Dead (New) Battery....Cause?
 

I last drove my 90 Corvette, Saturday aft. a week ago. Put it in garage as usual and left it along until
yesterday. When I got in it I heard a sort of clicking sound sounding like it was coming from the
glove compartment. Didn't figure I was important enough for someone to bomb me so I turned ignition and tried to start it. Dead as a doornail. (And battery only 9 months old.) I put one of those portable
jumper chargers on it and tried again but again nothing started (jumper down on juice). There was enough juice to barely light the under hood lights and cause a fan to start blowing. ???? After recharging the portable jumper and trying again, the engine fired up and no fans on and no clicking sound. ???
Drove it a few miles to charge up battery and no problems. Question......what could have caused this?
A switch or relay sticking when bringing it home hot after last weeks run? (I didn't notice any fans on
when putting it up last week. ???? Any ideas? Thanx

RE: Dead (New) Battery....Cause?
 

It's possible that you have a weak cell in the battery, andmaking the alternator run the car, and charge a battery wth a weak cell, the other 5 cells in the battery were overcharged, and cause them to go bad. The alternator may have a bad diode internally, causing it to discharge the already weak battery. The alternator installed on your car will "pop" if you try to make it run double duty, (charge a dead battery, and run lights, A/C, sound system, ignition, fuel pump, brake lights, etc. for very long (week, two weeks)
I recently had a battery go bad after installing it 5 weeks ago.
There could also be ahigh resistance to ground in anything that has a wire on it. you will have to get an ammeter, and disconnect various fuses, and accessories, etc. and hook up the hand held ammeter to see if there's a battery drain. when there seems to be no movement in the needle, move on to the next item, and see if there's a drain there.

RE: Dead (New) Battery....Cause?
 

Ditto. Im going with the bad cell in the battery.

RE: Dead (New) Battery....Cause?
 

It's easy enough to load test a battery. Even the crappy, low priced parts stores will do it for you for free if you don't have a load tester. If that's eliminated as the problem, then you need to check for current draw. If you find it, take out one fuse at a time until you pin down the circuit in which it's occurring. From there, it's simply a process of elimination in finding the cause. A factory service manual is invaluable when doing such troubleshooting. It will provide circuit diagrams, component locations and other info that you're unlikely to find elsewhere. We are assuming here that your charging system is up to snuff, right?

RE: Dead (New) Battery....Cause?
 

Come work on my car for free.:)