How many solar panels do I need for a cabin?
Panel counts by how you actually use the cabin — weekend, full-time, or homestead — with the daily watt-hour math behind each number.
Panel count by cabin type
| Cabin type | Daily use | Array size | Panels (300 W) | Battery bank | Inverter |
|---|---|---|---|---|---|
| Weekend (lights, pump, charging, internet) | ~1,450 Wh | 500 W | 2 | 24 V 100 Ah LiFePO4 | 1,000 W |
| Full-time (+ fridge, TV, fan) | ~3,800 Wh | 1,500 W | 5 | 24 V 400 Ah LiFePO4 | 2,000 W |
| Homestead (+ well pump, workshop) | ~8,000 Wh | 3,000 W | 10 | 48 V 400 Ah LiFePO4 | 4,000–5,000 W |
Assumes 4 peak sun hours and 0.75 system efficiency (wiring, controller, battery round-trip, panel heat/dust). Batteries sized for 1–2 days autonomy at 80% depth of discharge.
The math, once
Square footage doesn't matter — usage does. Sum your daily watt-hours (a fridge cycles ~1,200 Wh/day, LED lights 10 W × 5 hrs each, a water pump ~100 Wh/day for a small cabin), then: array watts = daily Wh ÷ worst-month sun hours ÷ 0.75. Panels = array watts ÷ panel watts, rounded up. Full worked examples live in our off-grid cabin solar guide.
What breaks the "2 panel" answer
A fridge roughly triples daily use — that's the line between weekend and full-time. A well pump doesn't add much daily energy (~500–1,000 Wh/day) but demands a big inverter for its 2–3× startup surge, which is why the homestead tier jumps to a 4,000+ W inverter. Electric cooking, water heating, or space heat add 4–10+ kWh/day each — keep those on propane or wood at every tier, or the panel count doubles for loads a $30 propane burner covers.
Winter changes the answer
The table uses 4 sun hours; northern winters deliver 1.5–3. A year-round cabin either doubles the array to worst-month hours (10 panels full-time) or keeps the summer array and adds a generator for December–January — most off-gridders pick the generator route since it costs a few hundred dollars instead of a few thousand. The battery bank sizer sizes the storage side once you've settled the array.
The pick
Weekends: 2×250 W panels, 30 A MPPT, 24 V 100 Ah bank, 1,000 W inverter — ~$1,200–1,800 DIY. Full-time: 5×300 W, 80 A MPPT, 24 V 400 Ah bank, 2,000 W inverter — ~$4,000–6,500. Homestead: 10×300 W ground-mounted, 48 V 400 Ah, 4,000–5,000 W inverter. Plug your own load list into the solar size calculator for exact numbers.
FAQ
Do panel counts change with 200 W vs 400 W panels?
Only the count, never the wattage: 500 W is two 250s or one 500 W module. Larger panels mean fewer roof mounts and less wiring; smaller ones fit irregular roofs and are easier to carry to remote sites.
Can I start with 2 panels and expand later?
Yes, if you buy the charge controller for the final array size upfront — controllers are cheap to oversize, annoying to replace. Batteries also expand modularly with LiFePO4. Inverters are the awkward piece: match the inverter to your biggest future load (usually a pump or tool surge), not today's.