Solar & battery sizing for an off-grid cabin
A weekend or full-time cabin running lights, a fridge, charging and a water pump on solar with a few days of cloudy-weather backup.
Open this off-grid cabin setup in the calculator →
Example daily load
| Device | Power | Use | Energy |
|---|---|---|---|
| Fridge | 60 W | 24 h/day | 1440 Wh |
| LED lights | 40 W | 6 h/day | 240 Wh |
| Water pump | 600 W | 0.5 h/day | 300 Wh |
| Laptop | 50 W | 4 h/day | 200 Wh |
| Wi-Fi router | 12 W | 24 h/day | 288 Wh |
| Total | 2468 Wh/day |
Sized system (LiFePO4, 24V, 3 days autonomy)
Open this setup in the calculator — then adjust for your own devices →
Notes for an off-grid cabin
These figures assume 4.0 peak sun hours and 3 day(s) of autonomy. If your location is cloudier, your usage is higher, or you want more buffer, increase autonomy or array size. The button above opens the full calculator pre-loaded with this off-grid cabin setup, so you can change any device, voltage or chemistry and see the system resize instantly — the example is a starting point, not a prescription.
Frequently asked questions
How many batteries does an off-grid cabin need?
For the example load of 2468 Wh/day with 3 day(s) of autonomy on LiFePO4 at 24V, you need roughly 10.48 kWh of battery (437 Ah). Your actual needs depend on your devices and how many cloudy days you want to cover.
What size solar array for an off-grid cabin?
About 894 W at 4.0 peak sun hours, to recharge the daily load. Cloudier locations or higher usage need more.
Looking for a definition or a quick answer? See the solar & battery glossary for terms used on this page, or the FAQ for common sizing questions.
Sources & standards
- NFPA 70 — National Electrical Code (NEC), Articles 690 & 705 — Governs PV source/output circuits (Art. 690) and interconnected power production sources (Art. 705) in the US.
- IEEE 1013 — Recommended Practice for Sizing Lead-Acid Batteries for Stand-Alone Photovoltaic Systems — Widely used engineering practice for days-of-autonomy and depth-of-discharge sizing methods, referenced here for the general sizing approach.