Enter your essential backup load and hours of autonomy — see the right LiFePO4 capacity in kWh, how long it runs per charge, and a recommended model. Add your PV array to check solar recharge during multi-day outages. No email required to use it.
Usable kWh = load (kW) x hours x days. Nameplate = usable ÷ depth of discharge. Daily solar recharge = array kW x sun hours, derated ~10%. Figures are indicative; a tailored quote confirms exact sizing and inverter compatibility.
| Metric | Value |
|---|---|
| Required usable energy | — |
| Required nameplate (to buy) | — |
| Runtime per full charge | — |
| Daily solar recharge | — |
Want this configured for your loads with distributor or OEM pricing? Leave your email — we reply within 24h, no obligation.
This calculator sizes the bank from your loads. For the full picture — how a PV + storage system keeps the lights on during an outage, battery vs generator, and which NovaBESS options fit your home — read the solar battery backup guide. Or compare a branded turnkey unit in our Tesla Powerwall alternative comparison.
Add up the watts of the loads you want to keep on during an outage, multiply by the hours of autonomy you need, then divide by depth of discharge. A 1,000 W load for 8 hours needs 8 kWh usable; at 90% DoD that is about 8.9 kWh nameplate. Use the calculator above to turn this into a real model.
Divide usable kWh by your backed-up load in kW. A 10 kWh battery at 90% DoD gives ~9 kWh usable; running a 1,000 W (1 kW) essential load, that is about 9 hours per charge. Running a 3 kW load, it is about 3 hours. More load = fewer hours.
Yes, if you have rooftop PV. Sunlight recharges the bank each clear day, so a correctly sized system can ride out an open-ended outage — not just one charge. Enter your array size in the calculator to see daily recharge vs your daily draw.
Yes. LiFePO4 supports 80–100% depth of discharge (so a 10 kWh nameplate delivers close to 10 kWh usable) and lasts 5,000+ cycles, far more than lead-acid's ~500 cycles. That means a smaller, longer-lived bank for the same backup runtime.
No. A battery backup also works charged from the grid (see our home battery backup without solar guide). But pairing it with rooftop PV lets it recharge for free during extended outages — the strongest setup for blackout-prone areas.
Tell us your essential loads, country and inverter — we'll configure a HomeWall or HomeStack system and quote distributor or OEM pricing.
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