Alternator voltage

I was just about to ask similar question.

Mine shows 13.5 or 13.6.

Is that about right?

 

if everything is working right. it should show above 14.v. with all lights and what not. 13.1 will still do the job. provided the lights are off.

the truck might run till it dies though without any codes. seen that happen on a pete dump truck. 10.5 volts before the computer shut down.

 

Yes clean everything, and test batteries while you have cables off.

Also if this is a sumwhat newer truck Volvo has a recall for the battery disconnect junction which shorts out, kind of acting like a dead battery while running... till it melts down!

 

it is normal
over 13 and lower 14.8 is norma

 

Air temperature also has an effect, tho the primary determining factor will be the batteries "needs", depending on their state of charge.

Also be aware, as a rule, your charging voltage will show lower as the air temperature increases.
Hot weather = you may run at 13.0 v to 13.5 v, whereas in colder/frigid weather the alternator will put out higher voltage (13.5 v to 14.5 v) to compensate for additional battery drain (their state of charge will be lower the colder the batteries are).

Anything lower than 13.0 v ... tends to indicate a problem.

 

check your output at the alternator also.

just left phoenix (105) and my alternator reading was the same as montana 2 months ago. (35)

 

Between 13 and 14.3 is normal.
All the current alternators have the regulators built in. The regulators measure the the battery voltage and tell the alternator how much to put out.
Colder weather batteries tend to read lower so the regulator runs higher.
Sometimes as alternator/ built in regulators tend to put out lower as they age but doesn't mean they are going out.
Turn everything on and see if it's maintain above 12. 8 and your good to go.
Invertors tend to make alternators put out higher by confusing the alternator thinking the batteries are low or large batteries consumption.
Also volt meters tend to vary greatly.