weird charging problem
weird charging problem Ok, so my alt after warming up wont charge more than 13.5 volts. I assumed it was a bad alt. so i got one from a buddy that was working when he took it off. Same problem... brought my alt. (off car) to autozone, tested as being good. Put alt back on (with new battery) and everything was fine for about 700 miles. Now I am back to only charging 13.5 volts. i have checked all the grounds and they are all good and tight. What the hell could this be? Its driving me crazy!!
So whats the problem....?
Is the car having trouble running or are you getting a battery light? If not then dont worry about it. Most GM cars charge at 13-14 volts. Also, its the amps you need to really be worried about not the voltage. If you had it load tested and it passed then your good.
Is the car having trouble running or are you getting a battery light? If not then dont worry about it. Most GM cars charge at 13-14 volts. Also, its the amps you need to really be worried about not the voltage. If you had it load tested and it passed then your good.
13.5 is normal.
I have a battery digital volt meter does the same as the one we got on the dash. My the highest its gone is 14 maybe 15 volts but only for a few seconds then it'll drop to 13 or somtimes 12. Nothing to worry about.
I have a battery digital volt meter does the same as the one we got on the dash. My the highest its gone is 14 maybe 15 volts but only for a few seconds then it'll drop to 13 or somtimes 12. Nothing to worry about.
TECH Enthusiast
Joined: Dec 2005
Posts: 510
Likes: 0
From: NW burbs of Chicago
The dash voltmeter is not accurate. You should check at the battery with a good handheld meter and tell us what you find.
This is what I would expect to see:
1. Car just turned off after running about 12.5 - 13
2. Car running about 13.9 - 14.2
3. Car off headlights on high beam about 12.2 and dropping very very slowly.
This is what I would expect to see:
1. Car just turned off after running about 12.5 - 13
2. Car running about 13.9 - 14.2
3. Car off headlights on high beam about 12.2 and dropping very very slowly.
i understand that dash is not accurate, thats why my posted results came from a good meter 
i have been told by two bmw mechanics and one gm mechanic that it should be charging no less than 13.8 while running. thats why im concerned
i have been told by two bmw mechanics and one gm mechanic that it should be charging no less than 13.8 while running. thats why im concerned 
TECH Senior Member
Joined: Dec 2001
Posts: 5,399
Likes: 3
From: Jacksonville, FL
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