Guess where I spent the afternoon? In the emergency room due to a lipo blowout.
I use a Thunder Power 610C charger which has served me well for a year. I was charging a Tenergy 3.7V 500mAh 15C battery with a Tarantula Eight-in-One RC Charging Cable. I had noticed that this battery had quit early on me on a flight yesterday and, in testing with a volt meter, I saw that it was not fully charged. I thought that maybe I had accidentally missed charging it with my other 6 batteries, so I put it back on to be charged. I knew there was something strange about how it was acting. It was charging too long and the the charger was not shutting off, so I shut it down before it finished.
Not thinking about it again, I prepared to charge another battery, but got up to open the window. While I was up, I heard a "whoosssssh," turned around to see the battery blowing smoke like an Estes rocket engine on take off. I immediately knew that I had to get it outside the house before it burnt the place down. I always charge batteries in a safe place, but I feared this thing could shoot around or explode or something. Well, I picked up charger in all to quickly take it outside, but in the process, I flipped the burning battery on the wires onto my hand.
You can see in the photo that I have 2nd degree burns on my right hand. Not too bad, really, but I now have a burned hand and a burnt floor where the battery broke off the charger.
Here's the analysis:
o I knew that this battery was acting strange and I should have marked it and gave it special consideration when I charged it.
o I did everything right for most part--I did not leave the charger while charging, I monitored its charging and stopped it when I saw that it was over charging.
o The charging wires were burnt up all the way back on the 8-in-1. That indicates that there was a short circuit either in the battery or in the wire harness. I actually am suspecting that it could have been the wire shorting out first just because it looks very melted. I think it contributed to the charger not sensing the correct level of charge as it should have, and over-charged the battery.
o I immediately pulled the plug on the charger which may have saved a larger problem with the suspect wiring.
o I should not have picked up the battery, but let it finish burning--since it was on a safe surface.
Thanks to my wife
who happens to know where the emergency room is from another mishap earlier this week (not me!) and calmly drove me there.