I'm working on my Transit 350 RV conversion, which has 920Ah lithium 12V batteries and a complete Victron setup with a 150/70 MPPT solar controller. I've already installed #6 copper wire to the roof, and now I'm considering getting four 250W Rich Solar panels to make the most of my available space. The panels come in both 12V and 24V versions, and I'm thinking of going with the 24V panels configured in a 2s2p setup with a 10A inline fuse for each string. This choice will result in a higher voltage of 73.8V and lower current of 13.56A, while only costing $20 more per panel. Before making my purchase, I want to ensure I'm making the correct decisions.
3 Answers
Just curious, what’s the primary use of those batteries? I assumed it might be for an EV setup, but that doesn’t seem feasible size-wise. Are you just using the RV for camping trips?
I actually use two of the Rich Solar 24V panels in a series on my setup with a 100/40 controller, and it works really well. I usually see an operating voltage in the 70s, nearing 90V when the battery is almost fully charged. If you're running cables from the panels to your controller, don't underestimate the cables; even 14AWG can handle short runs without problematic losses. This way, you can park in the shade and run cables to where the sun is.
I'd recommend going with the higher voltage 24V panels in a 2s2p configuration. Even though your MPPT might be more than necessary, it’s fine since having it over-spec can help with cooler operation and future expansion options. Just make sure to use 15A fuses for those panels to handle the higher output. Also, if you're installing them in series, try to keep the panels at the same angle; otherwise, the lower-performing panel can limit the output of the others.
Yeah, it’s a converted RV for camping now! Here’s a quick look at my setup: https://preview.redd.it/4vap2xxqs5ef1.jpeg?width=1290&format=pjpg&auto=webp&s=65338e48696161352bedbe221f696a0f6c4cf9cb