Add each 12-volt load with its current draw and how many hours a day it runs. Then set how many days of reserve you want before recharging.

Days between recharges from shore, solar, or alternator.
Drives usable depth of discharge.

Add your DC loads

Enter amps and hours per day.

Assumptions and limits
  • Usable depth of discharge assumed 85% for LiFePO4 and 50% for AGM/lead-acid. These are common published guidelines, not a specific model's rating.
  • Energy figures use 12.8 V nominal.
  • Ignores temperature derating. Cold reduces available capacity, and most LiFePO4 batteries restrict or block charging below freezing. Check your battery manual.
  • Ignores inverter losses. Size AC loads with the inverter calculator and add that DC draw here.
  • Does not account for charge acceptance limits, cable sizing, or BMS current limits.

This is a planning estimate, not an engineering specification. Confirm every figure against the manual for your exact equipment. Wire gauge, fuse sizing, and breaker sizing are safety items. If you are not certain, have a qualified RV technician or electrician verify the install.