I have a 12-month old AC-Delco Absorbent Glass Mat (AGM) batt in my 2000 C5. This car is not my daily driver, and will on occasion not be started/driven for 7-14 days. This evening I went out to start the car after 10 days of "rest" in the garage and there was not enough "juice" to turn the engine over. This has happened several times after similar periods of non-use. I'm no battery expert, but I've never had a battery drain so quickly in any vehicle I've ever owned--this doesn't seem right. Is there some electrical system/device/?? that continues to be "on-line" with the ignition off that could draw enough current to drain the battery as I have described above. It's not a "sticky" interior or underhood light, and I have no "extras" installed that draw current.

I've not hooked-up my volt-ohm meter to calibrate the drain, so can't provide any info in this area. Thanks in advance for comments/suggestions/recommendations.

 

Install a Battery Tender and it will always be ready to go. Unplug from the AC, turn the key and on your way.

 

my car is alway on a Battery Tender because i take my vette only on week end and she always start very well

regard

 

Battery Tender

 

Get your battery tested first, you may have a bad cell that is shorting out. A fully charged battery should not drain down after 14 days of "resting". Then if that turns out not to be the problem, I would take the positive or negative lead off, put your volt ohm meter on to read current with a range of say 10 to 20 amps and see what it is drawing with nothing turned on. (Since the hood is up, turn off the hood light) If you are drawing current, start pulling fuses one at a time and keep an eye on the current draw. Eventually, you will hit the circuit that is draining your battery. That will at least narrow the problem down to the point you may be able to find it. Good luck.

 

There can be many causes of drain, and to isolate them you need to have a basic understanding of using a voltmeter. If you don't have the time or experience, a battery tender may eliminate the frustration of a dead battery for you.

If you do want to trouble shoot it I would suggest PMing Bill Curlee and Patches for tips - they've good with the electrical stuff....

 

Hasn't leaked any acid out has it?? My $.02

 

AGM batteries are leak and vibration-proof. My OEM ACDelco AGM battery is now more than 4 years old and it still starts my car like the day it was new. AGMs do NOT like to be deep-cycled (drained well below their reserve capacity), so by all means, hook up a Battery Tender Plus when your car sits for extended periods.

 

Thanks for all the responses/suggestions. This continues to be an amazing and well-run forum. I'm mostly a reader now; it was invaluable when I was considering my C5 purchase, and during my "outfitting" days.

 

I have let my '04 sit for 10 days straight. Starts right up.

 

Your car should be able to sit 30-60 days at a time without a problem!!! Something is wrong. Your best bet is to use an AMP Meter and determine how much current the car draws when it is off and the electrical system goes to sleep.

I went out to my 02 Z06 and took the readings just a few minutes ago!

Disconnect the negative battery cable, install an AMP Meter capable of reading at least 10 amps between the battery terminal and the cable.
Negative meter lead on the negative battery terminal and positive lead on the negative cable.

Make sure that everything is off, shut and secured anything that could give you a false reading i.e. doors shut, trunk shut, hood light disconnected ect, ect...

Here is the hook up:



The amp meter will read high at first. When you connect the circuit you will hear a relay in the engine compartment click and the amp meter will jump up to around 8 amps, then immediately fall to 2 amps, then fall to .35 amps and then it will settle on .09 amps for approx 2 min. After the 2 minutes it should drop down to around 0.02 to 0.04 amps.

Here is the finial reading after the car went to sleep (approx 2 minutes from time to circuit connection to finial reading)





There are many things that can cause excessive current draw. Take the readings and let me know what you see.

Bill Curlee

 

was your alarm on? Mine (98 Vert, now gone) has set for as long as 6 weeks with no battery problem. I park it without car alarm set in my garage, no problem. I am going to get a maintaince charger for my C6. Heard too many horor stories.

 

with Bill Curlee! I couldn't post pictures but Bill's procedure is exactly what I was suggesting you to do. After a few minutes if you are still reading more than 0.02 amps, then open up the fuse box under the passenger floor board and start pulling fuses one at a time, then put it back, until you see the current draw drop way down. If you have an aftermarket alarm system, stereo amp, anything that is not stock, check that first. I once had a stereo amp stay on after the head unit was turned off and it drained my battery down. Good luck and let us know what you find.

 

I try to post factual and correct post! Sometimes I over look some of the factors that can change things. Now your going to make me go back out and take readings with the alarm set!

You have my curosity raised. I have herd this theory on one other post a while back. Give me a few minutes and I will re do the test with the OEM security system set (FOB LOCK).

Bill Curlee

 

Well,,,, I just shot that theroy to hell!! I did the same test and let the PCM and BCM circuits go into sleep mode. Current draw= 0.02 amps. I locked the car with the FOB and it basicly did the same thing reading wise: 8 amps, 2 amps .35 amps .09 amps amd them it went to 0.02 amps after about 2 minutes. So,,,, the OEM alarm circuit does NOT draw any more current than in the NON alarm mode.

Unless I'm not doing something with the alarm mode that you are, that is how it stacks up.

There may be differences in current draw from year to year and differences in OPTIONS from car to car. I did the same test on my 98 MN6 coupe a few years ago and the lowest reading that I got was 0.04 amps. Not a hugh difference but there is some. Either car could sit for MONTHS and never had a battery issue!!\

I'm very interested in the current draw readings that vettemanjj gets!!

Bill

 

This place is awesome ...

The people here make it so.

(except that one guy)

 

Thanks for checking out the current draw with alarm on. I was only trying to help out and reported my findings about car starting. I never had a battery problem and thought it might have something to do with it. My car, far from a DD. never experienced a low battery. The low battery thing was a constant issue on the C5 registry for years; guess I just had a good car. FWIW hope my new C6 does as well.

 

I discovered my glovebox light was not being turned off by the switch when the door was closed, and had to adjust the switch to correct it. It's difficult to see it,(it's kind a cramped in there)LOL.

 

This is great info. Bill, thanks for all of the tips. My original Delco battery lasted 18 months before I started getting low voltage messages whenever the door was left open when doing work or cleaning the car. I bought a Optima red top in Sep. 2003 and now it is starting to do the same thing. It looks like it is time to check the current draw.

 

I had a similar situation with my battery. The original battery lasted 16 months went out and purchased a optima red top from autozone. They sold me the battery with only a partial charge. I too it back because it wouldn't start the car they gave it a full charge. Next day the car barely started. I took it out for a 5 hour ride thinking that would fully charge the battery. Next day I had the same problem again slow start took the car to the dealer. Come to find out the new optima had a dead cell . Then I had to convince the autozone guys to exchange the battery which they did. Put the new battery on a 60 min high charge let the car sit overnight . Turn the key today and car started with no problem. So beware just because the battery is new dosen't mean there may not be something wrong it.