Have a year old Optima battery that dealer tested and says is good. Battery drains overnight, down to 2 volts. Wondering if there is any common issue for battery drain?

Backstory- Windows leak terribly (2002 ZO6). Have to keep it covered during rain, a real chore in Florida. Went out of town for three days and cover blew off. The entire interior had droplets of water like heavy dew covering it. Dried out with dehumidifier and issue started day after. Nothing else changed, other than it hadn't been driven in about 10 days.

Car is making me crazy, it's always something. Have dumped far too much into it to keep having problems. That's why I'm asking if there are any common problems anyone knows about.

 

I don't know if Z06s have memory seats but that has been the source of a lot of battery draining. That said...

Set up a multimeter to measure the current draw from the battery with the engine off. After about 15-20 minutes it should drop to approx .002 amps. Almost nothing. (mine did, I'm so proud of her)

If it is higher then start pulling fuses to various circuits until you see it drop. One of the items in that circuit is the culprit.

I don't think there is any other way.

 

There is a better and faster way to find a parasitic drain…sometimes pulling fuses can sometimes wake up other modules causing a misdiagnosis…watch the video..a voltage drop check on each fuse makes it quicker…a bad diode in the alternator can also cause a drain other than a module…having a battery that goes dead like that shortens the life of the battery considerably !!…it may be the drivers door module getting wet so I’d concentrate on that module.

 

Here's the current draw charts.

 

Thanks for all the info so far. The driver's door has the worst leak by far. No doubt water got at it at some recent point.

Wife has given me weekend projects, so next week before I can start troubleshooting.

 

Checkout this thread for responses from Bill Curlee. Bill is a c5 electrical system wizard.

https://www.corvetteforum.com/forums...er-3-days.html

 

I had this overnight dead battery problem many years ago. Turned out to be a bad BCM. Follow C5diag's advice. Him, Bill Curlee, MMartinez, GCG. ALL know their stuff on electrical. Which is great if you own a C5, because there has to be 3 or 4 miles of wiring in them!!!

 

I have had two instances where my battery drained overnight. The first one was because I left my ROAV IPhone charger plugged in the center console. The charger lights up when plugged in causing parasitic drain once the ignition is off. The second time was when I had accidentally turned the dash light brightness control all the way clockwise turning the interior lights on the rear area of my Z06. I have an aftermarket partition to make a “trunk” space. The partition keep me from noticing the lights staying on.

 

A common cause of battery drain is a bad seat switch. Until you can do the battery drain test as Bill Curlee describes or C5 diag mentions, an easy move would be to pull both seat breakers in the passenger side fuse center.

Perhaps five years ago my car had sudden battery drain caused by a bad driver side seat switch, narrowed down by pulling the seat breakers.

 

Update: I have been plugging away at the problem for too long. I found nothing any place I checked and decided to see if the regulator was bad in the Alternator. Nobody local seemed to be able to test it, so I replaced the whole thing. It seems to have ended my nightly drain.

Now, however, it is giving me odd readings. I check the battery with a meter at the battery and it shows 12.2 volts. Turn on the ignition and go to the voltmeter and it says 11.4 volts. Car starts normal as if it has full voltage, and then gauge goes up and down like normal when I drive. What in the world is this thing doing now?????/

 

The only thing I suggest is that you examine the cable connections at the starter solenoid making sure they are clean and tight. This is where the alternator output wire connects to the battery.

 

What is the voltage across the battery terminals with the engine running? Should be above 13 volts, probably 13 1/2 to 14 volts when the alternator is charging.

Voltage across the battery terminals NOT running?

With the engine NOT running and a fully charged battery, the voltage across the battery terminals should be about 12.6 volts.

 

Running has been around 14.2 volts at terminals. Engine off is 12.2 volts, brand new battery (might need some driving to push it up the last fraction of a volt). But battery was on a smart charger as I waited for parts.

 

12.2 volts is about 55% charge.

 

Best method to diagnose a draw !!…where are you located in Florida ??…if you’re near the Southwest bring it by and I’ll take a look at it !!..it’s a good idea to include your location in your profile because help may be just around the corner !!

 

Found it already, wanted to post up a close to the thread in case somebody else ran into problem later. It was a bad regulator in the alternator. Now I just have to fix the fuel door that won't stay closed, replace the driver window regulator and outside mirror. Not to mention that the dash radio has now refused to play CD's anymore....but at least I have parts to fix it all. But can't control the rain...!

 

My parasitic drain turned out to be a map light on the rear view mirror left on accidentally. I would have thought that this light would have timed out with much of the other systems, but not the case on my 2004 LeMans Commerative Edition. I replaced the original battery unnecessarily in 2013, and it was only 9 years old!! I just knew that due to age that the battery was the source of my trouble, but after installing a new one I found the following morning that I was wrong! Took me a while to find the source of my problem, I just put a trickle charger on for a while before I got around to troubleshooting the fault. Then, a week or two before I started troubleshooting I saw the small dim light shining from the mirror on the back of my hand as I was reaching for something in the direction of the mirror. Punched the "off" button on the driver's side of the maplight and never another problem.

I susbsequently installed a GHSHLS rearview mirror in the place of my original since it had a rearview backup screen in the mirror, a vast improvement over the original factory mirror. Includes backup camera, compass, auto-dimming, etc., but no map lights. I solved the lack of map lights, which I seldom/never used anyhow, by turning the visors all the way down and against the windshield such that the vanity mirror is on the downside of the visor. Now, should you need a map light, just flip open the vanity mirror lid and the mirror serves the same function as the original map light. I think it may even be a bit brighter than the map light, not for sure since it gets little to no use anyhow. And, as an added bonus in my opinion, the visors are much better protected against wind and bug damage with the top down, and there is no visibility restriction out the front windshield. The visor covers little more than the sun shaded portion of the windshield anyhow.

I did add one item to the car that I also felt the car should have had as original equipment that draws current even after shutting off the ignition. My car did not have the optional CD changer mounted in the rear center storage compartment, which I would have never used anyhow since the factory system won't play MP3's or WMA, or other file types. And I wouldn't bother changing the CD's frequently enough to be of benefit to me anyhow. I did find out however that one can install a device called an I-Simple that is about the size of the small matchboxes that were once common, and that a cable from the device can be connected to an IPhone or IPod containing any music you choose to load onto the device. I am using an IPod Touch and have located it behind the cigarette lighter and ash tray door, having removed both the lighter and ash tray. It fits neatly behind the door and holds MANY MANY of my favorite 50's and 60's tunes, as well as a few (50 to 100) from the 40's. The AUX button on the factory radio is used to switch from radio to CD changer, just as with the original CD changer in the trunk, and the factory radio thinks the IPod device is the original CD changer. Buttons on the radio such as NEXT work on the IPod device just as they do on the original radio and thankfully I'm not limited to the few original CD's available on the original. I just leave mine to select songs at random, and on a recent trip of a couple of days the wife and I were just getting in a bit after sundown when a Roy Orbison tune came on. I've got several albums by Roy stored on the IPod, but we both commented that this song was the first by Roy that we had heard in the two day outing. I don't think it repeated any of the songs played during the trip, this thing is great. But, it will continue to draw a bit of power after shutting down the car unless it's unplugged. So, rather than bother with unplugging I just put a trickle charger on the car when it may be 2-3 days or more between drives. Works for me . . .

Ron

 

It's worth a little parasitic drain to support a pretty woman.