Solar vs shore power: how much autonomy do you actually get?

I ran both setups for a year and tracked everything with a Victron SmartShunt. The data tells a clear story.

Solar works brilliantly from April through September. I was fully off-grid for weeks at a time, parking wherever I wanted. No campsite fees -- that alone saved me $30-50/week in the US, or 5-8 EUR/night in Europe.

But winter changed everything. In December in Oregon, I got 1.2 peak sun hours average. My 400W panels produced maybe 350-480Wh/day. My daily consumption didn't drop -- the fridge still runs, I still need lights, and I actually use MORE power in winter (longer nights, more screen time).

The alternator charger was the real savior. My Victron Orion-Tr Smart 12/12-30 pushes 30A while driving. Two hours of driving gives me 720Wh -- more than a full winter day of solar. If you're moving regularly, this matters more than adding extra panels.

Cost breakdown for my setup: 400W rigid panels ($350), Victron MPPT 100/30 ($180), 200Ah LiFePO4 ($650), DC-DC charger ($230), wiring and fuses ($120). Total: about $1,530. At $40/week saved on campsite fees, it paid for itself in 38 weeks.

Shore power is still king for some things. Running a 1500W space heater overnight? That's 12,000Wh -- you'd need 1,000Ah of batteries and 2kW of solar to even attempt that off-grid. An induction cooktop at 1800W for 30 minutes? 900Wh per meal. Doable from solar in summer, not in winter.

My recommendation: build for solar first, keep shore power as backup. Size your solar for 1.5x your summer daily consumption. Accept that winter means either driving more or plugging in occasionally.