Good idea or am I dum

[richard cabesa]

OK so I have a system in an RV that is working great. 600AH of battle born batteries, 800 watts of solar on three Victron charge controllers, 2000 watt Zantrex inverter.

I am adding a Cruise N Comfort 12 volt AC and another 200 watts of solar panel.

My electrical area is pretty full and even for the 75/15 Victron which is small, I'm pressed for space.

Some thoughts,
The AC unit will be in a high cabinet with a #4 wire running 8 feet to the load side of the battery bank class T fuse.

The additional solar panel will be on the roof three feet from the #4 wire connection

If I run the #10 solar wires to the area where other CC's are its 24' round trip

Can I connect the new panel to the #4 that only runs eight feet to the battery instead of taking the longer, smaller wire route ?

Everything is on the "right " side of the shunt

 

[camelCase]

No, you need to run the output of all the panels to the input side of a charge controller.

 

[richard cabesa]

Yes, understood. But from there?

 

[400bird]

I read your post and can't fully picture the question/issue.

Can you provide a drawing of all the components? It maybe explain your concern on the #4 wire?

 

[rmaddy]

Can you put the new SCC near the A/C? Then you can run the 10AWG wires from the new panels the short distance to the new SCC. Then run the battery wires for the new SCC next to the battery wires for the A/C.

Questions:

Why are you talking about just 1 wire for the A/C? If it's a 12VDC A/C then it needs two wires - one positive and one negative.

Why do you have 3 SCCs for just 800W of panels? And why are you adding a 4th SCC for just a single panel? Seems far more complicated than needed. Are you about to have 4 different sized panels?

 

[richard cabesa]

Can you put the new SCC near the A/C? Then you can run the 10AWG wires from the new panels the short distance to the new SCC. Then run the battery wires for the new SCC next to the battery wires for the A/C.

Questions:

Why are you talking about just 1 wire for the A/C? If it's a 12VDC A/C then it needs two wires - one positive and one negative.

Why do you have 3 SCCs for just 800W of panels? And why are you adding a 4th SCC for just a single panel? Seems far more complicated than needed. Are you about to have 4 different sized panels?

The plan is to put the new SSC right inside the roof by the AC.

There would be two wire for the AC and everything else along with breakers/disconnects

I have three SCC's now because I built the system over time and each one is maxed out. Also concerns over shading as the panels were initially right up against the roof air and one panel hangs on the back so exposure varied a lot.

I'll try to attach a picture, Only has one wire for everything but should make more clear what I am thinking. Does it make any difference whether I run the long way around to the buss bars by the other SCC'c or the short way to a buss at the AC
Either way, it's connected to the battery in my mind

 

[400bird]

Ah, so the question is can I run the wire the short route? You're looking to run the new charge controller output to the power wiring for the AC.

That would work fine, your DC bus is quite a bit spread out.
Most importantly, make sure you get you the ampacity for the wire and fuse correct.
Luckily, there's no crazy math, just size for whichever is larger.

Also, you drew just one wire in the diagram, that's fine. But I just want to ensure you're running a positive and negative to each component. You are not using the vehicle chassis as you negative conductor, correct?

 

[richard cabesa]

Everything in my system is two wire. No chassis grounds.

 

[rmaddy]

I don't see an issue putting a couple of small bus bars near the A/C. Run the 4AWG wires from the battery to the little bus bars at the A/C. Then connect the A/C and the new SCC to the little bus bars.

 

[richard cabesa]

Thank you.

Now let’s throw my next dum question/theory on this.

Assume SCC output is just inches from the connection to the 4AWG wire to the battery.

Assume the SCC is producing 10A (I see this on my existing system)

The AC unit draws to 55A

now the dum question . . .

Does the #4 from the battery only see 45A of use???

not asking to skimp on wire/fuse size, just. trying to understand electricity

I are a carpenter

 

[BradCagle]

Thank you.

Now let’s throw my next dum question/theory on this.

Assume SCC output is just inches from the connection to the 4AWG wire to the battery.

Assume the SCC is producing 10A (I see this on my existing system)

The AC unit draws to 55A

now the dum question . . .

Does the #4 from the battery only see 45A of use???

not asking to skimp on wire/fuse size, just. trying to understand electricity

I are a carpenter

Yes. But for sure do not skimp on the wire because it can have the full 55a+

 

[richard cabesa]

Yes. But for sure do not skimp on the wire because it can have the full 55a+

Thank you

Wire is sized and breakered to 80A