battery problems

[twistyplain]

I have used the Chinese charger with a adapter to fit New Zealand power sockets since I bought it except on a couple of occasions at work when I had to borrow a charger from a Samsung Galaxy phone, would have thought using that would have been safe? Am I wrong about that?

The output power of the Galaxy charger might be way higher than what your battery was made for. It would be safe if you charged it to about 90-95% but once you fully charge the battery and leave it connected, it's like you are forcefully feeding the battery and it's already full. Without an overcharge protection circuit, the poor THL battery will have to take the extra charge and that will definitely damage it.

Overcharging causes oxygen gas to be produced in the battery - that's what causes the battery to swell. At this point the battery is also highly explosive because the electrolyte in li-ion batteries is quite flammable. Needless to say, the capacity of the battery is severely compromised when you overcharge it until it swells. This is why you see li-ion batteries charged to 100% full dropping almost all their charge within a mater of minutes (or seconds).

If a phone's battery is not completely destroyed, you can get 1-2 hours of usage and then the phone goes off without warning. Such a battery also charges from 0-100% suspiciously quickly.