Alternator charging while GP are on?

[Lilpooh]

I know it's been said on various 6.0 forums that the PCM won't allow the alternator to charge while the glow plugs are on.

Is this true for only the single alternator trucks? Because I have the dual alternators, and right after I start the truck, my volts will slowly climb and when I activate the high idle mod, the volts climb even faster.

Can one of you electrical guru's educate me on what's going on?

http://www.youtube.com/watch?v=BEULfjYBXPo

[Lilpooh]

Bump for the night crew!! Inquiring minds want to know. LOL!

[Lilpooh]

Bump for the early birds.

[Davey~do]

My first guess would be that when the current draw exceeds a certain threshold, (just a WAG here, say 60% of alternator output) the PCM will not allow the alternator to charge to prevent overheating/high wear issues on a single alternator. By going to dual alternators, you have effectively increased your charging capacity by 100%. Now, you've effectively cut the total current draw on your electrical system from the glow plugs by half. Since you'd now be at 30% of your total output, you would also now be below that hypothetical 60% threshold for the PCM to allow charging while the glow plugs are active.

No idea if the numbers or the theory or correct. Just hypothesizing...

[Lilpooh]

Thanks Davey-do.

Anybody else wanna play school teacher?