When I first started using LiPo batteries some years ago I was very careful when charging, always outside on a slab of concrete and monitoring constantly. Over the years I have become somewhat complacent, my current method being charging in the loft where I am usually working (my model workshop) so I am there pretty much all the time they are charging with perhaps the only exception being to pop downstairs to make a cup of tea.
On this particular occasion I was charging a 5cell battery which was getting on a bit and a bit puffy, after a while as I was working I kept hearing a faint clicking sound, eventually I realised it was the battery which was now swelling alarmingly, the clicking was one of the cells splitting. I immediately disconnected the battery, picked it up by the leads using a pair of Molegrips and took it downstairs and outside. I first put the battery in a plastic bucket intending to pour water on it, I then thought if it bursts into flame it would melt the bucket and cause a right mess, also, I am not sure if water would have helped. I then put the battery in a plant pot, as I did so it started to emit smoke, at this point I decided I had done as much as I could and left it to settle down. I returned to the loft to disconnect the charger from the power source, as I did so my wife shouted me to tell me the battery was on fire, when I got down stairs again there was a sheet of flame about 5ft high burning furiously, the fire burned for a minute or two before burning out. From hearing the clicking to the battery bursting into flame took no more than two minutes, I used to leave them for perhaps five minutes when making a cup of tea, even longer some times. The consequences don’t bear thinking about, I have no doubt with the intensity of the flame up in the loft there would have been little I could do and the whole house could have gone up in flames.
We hear about these things happening and tend to think “I would never do that”. The message is clear, please review how you handle your batteries particularly when charging, make sure you charge in a safe place, preferably outside and on a suitable surface, remember two minutes left alone is too long.
John Wright.
LEMAC Chairman.
