Dumb question - can Advanced Auto/AutoZone test my alts?

[AJMBLAZER]

Big Ugly is still 24v start and the alts are stock standard military issue.

Was just wondering if I had to have the alternators tested could I just drive it down to Advanced or AutoZone and have them test the alternators with their rolling alternator/battery tester?
Each alternator is only 12v correct? It's just how they are hooked into the system that makes the 24v...or am I screwing up how it works again?

 

[FMJ]

My understanding is that they are 12 volt with seperate grounds, suppling 12 volts to each batt......

 

[m16ty]

Can they? Yes.

Can you find somebody with enough brains that works there to test it? Probally not.

When I go to Auto Zone if they can't look it up in the computer they are lost. There are shops around that Alt. and startes are their main business. They should know what to do.

 

[DriverSideImpact1008]

Yeah I agree with m16ty. I've had similar experience with Auto Zone. Napa might be able to and they usually have fairly knowledgeable employees. Otherwise check the yellow pages for a Charging/Starting specialists.

 

[AJMBLAZER]

I'm not asking about your guys, I'm asking if the machine they have can test it. The guys here at Advanced always know what they're doing (and one has two lifted Chevy's and another has a Monte Carlo muscle car) and have never done me wrong testing my alts and batts.

I want to know if the cart they pull outside to my vehicle can test these alternators while they are sitting on the truck with it running.

 

[DriverSideImpact1008]

If they know their stuff, take it in and ask.

 

[randyscycle]

Can you find somebody with enough brains that works there to test it? Probally not.

I think I'd find a competent electrical shop to handle it. The complexities of a 24 volt system with more than one alternator may lead to a few burnt diodes, or worse yet a destroyed alternator if the tester is incorrectly used. They would somehow need to isolate each alternator to see what they are doing independently. I don't know if the testers they use are capable of 24V input anyway. Most likely since all they do is passenger car stuff, they won't work on an MV application. The testers they use for the on-car thing in the lot, are just a voltmeter and diode tester that looks for AC voltage in the system when operating. There is a load tester incorporated as well, but you shouldn't load a running alternator.

Just grab a multi-meter and check the output yourself. If the output voltage is good, then switch it over to AC and see if there is any AC voltage present. That will tell you if there is a diode issue.

 

[AJMBLAZER]

Okay, so sounds like their stuff isn't up to the complexities of this system.

 

[beaubeau]

WOW Sounds complicated. All U gotta do is hook up tester to Bat terminal on Alt. Pos to batt., Neg to Isolated grd. Start vehicle and see what U have for voltage. I believe u can test at Bat for voltage. Just test front batt. for 12=14 volts with engine running and test rear batt. for 24-26 volts. I like the check batts. for voltage before and after running. I have just converted mine to 12 volts and all is less complicated. I am no Electrical wizzard, I could be wrong, but thats the way I have tested in the past. Be sure to adjust tester 12 volts and 24 volts. Phil

 

[CCATLETT1984]

AJM, yes the machine can test it, they must hook up the negative lead to the ground lug on the alternator.

 

[AJMBLAZER]

Ah, at last, a clear answer!

Cool. No problems now but if I ever get curious I guess I know I can have them tested without too much trouble.