What size wire for solar internal connections?

[Kalashnikov]

So I'm still building out my solar setup. One thing I omitted to order was all the internal wires!
- Will use the factory solar wires for connecting to the Victron controller
- NEED: Controller to switch, also output of switch
- NEED: In/out of 60A breaker (600W system)

What size to get? Should I get individual pieces with 3/8 rings? Any handy amazon links?

Thanks!

[wulfraat]

4 AWG for 600 watts to/from the controller assuming your are running those panels in parallel.

[AirMiles]

The Victron 100/30 and 100/50 controller connections are designed to fit 6 AWG. If you get 4 AWG, you will need to trim some the connection area to fit the 6 AWG connections - not a big deal. There won't be much difference using 6 or 4 awg over a couple of feet at <50A. I just used 6 AWG from the controller output, to the breaker, and on to the busbars. I used the factory prewire 10 AWG from the roof, through the switch, and into the Victron controller. Here's eight detailed pictures showing my connections between the Victron controller, switch and breaker used on both my Airstream installs using the factory prewire: https://www.airforums.com/forums/f44...ml#post2167314

Notice to connect to the busbars, I used these: https://www.lowes.com/pd/Blackburn-2...r-Lugs/4582297 because the 6 AWG would not fit into the busbar connections.

[waninae39]

#8 marine grade strand or better

AS installs #10 which is a very minimal for a single panel

#4 or better allows for lower loss and greater run lengths
google cable tables and you will see loss/ft based on wire size

[GMFL]

I install 4AWG

[AirMiles]

Minimal for one panel? Baloney! The 10 AWG solar prewire is just as capable with 600W configured in series-parallel as 600W configured in parallel on 4 AWG. I've been demonstrating this fact using 400W of panels for 250 days of use over the past two years with real-world performance on the "Solar Show & Tell" thread. https://www.airforums.com/forums/f44...ll-181608.html

For those interested, I've calculated the voltage drop for 600W of series-parallel configured panels and provided links to the calculations here: https://www.airforums.com/forums/f53...ml#post2208101

By my calculation . . . this configuration would be capable of producing 588 watts to the controller for a total loss of only 2.0%."

I've since upgraded to a 27' Airstream and will be demonstrating how 600W of panels works on the factory prewire in the Solar Show and Tell thread this summer. To date, the best day of production was 2kWh with 1/2 day of overcast skies and the maximum wattage in late November was 491W. I expect that these numbers will be dwarfed by production this summer with longer solar days, higher sun angles, and clear summer skies. So stay tuned to the "Solar Show and Tell" thread to see how 600W on the Airstream prewire works.

[Kalashnikov]

I already pulled the trigger on a bunch of 4awg cable based on wulfraats's reply. Would have bought 6awg if I had seen Airmiles' post in time.


This is for the wiring between the cluster of components related to solar inside the camper, not for the panels->controller.


Oh well. I'll trim the wires to fit.

[gator.bigfoot]

Originally Posted by Kalashnikov

I already pulled the trigger on a bunch of 4awg cable based on wulfraats's reply. Would have bought 6awg if I had seen Airmiles' post in time.


This is for the wiring between the cluster of components related to solar inside the camper, not for the panels->controller.


Oh well. I'll trim the wires to fit.

You won't regret the 4 awg. The lower the voltage drop the better. I prefer to have less than 1% in losses. Even 3% is too much IMO. On my install I needed over 50 feet of it.

Make sure you use proper connectors/crimps for it though. You don't want to increase your resistance after you through the effort of adding the better wire.

[Al and Missy]

#4 is the safer choice. Some types of #6 are not rated for 60 amps under some conditions. You want the wire to be rated at, or higher than the breaker protecting it.

Al

[wulfraat]

^^^^^^^^

#4 is the correct gauge for your application and equipment if you want to adhere to amperage ratings of the cable / equipment.

It is especially important to have the correct gauge when you a pulling some length, this is not a 2 or 3 foot run.

Welcome to the wonderful world of solar and congrats!

[Kalashnikov]

Originally Posted by wulfraat

^^^^^^^^

#4 is the correct gauge for your application and equipment if you want to adhere to amperage ratings of the cable / equipment.

It is especially important to have the correct gauge when you a pulling some length, this is not a 2 or 3 foot run.

Welcome to the wonderful world of solar and congrats!

Is it not just a couple feet? I bought 6ft of red/black each just in case. Haven't opened up my AS yet, will complete all the exterior work first as weather permits.


Expecting:

[Prewire]-10awg->[Controller]-4awg->[Switch/breaker]-4awg->[Bus Bar]