Thread: A new one - battery voltage drops when car starts.

Originally Posted by drivesafe

Hi Dagilmo, do you by any chance know how low your battery was discharge to?

Hi Tim,

Unfortunately, I don't know. I arrived at work and could smell burn electricals. Thought, "I wondered whose car that is" only to have smoke coming out of mine when I parked. Flat bed to Rovertech, new alternator and told battery was cactus also. I kept the battery as I wasn't convinced (no reason not to be, but my brain couln't reconcile a near new battery being stuffed) but I've never had it tested. Though it did come in handy when we lost power for a couple of nights and I rigged up 12v camping lights in the house....

Cheers David.

When the alternators fail in these cars, the battery can short straight to earth through the alternator (hence the burnt electrical smell) - so not an issue of low voltage. When my alternator failed last year I was told I would need a new battery but mine did not short and the battery was still able to run the car - albeit with every fault known to man showing and things coming on and off all by themselves but the engine still ran.

Even after 40km driving to the indy and back just on the battery it was still over 12v - I was lucky as most do the battery as well.

Garry

Originally Posted by trout1105

In my experiance by the time someone finally works out that their alternator is buggered the battery is also toast as well.
Replacing only the alternator and leaving the defective battery in the car Must have a detramental effect on that new alternator.
A new battery is usually only a fraction of the price of a new alternator and it makes good sense to replace the battery when you fit a new alternator

I think I caught mine early enough, replaced alternator within 2 days of the error code and didn't actually drive the car after getting the code