Can the stock 130a alternator and v8 handle a 50a load?

[JGAN]

I want to install a DC to DC charger for to charge my house battery while driving. ai was wondering if a 40a-50a DC to DC charger will be safe for the V8 electrical system?

[cojo]

Based on the Body Builder Guide for the NV, there is extra capacity available for upfitter use to power auxiliary equipment. There are multiple power circuits available, two of which are rated at 50A max load. I have a Sterling 60A B to B charger installed in my 2500 V8 that has been working fine for 2 years with no issues. You will be fine with your 40-50A charger.

[radin2son]

The stock alternator in our 2012 SMB camper van charges the 2 house batteries to 85%+ capacity while driving or idling. (Shore power is needed to get to 100%.)  This still is the case, at least for SMB builds. 

[WanderlustAV]

Does anybody know how much the van draws off the alternator?  i.e., max amps if you got the ac/heat, etc. all running 

 

I need to replace my Sure Power 1315-200 with a DC to DC charger since I upgraded to lithiums and was trying to sort out the right drop in replacement.    @JGAN what did you end up with in your setup?  Also V8 here. 

[crusty]

The stock alternator powers a 400 watt inverter.  Once you factor in it isn't 100% efficient, that is about a 40A load.  I take that as there is at least 40A of capacity.  And that is available while running the A/C, with the radio, wipers, lights, and defrost all running as well. 

 

I had an old truck that I put EFI on to replace the carbutator.  Once I did that I had charging issues at idle at night with the lights on and the A/C running.  Was OK while driving, just idle.  Pulled the numbers and it was only a 40A alternator.  Which 40A at speed was actually enough.  It was just at idle it was a little short.  That was a 70s low tech alternator.  This modern stuff is really good at idle output. 

[Local Apparent Friday]

250a alternators are readily available for these as well, for anyone that wants/needs the power.

[JGAN]

@WanderlustAV I went with the renogy 40a DC-to-DC converter which pulls ~50a and have not had any issues.

[WanderlustAV]

Thanks y'all! 

 

50-60a of charging sounds like a sweet spot for the stock alternator.  

 

I don't think I really need a dc to dc charger but the isolator that's currently in there pulls some juice in order to stay open and thinks it's feeding FLA house batts so that's gotta go.

 

I am way into large/dual alternator charging of lifepo4 batteries.  Not going to get into that with Roadtrek's existing wiring but I'd be all over an upsized alternator if this was my own build.  

 

 

[WanderlustAV]

So, a year later here, I finally installed a Wagan Tech 40 amp dc to dc charger.  I wanted to just stick something in the engine bay near where the old battery isolator was and it was basically this or a Redarc.   

 

Wagan indicates: "If your vehicle has fixed voltage or temperature compensating alternator (standard alternators) installed, leave the Ignition Override cable (BLUE color) open. If your vehicle has smart (variable voltage) alternator installed, the Ignition Override cable must be connected to the vehicle’s ignition. The 40A DC to DC Battery Charger will only operate when the vehicle’s ignition is turned on."

 

Turns out the NV has a smart alternator, or that's what I'm reading in the attached from the FSM- "Adjustment range of power generation variable
voltage control" -so I suppose I'll connect that blue wire.  

 

Anyone else have to connect to ignition for their dc-to-dc charger and know a convenient spot to hook in?

[JGAN]

@WanderlustAV sorry for the late reply, but if you haven't figured this out, I don't believe it's a smart alternator. It just runs off the belt when the engine is running. I just powered it off of the oil pressure switch, which only gets 12v when the engine is running. The wire is in the fuse box in the service manual.