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Old 6th Jun 2016, 2:39 am   #27
Techman
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Join Date: Nov 2009
Location: Lincolnshire, UK.
Posts: 4,985
Default Re: Amazing D cell discovery!

I agree that these Procells are dreadful and leak at the drop of a hat. The thing is that they didn't used to a few years ago. I used to buy the 'AA' type by the box of ten for £2 a box when I was at work. I also used to buy the Procell PP3 alkaline for £8 for a box of ten. These used to be good, but the last batches I bought I found that they were either down to 7 volts or had started to push the ends out while still well within date and still in the box. It seemed like three or four out of a box of ten would be dud when needed for equipment.

The Procell 'D' cells sometimes need some care. A piece of kit was reported as getting warm and fizzing. The 'D' cell was running red hot. It was quickly removed and put in a bucket of water and left outside for a while to get over itself! When inspected after warming up the water and flattening itself, I found that it had been 'scratched' at the negative end by a rather sharp edge on a battery holder when it had been inserted therein. The positive connection runs down the outside of the case below the outer label and is crimped round the negative end with just a VERY thin insulator between the two. This crimped edge of the negative end had been 'scratched' by the rough battery holder which had damaged this insulation causing the cell to develop a dead short - a terrible design!

As for the swelled top PP3 batteries - WARNING - I needed some PP3 connectors for something I was 'bodging', so I decided to salvage the top connectors from some of these dud batteries I had put to one side. As soon as I released the top connector plate the cells inside began to explode. I left one on the bench and stood back as the inside cells went off like a shot gun. My work room had one of those tiled suspended ceilings and the inner electrodes of the cells shot up and embedded themselves in the ceiling tile above. I left them there and pointed them out to others as a warning - I've got a photo of it somewhere, if I can find it I'll post it up.
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