I traveled to Ohio last week and I noticed that when I started the Cummins in morning 25degree, the heater defrost blower speed varied while the volt meter varied too. The volt meter stayed within the white arc of chargind, but it varied along with the blower speed. Is there something pulling power during the idle warm up that pulls that much electric during warm up? Everything went back to normal after a few minutes.

Thanks,

Happy New Year....

 

All normal,, it is ur grid heater cycleing,,untill it reachs temp

 

jmn1960
Thanks, the volt swing was the full range of the white arc. I was thinking something else was causing excessive drain.

 

Nope, he's right. Grid heaters. They suck a lot of juice.

 

yep grid heaters... there are 2 grid heater elements sucking down a combined total of 190A 2280watts 95A draw for each element. and there are two stages...initial startup stage pulls from both elements, then as the truck starts warming up it will only pull from 1 element reducing the draw to just 95A which doesn't pull so hard on the alternator.


you see your lights dim and voltage drop to 12v because you have a 135A alternator factory and grid heaters are drawing 190A. its the reason you have two batteries in your truck...it does not take two batteries to turn the starter and keep the computer online... it does takes two batteries to turn the starter while those grid heaters are running though...

 

My 93 d350 only came with one battery ,, even from the factory,,

 

your 93 also does not have 2 computers and an injection pump circuit board to run during grid heater cycles

 

My 98 doesn't either. But it's got 2 batteries.

 

Not sure but I think the 136 alt was a option. I know standard they come with 117 amp alts. If it did come that way then that would cause way more of a drop in voltage. I barely notice mine and my lights would hardly dim at all and I have the 136 amp

 

if you don't want the voltage to drop at all you can always go to the 220A ambulance alternator

or mean green or another aftermarket badged ambulance alternator.

they were a factory option for cummins based ambulances that needed the extra juice to run their medical equipment. grid heaters will not be able to overpower the 220A alternator.