Li-Po Battery Charging

LiPo batteries can be very dangerous - read on...

With the current popularity of electric micro-helicopters, I thought the following should be brought to everyone's attention:

Reproduced from ELECTRIC LITE HELICOPTERS LITHIUM BATTERY ADVICE (Steve Dorling)

Lithium Polymer Batteries have transformed the capabilities of electric powered models and they represent a truly startling increase in duration over Nickel Cadmium and Nickel Metal Hydride cells but the dangers of the latest Lithium technology cannot be over emphasised!

Handled with care and consideration and a strict adherence to charging and discharging instructions, your Lipo cells will behave like any other battery. On the flip side, using the wrong charger or overcharging the cells will see them replicate a small bomb and this is no exaggeration!

An overcharged Lipo cell will indicate its discomfort, firstly by swelling up and ballooning before eventually bursting into flames with a powerful explosive detonation. The heat from the resultant fire, combined with the explosive discharge will cause major injury or worse to any unfortunate victim nearby and if cells are maltreated indoors there is a real possibility of a major conflagration leading to loss of property or life.

The following guidelines are strongly advocated if accidents are to be avoided:

Charge cells ONLY using a dedicated LIPO charger whilst strictly following the instructions for the device
Ensure that the correct NUMBER of cells are being charged before hooking up your cells
NEVER exceed the 1C charge rate (ie for 1000mA charge at 1 amp max 2.5 amps for a 2500 pack etc etc)
NEVER rely on "Automatic" settings on charging equipment - carefully select the parameters you require
NEVER leave cells charging indoors at any time even (especially) when you are in the room/house!
Do NOT approach a discarded "blown" cell until at least half an hour after removing it from charging equipment and placing it safely away - this is the most lethal time - in your hands you have a time bomb so get rid of it and fast!

The last point is a very salient one, given that one of our close friends overcharged a cell (wrong charging parameters) to destruction recently. Only by chance was he alerted to the charger alarming as it finished the cycle. Approaching the battery he realised by its distended appearance that all was not well and having the presence of mind to immediately place it outdoors he retired to the house whereupon an explosion a few minutes later and one that would have done credit to a small stick of Semtex shook the windows of the house. Outdoors where the battery had been a huge two metre jet of viciously hot flame continued to burn for a full ten minutes. It could have all been so much worse and had the battery detonated in his hands he may well have not survived the moment. Had he not immediately removed the battery, a major house fire would have resulted.

YOU HAVE BEEN WARNED - this is not a scare story passed on down the line, but rather a first hand account of the dangers - TAKE HEED!