txnese

Not sure if I'm hitting or pushing a button or switch unknowingly, but I recently decided to leave convertible top down, and my battery is dead by the morning. The days I don't leave it down, no problems. The battery is about 6 months old. It's a manual top, so not sure what I'm missing. Any ideas? Thanks in advance.

charliet615

I have a 93 vert and seldom put the top up.(Garage Kept) Never had a problem with the battery being low or parasitic draw. I start it up/drive every two weeks. Sorry I don't have a solution. I'm sure the top being up or down has nothing to do with it. I would make sure that the interior lights go off.

JimLentz

Try this,
1. Open top
2. Shut off everything
3. Open hood
4. Disconnect battery and put ammeter in series with battery to measure load

The load should be less than an amp, if not you then have to figure out what is causing the current draw.

Klondike

This is a good start. THEN, I'd start pulling fuses one at a time and check the meter current draw after each one. If no change, reinsert it and go on to the next. When you get to the problem circuit you will see a drop in your meter current. Then you'll know your problem (or left on switch) is on that fuse ckt's line.
OR, You can also just measure voltage or current across each empty fuse hole as you pull them. One at a time so you don't get them mixed up. When you get to one with a load on it your meter will jump as you will be completing the circuit with the meter. If everything is off, there shouldn't be any voltage/current load to read across any of those pulled fuses. When you find your loaded circuit, see if there is a stuck or turned ON switch in that line.

Purple92

You might want to do a search on parasitic draw. Lots of people run into dead battery problems with this.

Fundamentally - when the cars computers fully "go to sleep" the current draw is on the order of 15 - 30 milliamps. However this is not as simple to measure as you might think....

If leaving the top up solves the problem with battery draw - your troubleshooting should be somewhat easier....

WVZR-1

Top is manual but the cover is power actuated.

If you're quite sure that it's a "TOP DOWN ONLY" situation I'd pull the 25AMP "HATCH FUSE" #45 and continue maybe to leave the top down a few nights and see if the battery lives. If the battery lives then you only need to check that circuit.

Do you use the PKE function? I'm not hinting it's involved but the car has the capability so it might be interesting to know.

Do you have the FSM?

Dead in an "overnight" situation certainly seems odd.

hcbph

Here's a little something that might help. You pull a fuse and plug it into the unit and plug the pigtail in where the fuse was. It will show how many amps are being pulled on that circuit. I had a problem with mine I was trying to track down and it worked like a charm.

JimLentz

Great idea!

hcbph

I picked that up at HF though I've seen it on EBay and a couple of other sites.

Hot Rod Roy

I tried to review the specs of this HF Circuit Tester, but couldn't find anything about the lower limit of its readout. Can it read less than 0.05 A (50 mA)? That's what you want for total battery drain, after the computer "goes to sleep" and the interior lights turn off. If it can't do that, you're better off making an adapter by soldering two wires to an old burned out fuse, to connect to your own DVM. (Save your $15)

JimLentz

It says .1 amp accuracy, but I am sure they mean resolution, so a minimum of 100 mA.

Hot Rod Roy

Does that mean 100 mA, +/- 100 mA? 'bout right for HF!

The total parasitic drain on the battery of my '84 is 13 mA (0.013 A).

hcbph

Check things like the well in the console. I had issues and found I'd put a wrench over it and the wife had put a lipstick tube in there and it was pressing down on the seat adjustment. It was causing a continuous battery drain in my car till I noticed it. That little tool helped track down the circuit that was causing it.

kg4fku

There shouldn't be anything drawing power based solely on the top being up or down. Nothing is turned on or off based on the position of the top.

There may be something coincidental to the position of the top but nothing directly related.

Is there anything not factory installed in the cabin of the car? Something like a stereo or an alarm or perhaps extra lights?

WVZR-1

The OP hasn't posted back for nearly a week so I guess it's a "wait 'n see" if he/she does. Top must be UP and there's no current concern maybe. LOL

kg4fku

Yup! I love it when OP's don't follow-up on their posts.

My little rant.

I have no problems helping fellow members where I can and I appreciate any help I receive as well.

We tell everyone to utilize the search function for common issues but when they do, more times than not, they find these unanswered, dead-ended threads that have no final resolution. So we all end up in a constant loop of questions and answers with no previous history to fall back on.

Long story short is that OP's need to close out their technical issue threads with what the final solution was, if there is one, so future questions can be referenced back to them.

OK. I am off the soap box.

txnese

Sorry to every one that I haven't checked back and responded sooner, darn work stuff has been getting in my way and I haven't had a chance to get back to playing with the cars. Finally got to it a earlier this week and pretty sure we've found the problem. Looks like latches for the convertible top lid didn't get pushed down far enough to close the switch and the interior lights (or something) was drawing the battery down. In other words, user error. Thanks again all, from here on out, Corvettes take priority over work.