Batteries or Alternator

[Peroni]

Ever since I got my truck its electrical system has always run at 14.1 volts - always. My volts gauge always pointed straight down and never moved once the glow plugs turned off - always.

The past several months I've noticed the voltage hunting from 13.3 to 14.3. The volts gauge also moves around a bit.

Batteries are Caterpillar 880CCA that are 19 months old. They spin the motor over fast and consistently.

Alternator is a DC Power OEM series.

I've never had the battery light come on.

All connections have been cleaned and tightened.

I'm thinking perhaps the voltage regulator may not be working right? Would this be proved by a load test? It does put out it's rated 14.8 volts.

Bad cell in a battery?

 

[Pstroke96]

un hook the batteries and check them if they are at 12.6 volts they are not the issue. any dmm will do the trick. if they are fine i would bring the alternator to the local parts house and have them check it for you

 

[PSDEng]

I've experienced the same thing. I had a new voltage regulator installed which solved the problem temporarily, but then came back again. After talking with a few folks about the next step was to swap out the rectifier in the alternator....haven't gotten to that yet.

 

[Tom S]

I think you can test the rectifer for measuring for the presence of AC voltage. Not 100% sure, I would have to do some research on it.

 

[Peroni]

Both batteries tested good.

Can't find anything amiss in the battery cables.

DC Power says voltage fluctuation is normal esp in the summer. I say BS as I've run this alternator thru 2 summers with a steady 14.1V at all times. I've been advised to keep an eye on the voltage, if it drops below 13.3 they say the regulator is failing.

 

[SPEEDDEMON31176]

Check the output at the alternator with ALL of your accessories off. If you aren't seeing 14 volts at the alternator output stud then, then you have an issue with the alternator. It sounds to me like they don't want to warranty a failing part. You also need to load test each battery individually. You can have 12 volts and 0 amps in a battery. You need to separate each battery from the other and load test them. A good battery can mask a bad one when they are tied together.