My stock alternator generating 180 amps!!

[Joe Papa Sr]

Got a new (warrantied lifetime) alt, last wk, OEM 65 amp one. before install, I yanked the little rectangular blk thingy (that says on it Made in West Germany), p[laced it into the new alt, inside the alt, put the red/green wires on, and tried it out. Went to auto zone to recheck, and now theyre getting a reading of 180 amps!!!

The one they took back from me, on their same tester indicated the bad alt showed 23 amps. And, the guy confirmed to me, (I know him pretty well) that machine had been used today quite a few X and working normally.

Ever heard of this happening? I mean, 180 amps? what could be going on, elec experts?

Thanks v much for your continued advice!
Joe

[Geezer]

My concern is not that it's putting out 180 amps, though I doubt that it is, but does ithe amperage taper off as the battery get recharged to keep the battery from boiling dry.

I have seen alts put out unusally high amps associated with high voltages. The cause is most likely a lousy ground at the volt reg. The bad ground gives the reg a false reading of battery voltage and thus the reg thinks that it needs to make the alt put out higher amps than it would with true reading of battery condition

Unless you have a huge wire between the alt output & the battery I would forgo installing that alt. You could end up with smoked wiring.

[Joe Papa Sr]

Quote:

Originally Posted by Geezer My concern is not that it's putting out 180 amps, though I doubt that it is, but does ithe amperage taper off as the battery get recharged to keep the battery from boiling dry. I have seen alts put out unusally high amps associated with high voltages. The cause is most likely a lousy ground at the volt reg. The bad ground gives the reg a false reading of battery voltage and thus the reg thinks that it needs to make the alt put out higher amps than it would with true reading of battery condition Unless you have a huge wire between the alt output & the battery I would forgo installing that alt. You could end up with smoked wiring.

[Joe Papa Sr]

Sorry, guys, heres the update:

Maybe theres nothing wrong, I really dont know, as another auto zone tested it out "OK". It read about 36 amps while at 2000rpm, and battery fine. Said that even with a 65 amp rated, you should not actually see it at 65 amps while running.

Another yet store, Advance, said battery low (12.8v). Of course, Im confused as ever, and not sure who to believe (holding forehead in hand, elbow on desk)......

[Alfajay]

No, your alternator wasn't generating 180 amps.

#1, an alternator just can't put out more than its rated current. Maybe a "65 amp" alternator could go to 70, but its diodes would blow if you attempted to draw much more current than that.

#2 Power = amps X volts (right, all you EE's out there?), so 180a X 12v = 2.16kw. 2.16kw is a LOT of power - nothing on an older Alfa draws anything near that - so unless something on your car was smoking, I really doubt it. I think it was the AutoZone technician who was smoking (something).

[Joe Papa Sr]

Quote:

Originally Posted by Alfajay No, your alternator wasn't generating 180 amps. #1, an alternator just can't put out more than its rated current. Maybe a "65 amp" alternator could go to 70, but it's diodes would blow if you attempted to draw much more current than that. #2 Power = amps X volts (right, all you EE's out there?), so 180a X 12v = 2.16kw. 2.16kw is a LOT of power - nothing on an older Alfa draws anything near that - so unless something on your car was smoking, I really doubt it. I think it was the AutoZone technician who was smoking (something).