here's the problem, if I leave my carpc on without music playing/not using the pc battery lasts to about an hour and half, but if i have music on (not blasting) or playing with the pc battery lasts for about 15 mins.. is this normal? the battery is brand new just got it from autozone (Duralast Gold battery) and if it matters I have 2 amps and 2 12" subs installed