So I am chasing a battery drain somewhere and I am out of ideas. I replaced the battery with a new one, alternator charges at 14.7v. Once the battery is charged its good until it sits for 2-3 days , then is dead. One thing I noticed is the alternator housing gets to 160degrees (tested with my temperature gun). I think thats a little warm but no idea if it means anything. Could the alternator be draining the battery?

I have a few things wired to the battery through the fuse panel, heated/ powered seats (both turn off with the ignition key), HID headlights (off with key), subwoofer and amp (off with key). I verified they all turn off with no draw.

 

Disconnect positive cable, put an incandescent (NOT LED) test light between the battery and the cable. Pull fuses (pull, replace one at a time) until light goes out. Go for the headlights and AC first, it's not uncommon that the switches fail and pull current all the time.

 

Ive gone through same problem, ended up being the dimmer switch in the headlight switch drawing current...

 

K. Thanks for the tip. Wouldn't certain things cause a small draw even when off, like radio and ecu ? Or no?

Also, the alternator being hot?

 

If the alternator is overcharging and over heating the battery yes it could cause a loss of voltage on the battery, due to essentially frying the battery... Altermator could also get hot trying to compensate for a dying battery, very rare for an alternator to pull a draw when the key is off....have seen it but its rare

 

I did a test and found the radio circuit was drawing power when off. Amp meter read 2amps. I pulled the radio fuse and draw went down to 4 or 5 milliamps. So I pull the radio and unplugged it. Draw was still at 2amps. I checked my autometer gauges and unhooked them from the radio switched wire, draw went down to 4 or 5milliamps. I plug in the radio and draw was still low. I hook the gauges back up and draw went to 2amps. So looks like the gauges are the cause.

Would wiring in a relay fix the problem so the gauges won't drain the battery ? Wire it so the switched 12v powers the relay coil.

 

Guages should be on a switched feed anyway, they dont need constant power...