Help with 12v in 50a rv (disconnect converter )

[Jason flores]

I have a 50a rv I'm going to be running 48v (6000xp) not mounted on /in rv .I've read and watched videos to turn off converter breaker but then won't I lose my 12v system ? Lights, fans, etc

So I watched a video with ray lovele diy solar fun on youtube . He used a 48v to 12v step down could I run a seperate wire to a qs8 8mm anti spark bullet 400a 200v rated plug on my rv straight to breaker junction box ?(dotted line ) and if so would i need a inline fuse or is this not possible ? Run is about 50 ft

thanks sorry for horrible picture.

 

[TacomaJoe]

Not sure I have a complete picture here. Does the pedestal shown on your diagram have power coming from the local power company, or is it only fed from the shipping container? You don't need to turn off the RV converter unless you have an inverter in it that powers the converter.

The issue is that you don't want an inverter to draw from the battery to make 120VAC and then have a converter taking that 120VAC and making 12VDC to recharge the battery (makes a complete loop).

 

[time2roll]

If you are plugged into 120/240v power.... the converter will run the 12v system just fine.
Although maintaining a lead-acid battery in the RV could use an excessive amount of power regardless if driven by the converter or a DC-DC converter. Maybe you are removing the battery?

 

[Jason flores]

Not sure I have a complete picture here. Does the pedestal shown on your diagram have power coming from the local power company, or is it only fed from the shipping container? You don't need to turn off the RV converter unless you have an inverter in it that powers the converter.

The issue is that you don't want an inverter to draw from the battery to make 120VAC and then have a converter taking that 120VAC and making 12VDC to recharge the battery (makes a complete loop).

100% off solar no grid

 

[chrisski]

He used a 48v to 12v step down could I run a seperate wire to a qs8 8mm anti spark bullet 400a 200v rated plug on my rv straight to breaker junction box ?(dotted line ) and if so would i need a inline fuse or is this not possible ?

Because of voltage loss, may be better to run a 48 volt line to the RV and locate the 12 volt converter there. Instead of wiring it to the Breaker box, I’d recommend wiring it to where ever the 12 volt battery was.

Not all the 12 volt electronics in my RV go through the breaker box. The leveling jacks have a separate fuse box, along with one other fuse box seperate from the breaker and the leveling jacks.

You’d need two fuses. One on the 48 volt side, and one on the 12 volt side.

I don’t know your power requirements, but 50 amp leveling jacks forced me to get a 70 amp converter to power them. Without leveling jacks or slide outs, you could make do with a 20 amp or 30 amp converter. The biggest DC draw was the propane heater 12 volt fan motor around 10 amps.

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I leave my converter breaker off all the time in my RV. It can charge my 24 volt batteries at 37 amps, but that is to charge the batteries if they get low. I test it every year, but never needed to use it.

In my case the 24 volt battery pack gets charged by the inverter, but no matter how I get the 24 volts, the 24 volt to 12 volt 70 amp DC converter still powers the 12 volt side.

 

[TacomaJoe]

Unless the shipping container has 12V stuff to power, I would skip the 48-12V conversion. Run power from the container to the RV at the 120VAC level. At the RV your container power will run all the RV 120VAC stuff and the converter will make the 12V for the DC stuff and keep the RV battery charged. You don't need any inverter in the RV if you can depend on the container power.

An issue I see with pulling a separate 12V line to the RV is that you need to careful with the battery negative and the 120VAC neutral connections. Worst case is that your new 12V line negative conducts some of the neutral current.

 

[chrisski]

Run power from the container to the RV at the 120VAC level.

I think I'll check the idle draw on the inverter. The converter I use is 80% efficient, so that's not a huge factor for the amount of DC I actually use. I expect that it's 24 watts an hour or about 600 Wh a day. Depending on battery bank size, that could be a factor.

Appears the idle draw on the Victron DC to DC converter I use is less than a watt.