High RPM Poster
Jan 27, 2009
Sherwood Park
2001 Z06
Hey guys... question for the resident people that know more about this than myself...

A little while ago, my car was inexplicably dead. I boosted it and for 6 weeks or so it was fine. Then on another day after sitting for 4-5 days it wouldn't start. The battery was never totally dead... just got the click click click sounds from the starter. I boosted it again.

The other day again... click click click.. I boosted it. I drove the car for 2-3 hours and then stopped at the gas station. When to start the car... click click click.

Once when I started the car I got a temporary message indicating a charging system error but it never came back. When I look at the battery volts while the car is running it was always between 14.1 and 14.4.

I find it hard to believe that there is a drain when the car isn't running because the battery was never bone dead dry at any time and it couldn't be the alternator because of course the car would just slowly die over a period WHILE it's being driven. There were no issues while driving the car at all.

The interesting part is that the battery is only 18 months old (Exide). I never removed the battery last winter but the car was in the garage (NOT heated) and I started the car every 3-4 weeks.

I already bought another battery for it but I haven't installed it yet.

Any thoughts on this from anyone? I figured it was cheaper just to buy the battery and give it a try than to take it to GM and have them charge me $200 to diagnose the issue as being a defunct battery.

Thanks in advance!!

Tony the battery my not be completely dead , but it will not have enough amps to crank over the starter . Check the battery with the engine off and see if the voltage drops . If it does than it is not holding the charge . Go buy yourself an Optima Red Top :D

Hope that helps .

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Also buy a Hydrometer---and check every cell. One bad cell can give you very intermitent starting and electrical gremlins while still showing good amps--unless you check under load. I have taken a battery back to Canadian Tire--set it up on the tester--Tested OK---asked the guy to borrow a Hydrometer--bingo--one cell down--Canadian tire buys me a new battery under warranty. I wonder how many people they have said "No problem" too and sent back out the door.:seeya:
When the car is running you should get 13.6 and 14.5 volts at idle to get a proper charge voltage on the battery.
If the alternator voltage is less then 13.6 volts you might have a bad diode in the alternator and it will never charge
the battery to full.

You can also show a voltage but have a bad diode that will give you a AC signal. You can measure the DC voltage
then turn your meter to AC and see if there is any ripple. If you have fluctuating AC then there might be a bad diode.

The battery voltage when full charged should be 12.5 and 12.8 volts when the car is turned off, if less then that it might
not be full charged or if its never more then 12.5 volts then you could have a bad cell etc.

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