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ahanlov 12/3/2018

2006 Pontiac Torrent Base 6 Cyl 3.40L


Could a bad battery cause alternator failure?

'06 Pontiac Torrent AWD
I made the mistake of leaving my key in the ignition in accessory mode for about 8 hours while at work. Returned to find my car completely dead. Charging with jumper cables and attempting a jump start didn't engage starter, so we thought starter might have gone out. Bought and installed new starter - were then able to hear clicks, but still no start when car jumped.
Bought new battery and installed. Car fired right up! But, the battery light was on indicating charging system failure. Belt in tact and water pump working, etc, so good there. Car needed to move, so managed to drive it home at night w/ no issues. Headlights, radio, all worked for that 15 minute drive. Car started in morning just fine, so drove to work.
Headlights and accessories flickered 1/4 mile from the office; managed to coast on low power into lot. Replaced alternator a few days later but battery light still on.
Can a partially sulfated battery cause alternator issues? What else could it b

1 Answer


Jimm 12/8/2018

A battery with a short in it will cause the alternator to run at full output for extended periods of time, if not continuously - and they are not built to do this. Alternators the world over are built to supply an initial high current, tapering back as the current used to start the vehicle is replenished. Constant running at full output simply overheats them and the rectifiers fail.

If your battery is 'Open Circuit' the alternator will either not start charging at all or will erratically bounce from low to high voltage. This causes the regulator to fail prematurely (or immediately!)

A battery that simply will not accept charge won't necessarily cause premature failure of the alternator unless it is permanently at a low voltage.


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