130 Amp alternator question: Biggest DC-DC charger for house battery?

Not to hijack OP, but can you post the model number for the controller you went with? I've been looking at Renogy for a similar setup, and couldn't find the details in your build thread. Thanks!

 

DCC30S

 

Hey All,

Sorry for the delay, lots of travel lately so I don't get a chance to check this as much.

As for alternator size to charger thoughts, we generally say rule of thumb is about half of your alt is reserved for accessories. So with your 130A alt, 65A would be reserved for accessories, radio, 12v plug ins and such. So technically our

$540 BCDC1240D REDARC 40A in-Vehicle DC to DC Charger with MPPT — Dual Input for Solar & Alternator Charging, Green Power Priority - 12 or 24V Battery Charger Suitable with AGM, Gel, Lithium LiFePO4 Batteries

BCDC1240D should be fairly safe.

As for picking a charger, it goes a bit deeper. Our general rule is you should have the ability to charge half of your house battery within 3 hours of driving give or take. If you're going to run a 100Ah battery, you can easily replenish 50Ah with our

$465 BCDC1225D REDARC 25A in-Vehicle DC to DC Charger with MPPT — Dual Input for Solar & Alternator Charging, Green Power Priority - 12 or 24V Battery Charger Suitable with AGM, Gel, Lithium LiFePO4 Batteries

BCDC1225D no problem. So no need to waste money on a larger charger unless you are hoping to future proof yourself when you jump to a larger battery.

Our BCDC line is a DC-DC charger (ALT), MPPT Regulator (Solar), and Battery Isolator all wrapped into one that can handle Lead Acid, AGM, and Lithium profiles.

 

I know in my 2017 with tow package (130A alternator) the 12v line on the trailer connector is fused at 40A, so the alternator can for sure handle that additional load on top of all the mandatory truck functions.

 

How much heat is dissipated by the BCDC2540?

I have a 100Ah Lithium-Ion, I'll drop that into a trolling battery box, but the Redarc 2540 will be bolted on the outside of the battery case.

It will ride in the truck, but portable so I can leave the fridge at camp, with a solar panel, while out running trails. Also handy at night to run my CPAP.

 

Depending on the model the 1225/1240 heat will vary but if its outside of the case it shouldn't be terrible unless you're pulling hard to charge an empty battery.

 

I've got a redarc bcdc1240 that powers a 200ah lifepo4. It's not in the truck full time but I've never had any issues.