Hi,
I have a FIO r2 I think (blue one recently purchased from SF).
The charging IC gets very hot (to the touch) when I am charging it via either 5v 1A wall wart (also from SF) or USB.
It seems to get hotter with a fully drained battery than one that is half charged.
Is this normal?
If you can touch the IC without burning your finger then this sounds normal.
When the battery is drain its voltage is lower and the IC must dissipate power as heat. The IC must supply more current to over come the voltage difference. This power is the voltage drop across the IC times the current through the IC.
Thank you.