tdereggi

When my car sits overnight 24-48 hours the battery is dead. I bought a brand new battery. I can disconnect battery, and have baterry sit for a week, then connect it back to car, and car starts right up, no battery voltage loss. I can drive through out the day, and alternator keeps battery charged. But if I leave the battery connected to the vette, key off and out of ignition, car sitting, it slowly drains battery, within a day or two. Im having hard time finding what is draining battery. Any ideas? First I thought it might have been my headlight, cause a screw kept keeping it from closing, but fixed that. Made sure it was not an interior or exterior light left on. I still have my internal door panels off. Note, this is not a starting problem. I replaced starter a month or two ago. And I confirm with volt meter that the battery has been drained to extremely low voltage.(near zero, even without load)

So what type things can draw battery current when car is off?

65Z01

What year Vette??

Disconnect the batt + lead and connect a DMM between batt & cable.
If drain is >30-40mA start uplling fuses one-by-one till drain drops.
Then analyze the problem circuit(s).

hooked073

one area that people miss is the lighted mirrors and the map light.

WVZR-1

You need to do a couple tutorials that discuss "parasitic draw". There are different procedures and I actually rather use the "negative terminal" rather than positive but find one that you're comfortable with and follow it to determine your issues.

This one was posted a few days ago and is well thought out. Take a look at it and do your self a "Google" search for others. Pick one that you understand and get started.

http://forums.corvetteforum.com/1587181735-post4.html

Do you have any after-market accessories in your car? What have you done recently in regards to service and maintenance? Start where you were working last! Do you have a FSM?

Post #2 mentions 30 - 40 mA and I'd think if you had a number close to that you would likely be good. Shoot for a number close to or less than the 30mA.

tdereggi

Thanks Guys,

I'll try those things, and report back. sounds like a good idea isolating it fuse by fuse.

ps. Its a 85 vette. I have a Chilton and Haynes manual, but not factory FSM. Last work done was replace AC compressor (the wiring to it melted but fixed it), replace headlamp motor, and remove doors panels to fix bad window motor and electric unlock. left panels off cause recarpeting. fixed those things, but did not fix the electric unlock yet.

65Z01

If you pull the sw from its socket you will find 5 brass pins ~1/2" long that are likely coroded and blackened.
Buff these pins with some emery cloth and TV tuner cleaner till shiny and your power locks likely will work again.

gerardvg

Check the antenna, it always has power supply. If the grease has dried out it will not go off via the limit switches, take the antenna apart and put some fresh grease on back and on the gears of the wheel assembly the antenna rolls into when going down.

The usual signs of the antenna motor not turning off via the limit switches is an intermittent "click" from the antenna overload switch.
That will flatten the battery in one to two days which i have found in my 85, the antenna motor could not retract enough to trip the limit switch.