Put clb in 2003 Z06 two weeks ago, had to charge up dead battery then. battery is 3 years old. Have had to keep charging battery up this past year due to lack of use. Tried to crank up today, only had 10.5 volts, dead again. When I disconnect battery ground there is a spark and I hear a relay clicking under the R headlight. Disconnected the lead to the headlight motor, no change. Is there something that's supposed to be energized down in that area or what? Original battery lasted 3 years and it died real quick.

Your thoughts and suggestions please!

 

There is often a click from the head light area when you disconnect the battery. There is also usually a small spark when you disconnect the battery. Both conditions by them selves are normal.

A couple of different things may be going on here. The battery may be bad. You need to have it load tested after you have fully charged it to know if it is bad or not. Most auto parts stores do that free of charge.

You may have some electrical component in the car that is causing an abnormal current draw when the ignition is off. This results in the battery going dead in a short period of time. To isolate this you need to do some testing. The procedure involves placing an ammeter between the neg. battery cable and the neg. battery post. Then you need to start pulling fuses and watch the change in current draw. In sleep mode the draw should be about 20 ma. or less. Here is a link to a list of the typical components that fail that you can start with:

http://forums.corvetteforum.com/c5-t...goes-dead.html

Then scroll down to post #9.

I'll look up the post the thread that explains in detail with pictures how to go about isolating the current draw using the ammeter technique.


Here is the link into the Bill Curlee "Electrical" stickey at the top of the TECH forum that talks about finding an electrical current drain:

http://forums.corvetteforum.com/c5-t...n-long-30.html

Then scroll down to post 590.

 

Every time you allow a non-deep cycle battery to discharge that low, you take away some of it's life. I've found that each occurance can chop off 3 months or more of life. When the battery is low enough so that there is insufficient current to start the engine, you may very well hear some strange clicking/whirring noises. Remember, if you let your car sit for more than 2-3 weeks at a time, it's best to hook up a maintainer (like the battery tender plus) to keep the battery at full charge.

 

Appreciate help. Got battery recharged and started on diagnostics, but it's getting dark and cool (for a Florida boy). Will restart tomorrow.

 

You already had some great advice but there may be nothing more sinister than a battery that died young. What you describe are classic dead battery symptoms. The relays chatter when the battery is low on charge.

You don't say what type of battery you have fitted - lead/acid or AGM (Red Top)? Also what type of use does the car get? Is it a DD or does it just come out occasionally? All of these things affect how you should look after the battery.

If there is a drain you'd need to find it. It might not be a good idea to fit a new battery until you do. On the other hand, a battery that's on its last legs may recharge now but fail at some point. An AGM that has been coaxed back to life is on borrowed time.

 

As a battery discharges lead sulfate is deposited on the plates within the cells of the battery.
When the batter is charged the sulfate dissolves and is turned back to lead.
The problem arises when the discharge period is longer than the charge period... That means the sulfate deposit gets thicker and thicker... eventually it is so thick that is becomes insulative in properties...
The battery cannot the accept or hold a charge....

Always keep a seldom driven vehicle on a battery float charger...

 

Thanks everyone for help. Took 2.95 year old lead acid battery to Advance Auto and test showed marginal, so I got a free replacement. Glad I didn't wait another two weeks. Did the load testing as recommended, it started out at 1.2 amps, then dropped to 0.2, then 0.07 and finally to 0.01 amps after about 15 minutes using 10 amp scale. The hood light would kick it back up to 1.2 amps and it would take it another 10 minutes or so to drift back to the 0.01 amp level.

Funny thing about when I was doing the CLB two weeks ago. In the middle of everything the fuse box on passenger side started sounding off like a mariachi band, I thought I was burning something up for sure. Turns out the battery had just dropped to a crucial point and a bunch of relays started clicking away. Got my attention!

Again, thanks everybody. Need to drive the car a lot more to cure the dead battery problem. Weather is great in FL today, will go to crap over the next week.

 

yes...drive it more!!!!