But a proper charger will not do that.
Recently I bought a SONY DCR-HC40 camcorder, the SONY BC-TRP charger and an extra SONY NP-FP70 lithium ion battery pack (quick charge battery). I charged the battery that came with the camcorder (NP-FP50) in the SONY BC-TRP charger and, by mistake left the battery in the plugged in charger overnight.
1) Is it possible to overcharge a lithium ion battery by leaving it in the plugged in charger overnight, as I did?
2) According to the instructions for the charger, I can leave the battery in the charger for an hour after the charge light goes out (indicating a full charge) and the battery will charge even more. Are there any disadvantages in doing that?