Oh and I forgot to add.
It isn't the device over heating the battery usually but more like the materials in the battery being charged and used at the same time.
Most battery heating takes place when the device is in use and being charged.
The battery has to work twice as hard to push power and also pull power in.
I would not use the battery while being charged as that will most likely over time and probably a short time, cause the battery life to fail.
If you have to use it while charging, keep it to a minimum.
Talking on it and charging it will cause the most heating issues because talking pulls the most power from the battery and the battery is working super hard to keep it's charge.
Sorta like rubbing two surfaces together causes friction.
Power going in and power going out at high levels.
Also these are just my thoughts so take it how you wish.
I am not a doctor........ or an engineer.
