Short answer: Series adds voltage (thinner wire, needs MPPT, more affected by shade); parallel adds current (better in partial shade, thicker wire, works with PWM).
| Series | Parallel | |
|---|---|---|
| 2 × 200 W panels (Vmp 20 V, Imp 10 A) | 40 V, 10 A | 20 V, 20 A |
| Wire size | smaller | larger |
| Shade on one panel | hurts whole string | only that panel |
| Controller | MPPT | MPPT or PWM |
| Fusing | usually none for 1–2 strings | fuse each string when 3+ in parallel |
Many RVs use series-parallel (2S2P) to balance both. Always keep cold-weather open-circuit voltage below the controller's maximum PV input.
Safety: These are general estimates, not a design. Follow your equipment manufacturer's instructions and local electrical code, and consult a qualified electrician for anything connected to shore power, a house, or high-current batteries.
Series is often better for long roof-to-controller runs and MPPT efficiency; parallel is better where shade from AC units or trees is common.
Mixing is possible but costs output; match voltage for parallel and current for series.
As an Amazon Associate, RVSolarMath earns from qualifying purchases.