LOL...Troverman....why in the heck would "Dual HD alternators" give me one heavy duty...and one standard one. Shouldn't DUAL HD alternators mean you are getting TWO Heavy Duty Alternators..??? I've seen stranger things.....

 

I would hope they would be the same thing. Like the idiots who design different size windshield wipers. Come-on, geeez. Have some pity on the owners.....I need an alternator. Uhh the one on the left....the vin # above or below what?.....The mounting hole is on the left.....No the connector doesn't match.....Like Chevy with starters for the 350: 3 bolt, 4 bolt flange to the left, flange to the right, solenoid on board, no solenoid but special contacts, oh you wanted the two bolt one. We don't have any but try Pontiac (RIP) down the street. They might have one which will match.

 

Well, based upon the order guide, here is what I come up with: the extra heavy duty alternator on the 6.7L is 220A. The standard alternator is 157A. Added together is the 377A which is your rated output. Make sense now?

 

I am curious if there will ever be a draw of 377 amps. Even fully discharged batteries do not take full amperage from the alternator. I know my camper can only draw 30 amps on its charging circuit limited by the truck distribution/fuse panel. Not much when the batteries are low after a week of cloudy weather off grid.

 

I think if you had all your 6 upfitters hooked up and operating at max capacity, you had a trailer using full capacity, the truck had just started and was using supplemental heat, headlights all on, front and rear heated seats on, operating a plow or winch, etc...you might use most of it.

The important point to remember is that an alternator can only generate that amperage during ideal temperature and RPM conditions. So during very hot conditions and idling, 377A might be half of that.

 

It will be interesting to see if the glow plugs still dim the headlights. The headlights on the '01 with a 110 amp come up after about 4 minutes when the glow plugs shut down.

 

The headlights are not dim during glow plug operation on my 2016. In cold weather, not only are the GPs running but also the urea tank and lines are being heated, along with heated seats, supplemental heat, heated rear window, heated mirrors, headlamps, fog lamps, trailer lights / batt / brakes, and audio system.

 

Lot of electric being used. Even more options now with cameras and computers although the resistance heat and incandescent lighting are the big draws. Imagine a Chevy Volt with that much draw? Wouldn't make it to the corner.

 

I like the idea of having a redundant alternator for reliability.

BTW, the higher output alternator doesn't hurt fuel mileage. The load the alternator puts on the engine is directly related to its current output at any given time, not it's rated output.

 

If you read the Build and Price Alternator section it reads:
"Dual Heavy Duty Alternator" No "s" on the end. I asked chat about it and she will get back within 5 days. Standard on 6.7 SD is now dual alternators.

 

Good catch Rasalas....I bet that's it...I just looked in the guide also and it does not have an "s" on the end....So I believe Troverman is correct with the combination of output with one regular and one heavy duty to give you the "Dual Extra Heavy Duty Alternator" option.... 67B in the guide.

 

There is a small amount of extra drag generated by spinning the alternator fan, shaft, and windings. Pretty negligible especially on a diesel. However, both alternators will be generating "some" power at all times, even if they are sharing the load.

I like the dual alternators too.

 

I couldn't tell if the supplement heats works or not on my truck.

 

I can on mine. It blows warmish air within 30 seconds of starting in the winter. It never bows hot like the heat does as there is just too much air volume passing too quickly past the heating element. But, it's better than nothing...