Dual Alternator

[Laurent Kim]

Hi All,

 

I have a 2020 GMC Sierra 2500HD Denali Duramax.  I have two batteries, but how do I check for the dual alternator?  Are there two separate alternators or a single alternator with dual generator?  I see the GM parts for a dual generator and a single generator alternator.  One is much bigger than the other.

 

Thanks in advance!

Laurent

[Thankful]

Follow the fan belt behind the radiator.  It will either wind around one or two alternators.  If you have the original window sticker, it will be on it.

[Laurent Kim]

I definitely see the main one in the 1st picture, but is the one in the 2nd picture the 2nd alternator?  Would you please confirm?

Thank you so much!

Laurent

[Thankful]

Scan the build code QR sticker on the bottom of the driver door frame.  It will show you all of the three letter codes that are the options for your truck.  If your list includes the code KHF, then you have dual alternators.  After displaying the list you can then email the list to yourself to keep for future reference.

[CamGTP]

The 2nd picture is the AC Compressor on the Duramax.

 

[redwngr]

On 8/11/2022 at 10:42 PM, Laurent Kim said:

Hi All,

 

I have a 2020 GMC Sierra 2500HD Denali Duramax.  I have two batteries, but how do I check for the dual alternator?  Are there two separate alternators or a single alternator with dual generator?  I see the GM parts for a dual generator and a single generator alternator.  One is much bigger than the other.

 

Thanks in advance!

Laurent

 

Perhaps some of the misunderstanding is because all dmax 6.6's get dual batteries?

 

All duramax trucks get 2 batteries.

They are (at least on dmax) connected together to act as one big battery.

Single or dual alternators, is the same. 

 

Gasser gets the 170A as standard,

dmax gets the 220A as standard,

both can get dual alternators

 

 KW7   Alternator, 170 amps
1 -  Requires (L8T) 6.6L V8 gas engine.     

 

KW5         Alternator, 220 amps
1 -  Included with (L5P) Duramax 6.6L Turbo-Diesel V8 engine or (VYU) Snow Plow Prep/Camper Package. Free flow on (L8T) 6.6L V8 gas engine.    

 

KHF         Alternators, dual, 220-amps primary, 170-amps auxiliary
1 -  With (L8T) 6.6L V8 gas engine, (K4B) 730 cold-cranking amps/70 Amp-hr auxiliary battery is required. 

 

 

Batteries change between gas and diesel too -- the gasser gets the 730's if dual alternators package is added

(standard batteries don't get a code in the guide)

 

         Battery, heavy-duty 720 cold-cranking amps/80 Amp-hr, maintenance-free with rundown protection and retained accessory power
1 -  Included and only available with (L8T) 6.6L V8 gas engine.     
 

         Battery, heavy-duty dual 730 cold-cranking amps/70 Amp-hr, maintenance-free with rundown protection and retained accessory power
1 -  Included and only available with (L5P) Duramax 6.6L Turbo-Diesel V8 engine.     

 

K4B         Battery, auxiliary, 730 cold-cranking amps/70 Amp-hr
1 -  Requires (L8T) 6.6L V8 gas engine and either (KW5) 220-amp alternator or (KHF) dual alternators. Not available with (KW7) 170-amp alternator.

 

[Crazy Canuck]

On 8/12/2022 at 8:44 PM, Laurent Kim said:

I definitely see the main one in the 1st picture, but is the one in the 2nd picture the 2nd alternator?  Would you please confirm?

Thank you so much!

Laurent

You do not have dual alternators.  The second one would be above the power steering pump which makes checking the fluid a bit of a pain.  Had 2 on my 21 and only a single on my 22.

[Dave's Place]

ONly a single battery on 2022 6.6L diesel with dual alternators.

[Thankful]

2 minutes ago, Dave's Place said:

ONly a single battery on 2022 6.6L diesel with dual alternators.

That's interesting.  I have a 2021 6.6 diesel with dual alternators and dual batteries.

[Pryme]

On 8/12/2022 at 8:59 PM, Thankful said:

Scan the build code QR sticker on the bottom of the driver door frame.  It will show you all of the three letter codes that are the options for your truck.  If your list includes the code KHF, then you have dual alternators.  After displaying the list you can then email the list to yourself to keep for future reference.

This is cool information I will look for the QR code. So you just do that with your phone?

[Thankful]

30 minutes ago, Pryme said:

This is cool information I will look for the QR code. So you just do that with your phone?

Yes.