diy solar

diy solar

Starting to plan my build...

JeromeS13

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Joined
Jun 13, 2022
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Good afternoon, everyone.

I'm in the very beginning stages of planning my build. I have a 2019 Fleetwood Discovery Class A motorhome, which is pre-wired for solar (10 AWG from the roof). I have already purchased 2x SOK 206AH 12V batteries, but I plan to purchase two more eventually. I plan to have 1200-1600 watts of solar and will be using all Victron components and probably Rich Solar panels. What I'm trying to decide is:

1. 12V or 24V
2. Do I use the existing 10 AWG with half of the panels and a single, charge controller (and run another 10 AWG for the other half, another parallel controller)? Or, do I just run larger 6 AWG to feed a single, larger controller?

Thank you!
 
1)

12V:
1200W/14.4V = 83A
1600W/14.4V = 111A
Will likely need 2 40-50A controllers or a single 100A+ controller

24V:
1200W: 41.5A
1600W; 55.5A
Single 50-60A controller will suffice.

2)

10awg can handle 30A

1200W/30A = 40V, i.e., if you have an operating PV Vmp > 40V, you should not exceed 30A.
1600W/30A = 53V, i.e., if you have an operating PV Vmp > 53V, you should not exceed 30A.

2S 60 cell panels will be Vmp = 60V
2S 72 cell panels will be Vmp = 80V

If you configure your array correctly, you should have no issues using the 10 awg.
 
Last edited:
I went with dual controllers (Victron 100/50) vs. one big one.

If the 24V multiplus II was around when I started my build, I would have gone with that.

This is my all Victron 1200W solar setup on my 5er.

DC wiring 290RL rev 1.jpg
 
With a class A - you need to either sever the connections between the house and chassis batteries and/or give very careful considerations to those connections.

In my case, I removed the battery charge isolator.

I now have enough solar 1220w that I seldom need help from the alternator. I did add a Victron Dc-Dc non-isolated 30a charger to help charge the batteries when the alternator is running in case of bad weather when driving.

My rig also has a charger to keep the chassis battery charged from the house battery. Designing a system to keep both batteries charged and healthy takes a bit of thought.

Good luck
 
You guys are awesome. I appreciate the quick and thorough responses!

Rocketman, yes, I've already noticed that. I installed an Li-BM225 in place of the OEM isolator. The only limitation now is that the chassis batteries no longer charge when connected to shore power... Having the 12V chassis requirement definitely adds to the complexity...
 
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