Battery replacement problem checking voltage

I bought a replacement battery from Ebay. It reads 3.8 volts across the 2 outer terminals on the ribbon cable that connects to the main board. I installed the battery and noticed the board was getting warm. I immedieily desoldered the battery from the board. I don't think it should be getting hot. I installed correctly but why is this happening? The ipod shows no water exposure. I also have some other broken 2g touchs they read 0 volts where it connects to the board. Does this mean the battery is bad? Or do I need to measure the voltage on the board on the battery? I am an electronics tech so I have a good knowledge of repairng stuff.

Thanks

Thanks