Hi All

                            PERHAPS A TIMELY WARNING

This is the time of year most of us put our boats away for a few weeks and enjoy the festive season. Some of us do maintenance, repairs and upgrades in preparation for the coming sailing year.

Batteries are a key ingredient of radio sailing and I'm sure everybody would be aware of the do's and don'ts regarding the care of batteries. From a safety point of view, don't expose them to excessive heat, put in a fire, overcharge or short-circuit and use correct sized conductors when making connections. I would therefore like to share a very recent personal experience with you which could have resulted in a disaster.

Some of the battery packs for my IOM are becoming a bit aged and are losing performance. When I go to a two day event I find it difficult to maintain adequate charged batteries, so I decided to try my hand at making a battery pack. Not difficult and I won't describe it in detail. I couldn't source shrink wrap and used cling wrap instead which works perfectly well, saving 2 gms in weight! I needed a female Deans plug for the leads and only had a male plug, so I burgled a plug from one of the 'aged' packs. After desoldering it from the existing pack I put this pack aside and completed my new one, which appears to work well. Later I moved the discarded battery pack to a bedroom and put it on top of one of my model making tool boxes. A day later I had cause to move this and noticed the battery pack looked strange. When I picked it up the shrink wrap had burst open and the plastic outer casing to the batteries themselves had split off. Everything was sticky. The lid of the tool box was melted where the battery pack had been sitting. What had happened was the bare ends of the power leads had accidentally come together, shorting out the five AAA batteries and generating what appeared to be very substantial heat, cooking the batteries and causing the damage described. I haven't pulled the thing apart yet but it appears the bottoms of 2 of the batteries have melted or split, allowing black material to leak out.

Conclusions:  This could have started a fire when we were away from the house. Perhaps it could have exploded when we were in bed. I have to admit it did not even occur to me that a) the discarded battery pack was still charged (maybe fully) and b) I should have protected the bare ends of the power leads. It is too easy to be casual about tiny little batteries which power our pencil light torches or portable clocks. I have walked around at interclub events with perhaps 30 volts worth of AA & AAA batteries in my pockets.

Batteries probably should always be removed from boat & radios when finished sailing.

I intended to put this in the Newsletter, but Jim beat me to the punch and I thought it worth sharing sooner than later.