Van Solar in Pacific Northwest
The Pacific Northwest has some of the lowest winter sun in North America. Grey, wet months mean a panel that makes 200 Wh on a July day can make a fraction of that in December. Full-time PNW builds should roughly double their array over the annual figure and plan a DC-DC charger from the alternator for long overcast stretches. Oversize the battery for autonomy, not the panels alone.
Take a steady 1,500 Wh/day build. At Pacific Northwest's annual 3.8 peak sun hours that needs about 527 W of solar. In winter, with only 1.5 hours, the same load needs about 1334 W — that is the ×2.5 winter penalty in one number. Size your array for the season you actually travel, and let the battery cover the cloudy days.
The calculator below is prefilled with Pacific Northwest sun. Add your loads and toggle winter to see your own numbers.
Quick start with a profile:
Your daily loads
Add each device with its watts and hours per day.
No loads yet. Add your fridge to start, or pick a profile above.
Solar array
—
Add loads to size your array.
Show the math
Battery bank
—
Show the math
Charge controller (MPPT)
—
Show the math
Inverter
—
Show the math
Battery-to-inverter wire & fuse
—
Show the math
Estimated cost
—
Budget street price → premium brands.