Dc-to-dc wiring

[2019 Cummins]

Going to be adding a dc-to-dc charger in my 5th wheel. Running either 2 gauge or might go 1/0. Question is instead of running a red and black continuous from the engine compartment to the back of the truck with a Anderson connector. Has anyone had any good or bad experiences running the negative from the battery to the chassis and the back of the truck chassis to the negative side of the Anderson connector?

 

[Andrewr05]

It's not really recommended beyond like 50W, especially at a distance of your whole vehicle length plus tailer/RV wiring.

It works on the vehicle itself (or on something say like a travel trailer/toy hauler because you are likely only running the taillights and marker light plus maybe a few low wattage interior lights) because most things are low draw and/or only have to travel the distance of the chassis.

You will save yourself a lot of headaches down the road if you just run a dedicated and properly rated negative and positive wire.

 

[2019 Cummins]

It's not really recommended beyond like 50W, especially at a distance of your whole vehicle length plus tailer/RV wiring.

It works on the vehicle itself (or on something say like a travel trailer/toy hauler because you are likely only running the taillights and marker light plus maybe a few low wattage interior lights) because most things are low draw and/or only have to travel the distance of the chassis.

You will save yourself a lot of headaches down the road if you just run a dedicated and properly rated negative and positive wire.

Gotcha thanks for the reply. I am planning on running 1/0 to the back of the truck red and black. 40 amp dc-to-dc charger. I was just curious if there was anyone that's use the chassis as a ground.

 

[theoldwizard1]

Sorry for the late post.

If your DC-DC charger is capable of outputting 40A at up to 15V (rounding up) that is 600 watts. If it is 80% efficient (low estimate) it needs aboyt 750 watts of input power. Most modern vehicle reduce the charging voltage suppled to the vehicle battery down to about 13.2V after 5-10 minutes of run time. That would mean your DC-DC charger COULD draw up up about 60A !

Forget volage drop from the cables running from the vehicle to your trailer ! Most modern vehicle do not have an "extra" 60A capacity, especially if you are running the A/C and headlights and taillights.

I would drop down to a 20A DC-DC charger. 10 gauge wire would then be adequate, especially since the DC-DC charger will "boost" it up to the correct voltage to charge your batteries. Yes, your batteries might not be fully charged when you get to you destination !