OffGridCalcs

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Size your independent power system

Every calculator here answers one real sizing question (panels, batteries, inverters, charging) and shows the working: the formula, the assumptions and the mistakes that undersize systems.

Formulas shown, every tool
Runs in your browser, no tracking
Written by a former ship captain
MPPT controller inverter sunarray chargestore converthomeEV

Solar · the sizing chain

01Solar panel sizeHow many watts of solar you need for your daily energy use and sun hours 02Battery bankAmp-hours needed for your loads, autonomy days and battery chemistry 03Inverter sizeContinuous and surge watts your AC loads demand
04Solar wire gaugeComing this week

Batteries & charging

05Battery charge timeComing soon
06Charge controller sizeComing soon

EV & vehicles

07EV charging timeComing soon
08$EV charging costComing soon

Backup power

09Generator sizeComing soon
10Appliance power drawComing soon