Ned Kelly
1/2 ton status
My old alternator was putting out less than 11 volts, so I picked up a new one. After I installed the new one I measured the output at 15.1 volts. Is this too much and will it 'cook' my battery? 
CK5
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15.1 volts too much alternator output?
- Thread starter Ned Kelly
- Start date
Fierospeeder
Banned
should be fine. Just make sure it doesn't start getting any higher
I'm not sure, but the highest I've ever seen mine at was 14.3 or so.
Rene
Rene
84_Chevy_K10
Banned
I'd say that you have to have a short somewhere or something to be putting that kind of load on an alternator, unless the voltage regulator is messed up.
Mantruck-k5
Registered Member
Sounds too high
Mine currently reads 14.9 so I started investigating. I read on a tech sight that below 13.5 at 2000 RPM is too low and above 15 volts at 2000 is too high. Sorry but I can't find the link again.
Do you have any electrical equipment that pulls a ton of voltage?
Also, next time you might want to consider rebuliding your alternator instead of buying a new one. It's cheaper and fairly easy but there's no "lifetime" guarantee.
Mine currently reads 14.9 so I started investigating. I read on a tech sight that below 13.5 at 2000 RPM is too low and above 15 volts at 2000 is too high. Sorry but I can't find the link again.
Do you have any electrical equipment that pulls a ton of voltage?
Also, next time you might want to consider rebuliding your alternator instead of buying a new one. It's cheaper and fairly easy but there's no "lifetime" guarantee.
Mantruck-k5
Registered Member
Fierospeeder
Banned
Im assuming his battery is close to being completely dead when his old alternator wasn't charging. So the new alternator sees a battery that is very drained.
Even with a heavy draw like a near dead battery, the voltage regulator should prevent the output from getting to far out of the range.
When my last alternator went I had short periods where the voltage would spike to 18 volt+ (driving at night...very bright headlights
) and then it would drop down to normal. Eventually it packed it in.
When I had a dead short it also did the same but even worse, supplying so much voltage it burned out all 4 headlights in under 15 seconds.
I'd be a little concerned with 15.1 volts...maybe enough to bring the alt back.
Rene
When my last alternator went I had short periods where the voltage would spike to 18 volt+ (driving at night...very bright headlights
) and then it would drop down to normal. Eventually it packed it in.When I had a dead short it also did the same but even worse, supplying so much voltage it burned out all 4 headlights in under 15 seconds.
I'd be a little concerned with 15.1 volts...maybe enough to bring the alt back.
Rene
Ned Kelly
1/2 ton status
I know 15 v is supposed to be the outer limit for 'ok', so 15.1 crosses it by a hair. The battery is fully charged and at no load it still cranks out 15.1 volts. I'll take the alternator back and get a different one just to be safe. Thanksf for all the info guys.
