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

[audion_1908]

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

[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]

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]

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.

[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.

[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?