Better option: DC to DC or 120v charge while driving

DIY
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Setup:
Truck towing a 5th wheel camper and I plan to install a Victron MultiPlus-II 2x120 with 2 x 12V 320Ah LiFePO4 batteries. I will post my RV diagram in a separate thread since I am interested in charging while driving.

For charging, my options are

  1. Victron Orion DC to DC 50A charger and run 4-gauge wire from the truck (see diagram below).
  2. Use the 2-kilowatt Pro Power Onboard 120V on the truck to provide power to the MultiPlus

Is the 2 kW sufficient power to charge while driving or is the DC to DC charger a better option?

If I go for the Dc to DC option then this is my diagram where the full cable length is 23 feet (7 meters) from battery to charger.

DC-to-DC
DC-to-DC1812×734 83.9 KB

If I go with the 120V option then I can connect the cable to the input of the MultiPlus as I will be either on shore power or connected to the truck for power.

2

I’d go for 120v ac, no power no loss :grin:

1 Like
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Using the existing 2kw inverter wired to shore power of the multiplus would allow the multiplus to charge at ~70a vs a 50a dc-dc charger. And like mentioned less efficiency loss for any 120v loads that are powered while travelling.

Only issue with this, the multiplus input current limit would need to be set as to not overload the inverter. This also means your shore power is going to be limited at this also, which isn’t a big deal if you have say a cerbo and touchscreen to be able to easily change the limit on the fly. Otherwise it’d be quite inconvenient to be hooking the laptop up to it to change it all the time.

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Take a digital multi control panel.

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I plan to install Cerbo GX, which will help to control limits. This is really good information to prevent overloading the inverter.

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Thanks, I assume the GX touch panel work for this purpose.

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Yeah, the gx is overkill, but it’ll do the job.

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Yes like mentioned it’s a tad overkill for a basic system but it sure is nice to have once you’ve got it!

You could get away without the touchscreen and just control it through the cerbo on the app on your phone too… personally I just went with the cerbo and touchscreen right out of the gate on my first install and wouldn’t do it any other way on future setups. I was thinking it was way overkill at the time, but it’s nice to just walk by and see what everything’s doing or with a few taps be able to change input current limit or whatever you wish

There are cheaper options, but the cerbo has a lot to offer. I like the ability to monitor the system remotely and just keep an eye on things too!

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Use the on-board inverter, if you can get the Multi to work with it. Check other posts on the community about the Ford F-150 truck inverter working with the Multi.

I installed a 1200VA inverter in my F-350 and use it to charge my lithium bank through my 24/5000 inverter inside my TT. The lowest I can set the AC input current limit on my 24/5000 is 10.8A with PowerAssist enabled, which is too much for the inverter in the truck.

I use a NodeRed flow that with the push of a virtual button disables PowerAssist on the 24/5000 and sets the AC input current limit to 8A. When I reach my destination the other virtual button sets the AC input current limit to 30A and enables PowerAssist.

Since I almost never have shore power, I usually don’t bother to reenable PowerAssist.

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I was planning on installing the Cerbo, so not a problem. Thanks.

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I will search for the install that you mentioned. The truck will shut down the power if the draw is too high, so I will need to dial it back. I appreciate that recommendation.