replaced the alt last year after it started overcharging on the way back from a camping trip. aftermarket gauge showed it bouncing between 16 and 18 and factory just held steady at 17. been fine for a year till a few weeks ago i came back from the same camp trip and the same problem came up...what's up with that?
CK5
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alternator overcharging?
- Thread starter keelue
- Start date
Don't go camping there, obviously. 
Get thee a digital voltmeter, check the voltage at the back of the alternator and at the battery positive.
One possibility is that the regulator, internal to the alternator, is crap, so you either replace the unit or have it rebuilt.
Another is that the wiring or connections are corroded or are otherwise introducing resistance, so you may see like 15V at the back of the alternator ... but only 14 or 14.5V at the battery. Should be almost identical across the system (a coupla tenths variance is fine.)
Dash gauges are notoriously innacurate, which is why I suggest the DVM. That and they're cheap and oh so very handy for so many things on the truck or around the house.
-- A
Get thee a digital voltmeter, check the voltage at the back of the alternator and at the battery positive.
One possibility is that the regulator, internal to the alternator, is crap, so you either replace the unit or have it rebuilt.
Another is that the wiring or connections are corroded or are otherwise introducing resistance, so you may see like 15V at the back of the alternator ... but only 14 or 14.5V at the battery. Should be almost identical across the system (a coupla tenths variance is fine.)
Dash gauges are notoriously innacurate, which is why I suggest the DVM. That and they're cheap and oh so very handy for so many things on the truck or around the house.
-- A
thanks, i'll pick up a digi this weekend and see. i'm sure the alternator is under warranty so it's not a big deal i just have never had this happen on any vehicle before. didn't know if something outside the alt could be causing it (other than the buddies i go camping with)
shaun89
1/2 ton status
i no this is probably not the issue,but ill say it incase someone searches this in the future,i had an alternator issue a year ago,it kept overcharging and i went through like 3 alternators before i learned that inside of my battery the POS/NEG cells were mixing. so i got a new battery and it solved it. good luck with ur issue
