Truck's Voltage

A forum for the legendary Nissan Pathfinder and Infiniti QX4.
RoyDaGeneral
Posts: 140
Joined: Wed Jun 05, 2019 10:55 am
Car: 2002 Infiniti QX4 2WD
Location: Berkeley, CA

Post

I recently changed my truck's alternator and battery coz while driving I was getting voltage readings in this range: 12.3-13.5. I was also hearing an unsettling noise coming from under the hood when voltage dropped down to 12.5 or below, and as I read up on bad alternator symptoms, that type of noise was mentioned as one symptom. After replacing alternator and battery, I'm now getting voltage readings as high as 14.2 and mostly in the high 13s, but I've experienced readings as low as 13.4 as well. My question is: why am I getting occasional low voltage, 13.4? Is this normal and what is the normal range?


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VStar650CL
Technical Expert
Posts: 8291
Joined: Thu Nov 12, 2020 1:25 pm
Car: 2013 Nissan Altima 2.5 SL
2004 Nissan Altima 2.5 S

Post

Healthy N/I alternators with internal regulation put out around 13.9~14.3V constant, regardless of load. There's no "smart charging" on an '02 QX4, so I'd say your new alternator is misbehaving.


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