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Truck - Camper Breaker Question


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#21 ntsqd

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Posted 27 November 2022 - 08:01 PM

FWIW I used 6 ga. power and ground cables to connect the camper to the truck. 80A, 285 series breakers at each end.

https://www.amazon.c...er&i=automotive

I used 6 ga. because it was slightly bigger than Ancor Marine's calculation said was needed for a 3% voltage drop over the length of this circuit. 8 ga. would have been too small.

 

Does the DC to DC converter still need a minimum voltage drop? My understanding (& total lack of experience) was that they are more tolerant of a lower voltage then when trying to charge over the cables alone.


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Thom

Where does that road go?

#22 Vic Harder

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Posted 28 November 2022 - 12:20 AM

FWIW I used 6 ga. power and ground cables to connect the camper to the truck. 80A, 285 series breakers at each end.

https://www.amazon.c...er&i=automotive

I used 6 ga. because it was slightly bigger than Ancor Marine's calculation said was needed for a 3% voltage drop over the length of this circuit. 8 ga. would have been too small.

 

Does the DC to DC converter still need a minimum voltage drop? My understanding (& total lack of experience) was that they are more tolerant of a lower voltage then when trying to charge over the cables alone.

Thom, I can attest from personal experience, that Victron Orion DCDC converter is somewhat sensitive to voltage drop.  When I first got mine, it didn't work well at all, but a firmware update fixed it's hyper sensitivity to voltage drop.  That can be mitigated by using the optional switch to turn on the DCDC regardless of the voltage it "Senses" on the input.  It is nice not to use that, and just use the "engine running" sensor to turn on the unit.  Others here have reported that the newer units work just fine out of the box using 6 AWG.

 

This is using 2 AWG cable, 25' runs from engine bay to the breaker in the camper.  

 

I also find that the Victron unit runs VERY hot, and needs a fan or very open mounting to keep it cool while running.  I imagine that having more voltage drop on the input would make the unit draw even more current in order to generate the 30A output it is capable of.  That makes for even more heat.  


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