89 replies to this topic

[Wallowa]

My alternator puts out 105 amps at 750 rpm and 170 amps at 2250 rpm. I ran 6 gauge welding cable from the truck battery to the charger and the charger to the camper battery, and used 60 amp circuit breakers like Victron recommends. I think the Victron Smart 12/12/30 DC-DC charger will be OK with this set up. We'll see!

 

 

Having the Victron Smart 12/12/30 DC-DC installed in '05 Tundra....4 gauge wire..w/ 80 amp marine breaker..

Edited by Wallowa, 24 May 2021 - 12:13 AM.

[JimBow]

Having the Victron Smart 12/12/30 DC-DC installed in '05 Tundra....4 gauge wire..w/ 80 amp marine breaker..

 

Cool. I think that charger will be especially nice in the winter when there isn't a lot of sun. 

 

One thing though. 6 gauge wire is the largest size that the Victron charger will accept. The 4 gauge would have to be stepped down somehow. 

[Vic Harder]

I would hope that the 4g wire has a breaker at each end.  The wire size can be stepped down there.

[Wallowa]

I would hope that the 4g wire has a breaker at each end.  The wire size can be stepped down there.

 

From 4 t0 6 gauge...I will leave that to KP....why breaker at each end?

[rando]

From 4 t0 6 gauge...I will leave that to KP....why breaker at each end?

 

In general because either battery (truck or camper) can provide current to the wire, so in the event of a short you want to be able to interrupt the circuit at both ends.    If you have a DC-DC converter in the camper you don't technically need the breaker at the camper end (as current won't flow backwards through the DC-DC) but it is still probably wise to have as a way to disconnect the DC-DC in the camper as opposed to under the hood of the truck. 

[JimBow]

I put the breaker in the engine bay by the battery. You should only need one breaker for each continuous length of wire. You'd have to put the breaker in the camper by the charger in order to step down 4 to 6 gauge. That should work fine. 

[rando]

I put the breaker in the engine bay by the battery. You should only need one breaker for each continuous length of wire. You'd have to put the breaker in the camper by the charger in order to step down 4 to 6 gauge. That should work fine. 

 

If you are only using one breaker it must be in the engine bay next to the battery, otherwise the run of heavy gauge wire the length of the truck is unprotected.   If you want to add a second breaker it can be in the camper near the DC-DC converter. 

[JimBow]

If you are only using one breaker it must be in the engine bay next to the battery, otherwise the run of heavy gauge wire the length of the truck is unprotected.   If you want to add a second breaker it can be in the camper near the DC-DC converter. 

Yep. You need 2 breakers then. Thanks for the explanation, Rando. 

[Wallowa]

Thanks...I am not doing the install...but knowing this is very beneficial...I prefer to understand what works and what doesn't and the why.. appreciate the information...

[ri-f]

Seems to me that if you are going to run 4 AWG from the engine battery to the DC-DC charger, and need to step it down to 6 AWG to fit your DC-DC charger, then you could use a Blue Seas Power Bar Bus as your step down connector, just before the DC-DC charger since you will already have a circuit breaker at the engine battery end. You don't need a second circuit breaker before the DC-DC charger. The second circuit breaker for the camper battery should be after the DC-DC charger and just before the camper battery. And that short wire run could simply be 6 AWG. At least that's how I run mine and it works as it should. I'm using a Sterling DC-DC in my setup (not a Victron). I may be wrong but I doubt it's any different with your setup.