NiCd batteries

[amiklic1]

I got two 240 Ah NiCd batteries. They are in some kind of wooden frame. One battery contains seven cells. They're haevy as h.ll! I am just beginning to charge them. They come from a train company, and have some voltage ( about 9V).

There is a labal on them says that I must fill them only with distilled water.

I hope I could use them for my PV and wind power battery bank.

Anyone knows something more? At least charging current, or so. I got 10 A battery charger, and it seems that they need to be charged 24 hours to be full.

[Ampman354]

I didnt think that NiCd batteries had water in them.  Could be wrong and im sure this is stupid to ask but are you sure that they are NiCd and not flooded lead acid?

[amiklic1]

I was confused too, but manufacturer's original metal emblem on them says:

NiCD battery

240 Ah

Charging: 48 Amps / 7 hours

Warning: do not use sulphuric acid.

I'll try to contact the manufacturer, maybe they know something more.

[DanG]

The electrolyte is probably aqueous potassium hydroxide (KOH) solution in concentration of about twenty percent... excess electrolyte is available for cells above the plates, often 2+ inches. These type usually have light-mineral oil floated on top of electrolyte to extend maintanace intervals.

Charging rates should be gentle - battery never designed for fast recharge.  If it gets more then warm to the touch back off charge rate. Use distilled water to bring up levels but never top off flat batteries, likely easy to loose electrolyte from boil over.

Your find is an excellent stand-by battery for short interval high current systems that use continuous duty generator power - battery power used to ensure safe unattended generator shutdown-startup from power interuptions.

[Nando]

Short response.

The electrolyte is KOH at about 30 % concentration, the water evaporates and the KOH stays, so get Distilled WATER ONLY.

The battery cell voltage when charged is 1.37 per cell and during charge it may go as high as 1.47 to 1.57 depending on the type you have.

Good luck with them you may have many years of productive life if you take care of them well.

Regards

Nando