i dont know if its me, but i know that normally most cars have a constant 14 volts while the engine is running. As you can see below in the image, my 07 G35s constantly runs 13 volts... except on a cold start, and the meter will read 14+ volts. My friends 08 sedan is the same way, so i know its not the radar (escort x50 8500). But in my fj cruiser, it constantly runs 14v. ive upgraded my battery to an optima yellow top, and have added a small jl audio setup in the trunk. so i dont know if all those things are the issue, or is this normal? help!!

 

Hm

It should read under 13 for not running engine and when it is running(idle) should read 13.5-14.3. However you should measure it at the battery. Not sure where it is hooked up too. If you get low measurement at the alternator than you have issue with it but you have to measure it at the battery. Also voltage meter would be more accurate.

 

^+1 measure with proper volt meter at the battery and you should be within the given range, it does not have to be 14.

 

The car has a battery monitoring system. When it is low, the alternator cranks up 14.5V or so. When the battery is full, it scales down to 13.X V.

 

^ very interesting.... didnt know that the alternator could do that but is a good feature for sure

 

dats pretty cool!

without this information, I would have said a failing battery would act as another resistor in the circuit, and you loose some voltage to it.

Make sure the water level is correct in the battery