I have on '05 and for the first 6-7 years I had no problems with the battery. I then started having what appears to be the old DBS and have gone through several batteries and several flashes as the techs tried to identify the problem, which of course they never did. Don't get me started on that though!

The present battery went through one or two deep discharges in the month or two after I first bought it and before I gave up and just bought a battery tender. From the outset, when I drive the car into the garage and hook up the tender, it has always gone "red" showing that it was needing to charge the battery for awhile even after driving extensively. It also comes on for a bit now and then to bring the charge back up. I have thought it odd that it needed a significant charge after driving but expected an infrequent "top off" charge while hooked up and not being driven.

Yesterday I noticed the tender light was red and remained that way, and the transformer/tender is pretty warm so I think it is charging pretty heavily. I disconnected the battery to check volts/current. Initially the voltage was 13 but dropped to a bit over 12 while I was testing it. The current ran about 3 amps or better initially after disconnecting the battery and inserting the meter, but dropped to a steady state of about .2 amps after a bit. That seems high to me but I don't really know what to expect.

Are there any knowledgeable people here who can offer advice? I don't want to just buy another battery without knowing if there is likely a failed solenoid, module or something. There does not sound or look like there is anything still active after a minute or so. I have given up on finding a competent chevrolet mechanic in this entire state. Comments appreciated.

John

 

The desired, completely shut down which occurs about 20 mins after turning everything off, draw is 18-30 milliamps. It seems many cars that have a problem report a draw of about 100 milliamps with some much higher.

There are many possible causes, as simple as clipping a garage door opener on the visor pressing the Homelink button to defective modules and radio turning on intermittently.

It really takes a methodical diagnostic approach to find what it is. Set up a draw test and watch for sudden unexpected draw, start pulling fuses and relays to see what stops the draw and identify the offending item.

Here's a lengthy discussion with some good info. The detailed info starts at post 77. Good luck.

http://forums.corvetteforum.com/c6-c...-syndrome.html

 

Rick,

Thanks for the help. After reading your post I took a better, digital meter outside and have much more realistic readings. After initially inserting the new meter, the current was only about 35 ma and dropped fairly quickly to a steady-state 13-14 ma so that is much more consistent with the data in the link you provided. I'll go out now and then to see what I can "catch" but I don't want to stare at it for an hour. I'm thinking the battery may just be bad and requires a constant charge from the tender at this point since the car seems to be drawing an appropriate low level current. Thanks again.

John

 

certainly no expertise here, but if the batt. was still low after driving, could it be an alternator problem?

 

Your 13 ma is consistent with my car at rest. I get 11-17ma after everything settles down. 100ma is too much and indicates a problem. I think you are right that your battery is just bad. You can measure the current going into the car from the battery tender also. After everything settles down, my tender puts in right at 25ma, which makes sense, say 15ma for the car's electronics and 10ma into the battery to keep it at 13.5 volts.

 

It surely could be but it seems to be charging and I have had the system checked. These gremlins are a nightmare.
J

 

FWIW, my CTEK 3300 (Corvette model) tender always shows charging for a while after I plug it in, even if I just finished a 4 hour drive. It goes green sometime between 30 minutes and overnight, depending on ???

 

If the battery has been discharged several times it should be replaced. SLI batteries are not made to take deep discharges.

 

you did not mention that you checked the output of the alternator. what does it read when driving? it really need to be running over 13.5 volts to keep the battery & car alive. I also have a Cetek tender and I plug mine in if the car will spend more than 2 days not being driven. I am lucky and haven't had battery problems, but i did loose an alternator early for no reason, voltage would drop to 11.5 & everything went nuts. your current draw seems to be correct so i'm leaning towards an alternator or connection problem.

good luck

 

My Battery Tender always shows a red light when I hook it up after even a long drive and then turns green after a short time. My C6 is a 09 with the original battery which has given me no problems.

 

think about replacing the door switches, the pads you grab to open the door from the outside. My Passenger one was waking the car up over and over thus killing my battery