gringopapo

Hi All,

I've got a 2015 Express 3500 van. I'm thinking of either installing a DC-DC battery charger or an inverter to charge a 200ah battery inside the vehicle. The portable power station I'm going to build is similar to this: https://www.bluetti.com/products/blu...-power-station but I'll be buying the components individually.

Question is, I have the 145 amp alternator (RPO code KG3) and I'm not quite sure how many amps I have available for me to use. Ideally something like 30amps would be my minimum requirement but it would be nice to pull maybe 50 amps.

The only data points I've been able to find on the internet is this guy named Forest that was trying to pull 60amps from his stock alternator (not clear to me which stock alternator he had). He couldn't pull that many amps until he put a high output alternator in ( ).

Any idea out there how many amps I can safely pull with a 145 amp alternator?

Triaged

The small option for the van is 105A so 40A max. That isn't at idle though. You are going to need a high idle switch.

mountainmanjoe

30A at idle is all you can hope for, no matter what alternator you use. That number is deliberately engineered. If you make the alternator work any harder than that you'll stall the engine or make it run poorly. If that is not enough power for you, I would recommend a generator.

phantomjock

Greetings - New here on the forum. I own a 2008 Chevy Express 2500.
It is a Camper Van (Roadtrek170), so upgrading the alternator was an important task. [the generator was shot - so removed]

I purchased and installed a 420Amp alternator. It works like a champ and provide 140+A at idle. I can charge my start battery and house battery bank with ease. Just my experience.
It was a simple remove and replace (I did remove the fan to work the serpentine belt easier).
I specifically went with a larger capacity than needed to get the reserve amps, and handle the engine bay heat.

Cheers - Jim

mountainmanjoe

I doubt it, but even if it was true, you definitely don't want your alternator eating 2.5hp at idle
A DC-DC battery charge controller is the ideal solution

phantomjock

Yes and I have installed a 200A DC2DC charge controller. Pricey, but it is balanced with the alternator. All designed to have a non-generator solution.
And you are very correct - nothing is for free (HP consumed for charge), the load on the 6.0L is actually higher with a High Idle mod engaged to ramp up the output - and the HP consumed!
But - I do get quite quick recharge times on the lithium bank.

Cheers - Jim