Wiring question

[Onemanelectricalbandman]

my camper is 50 amp and has a WBCO converter/charger mid coach(37' camper). I'm installing the Victron Multiplus 24/3000/70 in the front storage pass thru as 3, 24v 267 amp, Tesla batteries are mounted in a box on the tongue and this is the closest, best location, for the Multiplus to the batteries. Ive been informed I need a Auto Transfer Switch between Multiplus and the existing WBCO converter/charger. The WBCO converter/charger is mid coach under the refrigerator and just behind the AC/DC panel.What wire size would be suggested to run from the AC1 out of the Multiplus 22'-24' to the converter/charger and AC/DC panel. Don't want to burn this house down so thanks in advance. I'm noob but can wrench and drill.

 

[Onemanelectricalbandman]

So far it looks like 6 awg but I need Positive, Neutral, Ground so not sure what they call the wire I need.

 

[John Frum]

For mobile applications use stranded wire.
The gauge depends on amperage of the circuit and the distance.

Ancor

For over 40 years, Ancor has been the market leader in Marine Grade® wire and wire management tools. All of our products are built for the harsh marine environment and conform to industry standards.

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[John Frum]

Circuit Wizard - Blue Sea Systems

 

[Onemanelectricalbandman]

Circuit wizard is for 12,24,48v. This question is for wire from transfer switch mid coach running 25' to Victron Multiplus. It's 120v and I need Pos/Neutral/Ground and probably a circuit breaker in line?????

 

[dashdrum]

In my 30Amp rig I'm using 10-3 cable (black,white,green) for the same purpose.

https://www.amazon.com/gp/product/B07H9F1KJW/

This has the indoor/outdoor jacket which along with a plastic conduit will protect this cable running under the chassis.

 

[John Frum]

Circuit wizard is for 12,24,48v. This question is for wire from transfer switch mid coach running 25' to Victron Multiplus. It's 120v and I need Pos/Neutral/Ground and probably a circuit breaker in line?????

voltage is not that big of a factor.
The primary factors are amperage and distance.
Here is another one https://www.powerstream.com/Wire_Size.htm

 

[John Frum]

I stand corrected the effect on voltage drop is more significant that I thought.
My bad.

 

[tictag]

my camper is 50 amp and has a WBCO converter/charger mid coach(37' camper).

What is a WBCO?

Ive been informed I need a Auto Transfer Switch between Multiplus and the existing WBCO converter/charger.

I'm struggling to visualise your system but the above comment raised suspicions. The MultiPlus has an in-built automatic transfer switch that connects the inverter to the output terminals when grid/genset fails.

What wire size would be suggested to run from the AC1 out of the Multiplus 22'-24' to the converter/charger and AC/DC panel.

Cleverererer people than I have answered this, though if this cable is going to be run outside, with the possibility of being driven over, I would recommend armoured cable.

 

[Onemanelectricalbandman]

Ok. Multiplus is in front pass thru storage compartment of camper near batteries. The WBCO(brand) converter/charger that came from factory is mid-coach under refrigerator. The AC/DC panel is here as well, mounted in a panel under front face of refrigerator. Shore power comes into rear of coach(37' long) and runs to the converter/charger. Portable generator power runs in thru shore power. So I think removing the WBCO converter/charger, then wire the shore power to the AC-in of the Multiplus. Then wire from AC1 out of Multiplus into the AC/DC panel. I'm using 3 wire, 10 gauge, copper running inside the black plastic conduit along frame of trailer. But....wondering if I'll need an automatic transfer switch or if the Multiplus will automatically sense and switch from AC to DC. And it will be charging 3 Tesla batteries on front tongue of camper.

 

[tictag]

Ah, I see, a WBCO is a mains powered charger, this will be replaced by the MultiPlus. That makes sense.

But....wondering if I'll need an automatic transfer switch or if the Multiplus will automatically sense and switch from AC to DC.

Yes, it has an in-built ATS. If it senses that shore/genset power is lost it will automatically (actually the behaviour can be configured but...) switch over to inverter power (and disconnect shore/genset). You do not need an external ATS.

And it will be charging 3 Tesla batteries on front tongue of camper.

I don't know the specs of the Tesla modules but I assume that you have checked that the MultiPlus will charge them.

Other considerations:

1. It doesn't matter so much about the AC mains cables but keep the DC cables as short as possibe i.e. distance between MultiPlus and batteries as short as possible, preferably next to each other.
2. The MultiPlus has a 16A OCPD which, if tripped, will need to be reset: ensure you have access to it.

Edit: Added "Other considerations"

 

[Onemanelectricalbandman]

1) yes using 4/0 welding cable from batteries to Multiplus...approx 5-6'. Using #6 wire from mid coach junction (after removal of WBCO converter/charger) of Shore Power forward to Multiplus...approx 22'. Using 3-10 from Multiplus back to AC/DC distribution panel...approx 22'.
2) Tesla's wired in parallel...24v. They are 24v/267amp/6.4KwH batteries.
3) access to Multiplus good

Now...I started with a Zamp 230w portable panel...too small so added a 140w Zamp portable panel...too small.
SO, I added 3, 390w, 24v panels to roof. These come into a Victron 150/60 MPPT....the Zamp portable's will come into their own, separate, MPPT's to best utilize their output. (using the portables as backup if parked in shady spot, which we occasionally do). Therefore I'm trying to figure out how to wire the MPPT's and a Victron Orion....I think a 6 pole + busbar for each MPPT, The Orion 12v output, the 12v battery heater pad, the 12v electric trailer jack to hook up to, etc. And a neg busbar as well.....I assume power from all MPPT's will come onto busbar and thru Orion, converting 12v to 24v going into batteries....is this correct... I must be cross ways somewhere.

 

[Onemanelectricalbandman]

BTW...I have a BMV712 installed and battery negative will run thru the shunt. In June adding a Cerbo GX with Touch 50. All Victron components.