Wiring 6x200W Solar Panels on Your Van Without Burning Anything

I've wired three different van solar setups now, and the 1200W range is where things get interesting because you actually have to think about your wiring topology.

First rule: never wire all 6 in pure series unless your MPPT is rated for 150V+ input AND you're confident about shade management. One shaded panel in a series string drags the entire string down to its weakest output. With 6 panels on a van roof, partial shade from trees, bridges, or roof vents is basically guaranteed.

Pure parallel sounds safe but creates a nightmare. At 66.6A Isc, you'd need 16mm² cable minimum for a short run, and good luck finding an affordable MPPT that handles 70A+ input current at 24V.

3S2P is what I'd run: three panels in series per string (72.9V VOC per string), then two strings in parallel (22.2A combined Isc). Your MPPT sees a comfortable voltage that it steps down to 14.6V for LiFePO4 charging, and current stays reasonable.

Alternative: 2S3P gives you 48.6V VOC at 33.3A. Also works, but needs thicker cable and a controller rated for higher current. The Victron 100/50 would handle the voltage but might clip on current on a perfect day.

For the MPPT controller, size it for the output side too. A 1200W array charging a 12V battery bank: 1200W / 14.6V = 82A output current. You need at least a 150/85 MPPT, or realistically two 150/45 controllers splitting the array into two 3S strings. Running two controllers is actually my preferred approach — redundancy, better shade handling, and easier wiring.

Don't forget the fusing. Each parallel string needs its own fuse (15A for panels with 11.1A Isc). Without string fuses, a fault in one string can backfeed through the other and start a fire. I use inline MC4 fuse holders — cheap and effective.