like nobody has been able to open the photos. I get "invalid file" when trying. 

Photowhit

softdown said:

Looks like nobody has been able to open the photos. I get "invalid file" when trying. 

You can see them in my post? 'right click copy' and 'right click pasted' into the post.

dRdoS7

Hi,

mike95490 said:

I question if you have enough solar, if it took you 3 months to get the batteries running properly.  It takes me 2 summer days, or 3 winter days of full sun and normal loads to recharge.

I started with 3KW, then after 2 years I installed another 4.3KW. I have plans of putting in another ~3KW soon. I find in winter, sometimes what I have isn't enough. But then what is? I could say the same about battery capacity too.

The system was installed so I could maximise my solar exports, have enough to run through the night, and the occasional blackout. By 2024 it will have paid for itself. We have had no power bills since 2013, and receive a good credit each year. The system was doing what I wanted until late last year.

softdown said:

Looks like nobody has been able to open the photos. I get "invalid file" when trying. 

Tell me if you can see this one:

Thanks,

dRdoS7.

dRdoS7

HI,

Photowhit said:

softdown said:

Looks like nobody has been able to open the photos. I get "invalid file" when trying. 

You can see them in my post? 'right click copy' and 'right click pasted' into the post.

I just signed out, then had a look, and I can see all the photos, maybe it's a browser problem?

dRdoS7

softdown

I can see the last image.  Your first effort still shows "O views" for all three image links.

I can't recall an active poster with NiFe cells. Transparent housing is interesting. You are on the grid maximizing "solar exports" yet use batteries for energy storage. Mark K might have a chance at diagnosing these NiFe woes. 

dRdoS7

Hi,

softdown said:

I can see the last image.  Your first effort still shows "O views" for all three image links.

I can't recall an active poster with NiFe cells. Transparent housing is interesting. You are on the grid maximizing "solar exports" yet use batteries for energy storage. Mark K might have a chance at diagnosing these NiFe woes. 

Strange. Whether I'm logged in or not, I can only see photos, no links.

See through cases make it easy to see the electrolyte.

I can see what you mean when you mention my exports & batteries. I have 2 separate solar systems. One system is connected to the grid, for export and home usage, the other is not connected to the grid, which has batteries, and is for home usage. Actually it is plugged in, for backup when batteries are low, but can't export. They each have their own AC circuits. Most house appliances run from the 2nd system. Some large usage items like the oven & Air cons don't. Also house lights don't. I'm working that now, and am having a c/o switch installed. ATM, the more I run from the 2nd system, the more I don't use from the 1st, which means more is exported. Once the switch is installed, I'll be able to run everything (within inverter limits) off solar/battery storage, with grid as a backup. Also be able to connect a genny, just in case.

dRdoS7.

Here's the other 2 photos:

This is from testing of 7 faulty cells. I ran a distiller early morning, turned off solar, and measured each cell as the volts dropped. LHS column are cells numbers and the colour of each line is which group they are in the battery bank. Pink & Red are highlights so the seller could easily see the drop points.

Photowhit

dRdoS7 said:

Strange. Whether I'm logged in or not, I can only see photos, no links.

Logged in here or at 'solarpaneltalk.com' where the photos are hosted,  the  reason  I 'copied  and pasted' them here in my reply,  so everyone could see them  without being logged into solar panel talk.

dRdoS7

Hi,

Photowhit said:

dRdoS7 said:

Strange. Whether I'm logged in or not, I can only see photos, no links.

Logged in here or at 'solarpaneltalk.com' where the photos are hosted,  the  reason  I 'copied  and pasted' them here in my reply,  so everyone could see them  without being logged into solar panel talk.

That's even stranger. I can see the photos here, logged in or not, but not the ones on SPT unless I log in there.

To save time, I copied the text from SPT, so that must have copied the photo's links too. When I pasted here, the photos were pasted, but I didn't know it was the links.

dRdoS7

dRdoS7

Hi,

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.

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

According to the specs., a 200Ah cell should weigh 14kg.

I'm wondering if anybody who bought new cells has weighed them. If so, were they up to spec?

I contacted the seller a "few" weeks ago, and the cells he ordered have arrived in port. Said it would probably take another week (or two) before he has them. Then another week before he has charged/discharged a few times, and will send them to me.

Of the 6 cells I flushed, and renewed, only 2 are working. The other 4 still acting the same as before, and I've removed them from the bank.

Currently running 35 cells.

Thanks,

dRdoS7

BB.

I thought (no battery expert me), that NiFe batteries did not have any "consumables" in the plates. It was just the electrolyte that needed changing (basically because CO2 was absorbed into the electrolyte (some solids formed)?

I would be  (a little) surprised that the cells would lose weight over time...

-Bill

dRdoS7

Hi,

BB. said:

I thought (no battery expert me),

Me neither!

that NiFe batteries did not have any "consumables" in the plates. It was just the electrolyte that needed changing (basically because CO2 was absorbed into the electrolyte (some solids formed)?

The CO2 forms carbonate (maybe I have learned something!), but stays in suspension, no solids should precipitate out.

I would be  (a little) surprised that the cells would lose weight over time...

I'm not that surprised that they were low. Probably lost weight sometime after the specs were issued, and samples tested.

I do not think any cells have lost any weight, except the ones I flushed. It's more likely they were underweight when I received them. 1kg less of Nickel+Iron, per 200Ah cell, would save the manufacturer a bit over the years. When I'm finally sent some replacements, I'll weigh them, and see if they are a "bit" light on too.

Here in Australia, we had a recall, in 2015, of Infinity electricity cable (made in the good old PRC) due to the breakdown of the plastic insulation coating.

Remember the melamine in milk not so long ago?

Thanks,

dRdoS7