The bad news: As with most "low-battery" has also this battery no thermal fuse!
Using a simple ohm meter and a desk lamp can be easily verified that: If you measure the original battery at room temperature the electrical resistance between the contacts "-" and "T", the meter displays a value of about 10k to. If you heat the battery now, where you hold it for 30 seconds, for example, directly under a desk lamp, and then measures the resistance once again, it's only about 5kOhm. (The value will then slowly rise again while the battery cools down.) - About this resistance change recognizes the charger if the maximum permissible temperature is exceeded and stops in case of failure the charging process off.
Carrying out the same experiment with the replica by, to measure at room temperature while also 10k, however, this value does not change if one heats the battery. - Here obviously a cheaper fixed resistor has been installed instead of an expensive thermistor which deceives the charger always a same temperature. The charger has therefore no chance to detect overheating the battery and stop charging. - I therefore recommend strongly that you charge the battery only under supervision, so that you "just in case" can quickly pull the plug!
