Solar & battery sizing for a fridge-only backup
The simplest case — keeping a single fridge running through outages, the most common starting point for backup power.
Open this fridge-only backup setup in the calculator →
Example daily load
| Device | Power | Use | Energy |
|---|---|---|---|
| Fridge | 120 W | 24 h/day | 2880 Wh |
| Total | 2880 Wh/day |
Sized system (LiFePO4, 12V, 1 day autonomy)
Open this setup in the calculator — then adjust for your own devices →
Notes for a fridge-only backup
These figures assume 4.5 peak sun hours and 1 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 fridge-only backup 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 a fridge-only backup need?
For the example load of 2880 Wh/day with 1 day(s) of autonomy on LiFePO4 at 12V, you need roughly 4.08 kWh of battery (340 Ah). Your actual needs depend on your devices and how many cloudy days you want to cover.
What size solar array for a fridge-only backup?
About 928 W at 4.5 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
- ENERGY STAR Product Finder — US EPA/DOE database of tested annual/typical energy use for major household appliances.
- U.S. EIA — Electricity Use in Homes — Federal reference on typical household electricity consumption by end use.
- 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.