[dsraven]

while swapping a battery out it's a good time to check the configuration of your system. if you are using the battery and alternator set up from a donor vehicle it was likely matched to work with the system from that vehicle as far as loads and accy's go. your truck may have a different load set up than the donor vehicle had. start with the starter draw and work out from there. if you have a/c, a big stereo and a bunch of other power options then it requires more than a simple basic engine with no other power options that have a more continuous draw. the alternator and battery should match the vehicle otherwise they may be working overtime to keep up. also check the connection terminals at the battery because a terminal that looks clean, but has a black or dull finish on the contact surfaces, may cause a resistance which doesn't allow the alternator's voltage regulator to see the actual battery voltage. this can cause the alternator to overcharge the battery (usually noted by moisture around the battery cell vents) which will shorten the alternator and batteries life and also makes for electric options that seem a little dull.