Can NiFe cells that have been dry for years be restored?

[audion_1908]

Hi, I have just got a set of 96 small glass nife cells from the 1930s, with open top but a dust cover! and some of the cells are dry and the others have the top of the plate showing above the electrolyte.

I also have some small steel cased nife cells probably from the 1960s, that are are completly dry!

If a NiFe cell has been left dry for years can it be restored?

What happens chemically if a NiFe cell is left dry?

I was planning to wash them in distilled water then mixing up some fresh potassium hydroxide and distilled water to a specific gravity of 1.150 to 1.200 and charge them up at 1.4 to 1.8v per cell (that what the steel cad nife datasheet wants) and the flatten them a few times to 0.9v and see if thay work?

I have to have the potassium hydroxide deliverd, its only 90% KOH but I could not find better

Is this a good way to do it?

[Mike90250]

If the cells have been dry, the iron/steel has likely rusted, and I don't think that is good. I don't know how to remove the rust.

I'd bought 2 spare cells for my bank, and decided to just place them into operation with the bank, giving me 2 cells, which really ups my charge voltage to the limit of my inverter. But the problems of having a couple idle cells, seemed worse.

[tandrews]

A dry cell simply lacks water, so unless it was emptied when wet, you will have crystal KOH left in the cell. Often appears as black tar (which will eat you given a chance).
The rust (FeO2) should be broken down in the first charge cycle. The crystallized iron may fall out of solution, but the plates are pretty thick on old cells and it may in fact increase surface area by the pitting it leaves behind. When you rinse, assume they have all the KOH they ever had and glove up. Dispose of rinsage properly or dilute to fertilizer level. This is stronger than drain cleaner and will mess up plumbing.
Glass cells are a bonus to see what you're doing.

The half-cell reaction at the cathode:

2 NiOOH + 2 H2O + 2 e− ↔ 2 Ni(OH)2 + 2 OH−

and at the anode:

Fe + 2 OH− ↔ Fe(OH)2 + 2 e−

They can be stored indefinitely topped up (to avoid the rusted plates) without ill affects other then self discharge (and/or carbonated electrolyte).
See thread: http://www.solarpaneltalk.com/showth...rge-efficiency
for some electrolyte info.

[audion_1908]

I have filled the steel cased nife cells and gave them a light charge last night, and thay dident hold much of it, I think the old electrolyte was tiped out not dryed up, no crystels, I will just have to wait 2 weeks for the 93% potassium hydroxide to make up the new electrolyte.

[tandrews]

Ever get a coffee that had a lump of unstirred sugar at the bottom?
You may be right about being drained wet, but you may also have sludge yet to dissolve into the new water.
Not saying this is what happened, just that it's a possibility.
Watching your glass cells may offer more insight than this.

Also, keep in mind that if the cell evaporated dry it is most likely the electrolyte absorbed C02 during that time, making the electrolyte (when it does dissolve) very inefficient at conveying any charge. Charging them until your new KOH arrives may be the best way to start fresh - they can take overcharges well and it will stir the electrolyte for you - beats tying a running reciprocating saw to your battery bank frame to shake things up...

[audion_1908]

tandrews how are you getting on with you old nife cells?

[audion_1908]

I put deionized water water into my nife battery but I will use distilled water next time, I want to work on the steel cased nife battery first as the glass ones are going to be a real pain as thay are in a real mess, and the steel cased nife battery is only shall 2 cells and probly 10AH, I have found a data sheel and it states the battery it to be chareged at 2.8v to 3.6v for 8 houre and its hard to read but maby 1.5 amps it even lists the specific gravity of 1.150 to 1.200 and nothing about adding oil so I won't?

I am planning on only using potassium hydroxide for the new electrolyte

[audion_1908]

data sheet

I have got a data sheet for my nife battery and its a nickel cadmium one not nife! and probly 8AH

[audion_1908]

I have a data sheet for NH10a nife NICAD battery

I got a data sheet from ALCAD and me nife battery is a nicad one! I also have 2 scanned lables from the lamp from http://www.mine-explorer.co.uk/bbs/f...ew.asp?tid=325
Nife-1.jpgNife-2.jpg
being a nicad battery raises some questions like old electrolyte disposal, because of the cadmium, I will have to neutralize it and take it to the dump.

how do I calcuate the amount of vinegar to put with the electrolyte to neutralize it?
my vinegar is 5% acetic acid?

and how will this affect the new new electrolyte? I know what the specific gravity of the new electrolyte fron the lables, but do I still need lithium hydroxide? and if so how much?

my new KOH arrived the other day

[Mike90250]

Well, you should not rely on a data sheet for NiFe bateries, to prepare mix for NiCad. I would hope the old electrolyte woudl not contain metals, so maybe you should research that a bit more. If no metal, no need to add acids to neutralize - just dilute and ferterlize with it.

Also look up the hazards involved in mixing acids with bases BEFORE you start.

[audion_1908]

Its only a small 8 to 10 ah battery so not much electrolyte neutralize, and because of the cadmium I dont want to risk the enviroment http://en.wikipedia.org/wiki/Cadmium_poisoning

(Well, you should not rely on a data sheet for NiFe bateries, to prepare mix for NiCad)
the 2 scanned lables are for my battery NH10A and give specific gravity or the new electrolyte and the charge rate, but not that the battery is nicad, or the makeup of the electrolyte.

(Also look up the hazards involved in mixing acids with bases BEFORE you start.) I have, thats why I have got some Disposable Nitrate Gloves and a face mask and 5 Litre of vinegar!

[Mike90250]

....
(Also look up the hazards involved in mixing acids with bases BEFORE you start.)

I have, thats why I have got some Disposable Nitrate Gloves and a face mask and 5 Litre of vinegar!

You are likely grossly underestimating the reaction of adding acid to base. Good luck, and have a helper with you , with a hose and hand on the valve.

[audion_1908]

http://www.youtube.com/watch?v=q8bA7CvR4zU

http://www.youtube.com/watch?v=-GEyQGKqd5k&feature=endscreen&NR=1

I will be careful, and use ice to slow and cool the exothermic reaction

[audion_1908]

I have also seen some pics of a large nife battery bank being setup, and the guy got chemical burns on his arms above the gloves by the potassium hydroxide and sweat!

[Mike90250]

I have also seen some pics of a large nife battery bank being setup, and the guy got chemical burns on his arms above the gloves by the potassium hydroxide and sweat!

Happened to me too, but just a bit different, the dust form the KoH settled on my arm, and it sucked the moisture out of the air, and started eating my skin. No sweat involved - it was actually a cool night.