Hi my 99 maxima automatic is over charging 15 volt. 14.5 with ac on high and radio on. New battery. Previous owner replaced alternator 8 months ago. I removed alternator had it tested at auto zone and oreilley and it tested good at both places. I checked fuses and they are good. I can't figure it out. Any advice would be appreciated thank you.

 

We've had a few Alternator threads lately. I'd suggest reading up to validate what I will; say........

Aftermarket new and rebuilt suck for our cars. Just like starters. the only one that has a chance of performing as good and long as the original Hitachis are rebuilt Hitachi from Hitachi. These are a PITA to swap out so Limited Lifetime Warranty doesn't make swapping OK.

My original lasted over 170K and wasn't bad when replaced. I had other electrical problems and the mechanic threw parts at it. Bosch went in twice. The last one lasted 2 to 3K miles. Both brand new. Htachi ALR0011 now.

A few are lucky with AZ and Advanced LLT warranty stuff, but the failure percentages are too high across the board.

Your voltage regulator (in the alternator and not replaceable) is failing and will take the battery with it before it fries.
If you pay a mechanic, do it right the first time. Hitachi. And look for a sale. Stupid expensive.

 

I put in a rebuilt Hitachi 50,000 miles ago and haven't had any problems with it so far.

 

Same here, I found a completely new oem nissan alternator at the junkyard in a infiniti i30 and its been almost 4-5 years and still working flawlessly. Dont ever go oreilly or autozone as you'll be replacing them every year.

 

The alternator should be at and around starting 13.8-14.5 no more or less than this i know that 15.0 is to much and it's over load and it's way up their alternator is failing along with the battery that's gonna get hammered in the process. I was at 14.5 with all the loads or no loads i was at 14.2 this is a very health peak. If your at around 15.0 that's very bad and high your risking to short the electricals and the computers of the cars.

 

15 volts is too high for any car. Where ever you had it tested at, don't use them again.

 

Optimal is 14.6-15.2 volts. You're perfect.