Apogee Magnum Battery Fire
Ok this time it was not a user error, but probably a procedure that should be avoided. I bought this Apogee Magnum Battery because it was advertized by the seller to be a safer chemistry. Here is a detailed description of the incident. I charged the pack up on a FMA direct charger until it finished its fast charge and started a slow charge (which is followed by a slower charge). I removed the battery installed it in the Pantoura and was waiting for a sparring partner so I topped it off with the Astroflight charger at the rate recommended by the seller (2 C). The charger should have gone immediately to top off mode. In less than a minute the battery had ballooned to twice its original size. It had flexed the graphite top strap up about 1/2 to 3/4 inch. I unplugged it tossed the whole car to the end of the table away from the racers for further work. I decided to save the car. I put a small vent in the outershrink with the X-acto to prevent explosion. We put a towel over it. I put on glasses. I unscrewed the top strap and popped the battery out onto the concrete slab. I left it there for a few minutes, but it was not in a safe condition. I put the towel back over it and sent the X-acto deep into the guts. In about 10-15 seconds there was a loud pop (heard 150 yards away) followed by a little mushroom cloud of white smoke and the towel was on fire. Yes Red Flames. The towel was a self extinguishing material so it was not consumed. Here is a pic. This is the approximate postion of the parts when I opened the towel later. Don't change chargers. Who would have thunk it.
I have had two of these packs for 30 cycles and recently bought the new one which had 6 or 7 cycles on it when it caught fire. The two original batteries tested well when new and dropped a full .25 Volts and lost 500 mA-h in 30 cycles. The new pack was probably from the same batch as it tested indentically poor to the used packs. Probably deteriorates more from age than use. Anyway another overblown product performs miserably. I just hate that.
A Scorpion Pack which was a Lithium Cobalt Dioxide pack kept its specs much better over 30 cycles. It too ended in a fire.
I have ordered one of the Orion Avionics Packs as they are now available. They were not when I bought these.
Track report in my next post.
Last edited by John Stranahan; 10-12-2006 at 07:38 PM.