Battery Score 4

Well, so after crowing about how safe my charging regime is, I just had my first mishap.

When I went into the garage about 30 milutes ago to check the progress, I found that the Mil-Spac cell (this one is a Gulton brand) was disgorging small amounts of electrolyte out it's vent cap. I had been watching the liquid level in the cell with some concern, as it seemed like the cell was getting overly full, as if it had been manufacturing it's own electrolyte. Had I known this was going to happen, I wouldn't have added some distilled water before beginning the charging process.

Anyhow, I dumped the small amount of KoH off the top of the cell into the bottom of a cut-off water bottle, hosed the top of the cell off with the garden hose, then gave it a swabbing with a rag soaked in vinegar to neutrilise any remaing base. I then use an eye dropper to remove some of the excess electrolyte, and put the call back on charge.

This might be normal. I read a series of posts on the Electric Vehicle Discussion List a few weeks back about someone who had acquired some Nickel-Iron batteries that were completely dry. The were sealed batteries, and the user was wondering what to do about this before charging. He ended up just putting the dry batteries on the charger, and as if my magic, liquid appeared in the cell, eventually filling it to capacity!

The next one of these cells I charge, I'm going to leave it alone after cleaning it and let it make it's own electrolyte.

I do wonder about one thing, though. NiCd cells are supposed to have a layer of mineral oil floating on top of the electrolyte to prevent contact with the air. Seems that atmospheric carbon dioxide can contaminate the electrolyte, and carbonate it to the point were it no longer works properly in the cell. None of these batteries I'm fooling with seem to have any oil at the top? More mystery...