Hi
is it possible to overcharge a battery and damage it? I have about 5 Receiver NiCd Square 4.8V 600mAh batteries that I've had for a few months. I charged them yesterday for 24 hours because I forgot to disconnected them in the morning before I went to work. Well, last night I mixed them with 2 other batteries that were not charged so I didn't know what was or what wasn't charged. So I just put everything on the charger again. can they get damaged?

No I don't have a voltmeter, or a really good charger, just the standard plug on the wall type. Feel free to share links of good chargers