battery goes dead twice but auto electrician says there's no problem??

[no idea]

hey all
my '93 executive VP keeps turning on the battery warning light and the battery went flat leaving me in the kfc carpark.
The car has a reasonably new battery so i thought the alternator was on its way out so i got myself a replacement one which was in much better condition but somehow the battery light kept coming back on and then the car died again (this time in the macca's carpark...maybe its telling me something)

so i handed the car to an auto electrician, he sed he tested everything and found no problems at all

but the battery light keeps coming on anyway

has anyone else had this problem and if so what turned out to be the cause??

PS: nothing has been done to the electrical system everything in it is still stock

[Morton]

It's possible that it could just be time for a new battery. Get yourself a good expensive Bosch battery, they can take all kinds of punishment. I leave my car running stereo equipment for hours at a time, and she always cranks first go. It's possible that if your battery is past it's useful life, it can't hold charge anymore.

Alternatively, there could be a ground issue from your alternator. A ground could be getting rusty, or lose.

[voney]

Check for power "leaks", ie lights that stay on even when the're supposed to be off.

I had an issue with the boot light being on all the time because the boot kinge was not contacting the switch properly.

[VS_Pete_1]

Could this be the problem MYBE??????
The charging lead
VS v6 owners check this out

[VRAddiction]

well it sounds like an auto elec who doesn't know what hes on about to me

[kovini]

id agree with ^^, another dodgy operator.

check out the voltage at the battery with the car idling. should be over 14.4, or the alternator is dodge.

If thats all fine, then check things like your STEREO, assuming that it's not factory, and check that the yellow (12v direct line) is not crappy, etc. ... and move on from there.

Also check your battery terminals are OK, and that your grounds are ok. (surprise, like they said)

[voxbox]

if you're getting a fault light coming on it's going to be something to do with the charging system. As kovini said, check the voltage at the battery at idle, should be around 14.4V. If it isn't, either the alternator, or the voltage regulator is dead. If it's over-volting the battery(15+ V), it's going to screw it in a matter of hours. If it's under-volting(less than 12V) then the battery isnt being charged, and is simply expelling all its stored energy before going flat.

[aussieghostrider]

yeah as voxbox said there is a regulator on the alternator that I have had replaced once ..

you know its that cause if you have a good sound system thats chews the juice ... you will have power fluctuations at night time if you have headlights on ..

the lights will dim then go bright and so on ... with headlights , dash , radio etc ... cost me like $100 to have fixed ...

If your short of cash then I suggest you dont drive at night and dont use your stereo ..