Alternator question

[Tippin Spotted Cow]

Alright, quick one here. If the truck is off... as far as the ignition switch goes... but the motor is still running, does the alternator still charge the battery, or does the truck need to be on to work the regulator?

 

[jdooner]

Seems to me this could be checked by measuring your voltage at the battery posts, if the voltage is 12 volts it's not charging, over 13 volts it is charging. Someone correct me if I'm wrong.

 

[HBarlow]

Huhh? How could the ignition switch be turned to the OFF position and the engine still be running?

Jdooner's reply is correct. You can detemine the answer by measuring voltage across the battery terminals. My guess is if the engine is running the alternator is charging.

 

[Midnite]

A lot of times when the VE pump starts to fail, the shutoff solenoid will fail to kill the engine, so it'll keep running after you turn off the key.

Mike

 

[PToombs]

And some people remove the guts and install a pull cable on the shut off.



Sorry Matt, I'm not sure on this. What the others have said about testing it is the easy way, IMHO.

 

[cerberusiam]

Off hand, I'd say charging would be impacted with the key in the off position. I think the PCM needs to be energized to function correctly. Just a guess though.

 

[boatpuller]

Alternator won't charge without an exciter voltage, which is provided from the ECM or the voltage regulator when the key is on. So no it won't charge with the key off.

 

[Jgolden]

Don't some alternators "self excite" above a certain RPM?

 

[JLEONARD]

I do not believe it will charge.

Don't some alternators "self excite" above a certain RPM

I'm not going to even attempt to comment on this. :-laf:-laf

 

[cerberusiam]

Don't some alternators "self excite" above a certain RPM?

That a Pete question??







:-laf:-laf

 

[Jgolden]

Bosch alternator on my Saab self excited at 2000 RPM. As to Pete I'm sure he'll have to comment. He is a fine upstanding..... losing the signal here... ... ...

 

[Tippin Spotted Cow]

I didn't think it would charge, but it's just helpful to know. Sometimes, with the kind of company I keep, my headlights end up being worklights, and I guess it'd be good to know if I should leave the key in for this kind of thing. I guess if the motor is running with the truck off, and the battery dies, who cares? Put the key in and charge the thing back up. Not the best for your battery, but at least you're not stranded...



The main reason I brought this up yesterday, though, is that I killed my battery, and had to get a jump, so when I got home I was going to take the key out and lock the truck with the motor running to charge the battery for a bit, but I guess this answers that question.

 

[PToombs]

ummmmmm, self excited, ummmmmmm. I gotta go, see ya! :-laf