Dual alternator usage

[Mark M]

I am getting a 3500 with dual 220A alternators.

I want to charge lithium batteries in the truck bed. I’d like to draw as much power as possible.

In my current truck I only pull 30A to charge a smaller battery pack. The cables are wired from the chassis battery back to the house batteries.

Can I do that with the factory dual-alternator setup? I guess I’m asking how much continuous current I can safely pull through the factory wiring and also how much continuous current can I safely pull from the dual alternators.

Is there a better way to do this?

I’ve got the alternator power curves but that shows maximum power vs alternator RPM. How much can I use for this one giant accessory.

 

[Brutal_HO]

The HAPP is rated to 300A.

Chassis ground is only good to 50A.

Entire thread is a good read but HAPP info is in post #7.

In Cab Power FAQ -- AUX Switch power info -- Chassis power info

This is a roll-up thread that should answer most if not all questions regarding power availability in the cab. A lot of the credit for technical detail goes to @Jimmy07 without whose help and guidance much of this info would be hard to assemble. There are other contributors, you know who you...

hdrams.com

 

[AH64ID]

With the factory 7 pin wiring you can use a 18A DC-DC converter.

As mentioned the HAPP is good for 300A. Large negative loads are supposed to be grounded to the block.

How big of a DC-DC charger are you planning?

 

[Mark M]

With the factory 7 pin wiring you can use a 18A DC-DC converter.

As mentioned the HAPP is good for 300A. Large negative loads are supposed to be grounded to the block.

How big of a DC-DC charger are you planning?

120 Amp

 

[AH64ID]

120 Amp

No issues with that load.

I would take power from the HAPP, run it thru a fuse, and back to the DC-DC charger. I’d also use an aux switch, if you have them, for the remote on/off of the charger.

 

[Mark M]

As mentioned the HAPP is good for 300A. Large negative loads are supposed to be grounded to the block.

By block you mean engine block?

 

[AH64ID]

By block you mean engine block?

Yes.

 

[Mark M]

Yes.

Is there a recommended location on the block?

 

[AH64ID]

Is there a recommended location on the block?

I used one of the bolts on the front of the head that supports the radiator hose.