Batteries dying overnight

One little trick I learned with my tahoe, I would pull the covering off the fuse area and stick a meter into each pulled fuse to see if there is any current still flowing. There are like three rows of 12 or so fuses each in most of the slots. And you wont believe what still continues to draw power when the truck is supposed to be OFF.

After weeks of investigating with that stupid meter drumroll please... hood light. Yes the stupid little bitty hood light bulb when the hood is shut. It never turns off. Leave it long enough boom dead battery.

I had a monster spiral gel deep cycle 1200 amp battery on that engine for a couple of years that constantly exhibited being sick. Until I pulled that light off tossing I was beginning to think I was either a mental defective with a complex or the battery itself is a POS fancy. Unfortunatley the situation went on long enough to kill it. Once you kill it and jump, it's probably the first or second to last jump you will be able to do before it dies completely.

 

Yay! I get to replace 4 batteries tomorrow! Got one (or more) cooking. Gotta love waking up to that sulphur smell!

 

Keep eye on your operating voltage. A bad alternator can fry the next four as well.

 

Remember that the sulphur smell is sulphur gas and is highly explosive one spark when unhooking the battery cables can cause a large explosion sending shrapnel and battery acid every where.
Definitely a job that calls for gloves and safety glasses.

 

Common problem I have with this is the battery connection loosen up. So much as a quarter of a turn on any connection will kill it. I got rid of the stupid nuts that screw down battery post and replace it with car batterys with top post connection

 

And just the opposite can happen as well. Bad batteries can cause overcharging. Had a KW just the other day came in with the volt light coming on and showing 15.5 while running down the road. Customer had replaced the alternator twice to no avail. 3 of the 4 batteries were bad.

To add to the op... ... if you do find a drain on the system. The first place to go is the alternator. Disconnect the charge wire to see if it is the source of the drain. I have seen internally shorted alternators drain batteries in a hurry. Often people jump to something left on and easily overlook a the component when hunting for a draw.

 

Thanks I never saw that one! The worst I ran across had a fried battery. Thrifty company X ( very local ) had one battery put in. I do not recall all details as it took several months. They called me to come and look at it as it has a problem, I thank this was a few batteries later. The battery box looked like a steam locomotive. It was really almost unbelievable. Ended up the alternator would stick full tilt around 17 volts and 130 amps. Shut it off and it would work normally later.
If the alt is warm 4 hours after you park it is bad.