Solar or generator for off-grid power — which one?
A generator is the cheapest system to buy and the most expensive to own. Solar is the opposite. Ten-year numbers, winter reality, and the hybrid answer.
Ten-year cost, same cabin
| Solar (1,500 W + 24 V 400 Ah LiFePO4) | Generator only (3,500 W dual-fuel) | |
|---|---|---|
| Upfront | $4,000–6,500 | $700–1,200 (unit + cords) |
| Fuel | $0 | $900–1,500/yr (2–3 h/day at ~0.4 gal/h) |
| Maintenance | $0 (wipe panels) | $200–500/yr oil, plugs, carb; 1–2 rebuilds in 10 yrs |
| Battery bank (1× replacement mid-life) | $1,500–2,200 yr 8–10 | n/a |
| 10-year total | ~$5,500–8,700 | ~$11,000–20,000 |
| Noise | Silent | 60–70 dB while running |
| Effort per day | None | Start, refuel, haul fuel |
Assumes a full-time cabin (~3,800 Wh/day), $3.50/gal gas, daily use. Part-time use cuts the generator's fuel bill proportionally — and shrinks solar's advantage with it.
Where each one fails
Solar fails in northern winters: 1.5–3 sun hours vs summer's 5–6 means the array produces a third to half of nameplate exactly when loads (lighting, longer evenings) rise. Batteries sized for one summer night can't bridge a two-week overcast. A generator fails on the bad day: fuel run out, carb gummed from sitting, or you're not home when the sump needed it. It also can't run unattended — a generator is a chore you perform, solar is infrastructure you own.
The hybrid that actually gets built
Solar sized to summer sun hours plus a battery bank (the solar size calculator and battery bank sizer do the math), then a 3,000–4,500 W generator — sized with GeneratorSizer — charged through an AC-to-battery charger for: the December recharge, well pump startup surge, power tools, and guests' surprises. The generator runs maybe 20–50 hours a year instead of 1,000, cutting its fuel and maintenance bill by 95% while covering solar's one weakness. This is the standard architecture for a reason.
When each pure option is right
Generator-only: seasonal cabins used a few weeks a year (no array to pay off), heavily shaded sites, or mobile setups where panels are a hassle. Solar-only: southern climates with 4.5+ winter sun hours, quiet-obsessed sites, anywhere fuel hauling is brutal. Hybrid: everything north of that — and every full-time homestead.
FAQ
Can solar charge batteries from a generator?
Yes — through a separate AC battery charger or a hybrid inverter's built-in charger. This is the hybrid setup's core loop: the generator charges the bank fast at 100+ A during a winter afternoon, then shuts off; the bank carries the cabin silently overnight and the next day.
What size generator complements a solar cabin?
Big enough to cover the biggest surge load (usually a well pump) plus recharge the bank — a 3,000–4,500 W class for most cabins. Anything larger is wasted hours; anything smaller can't start the pump. Run the surge math in the generator size calculator.