Inverter Current Draw Calculation

QUICK: Divide watts by 10.

  • For example, your 240V appliance shows a rating of 300W.
  • 300 / 10 = 30A
  • This appliance will draw 30A from your 12V batteries when running through an inverter.

DETAIL:

  • Watts are Watts and remain the same whether running from 240VAC or 12VDC through an inverter.
  • Inverter efficiency is approximately 85%
  • Watts = Volts x Amps
  • So, a 300W appliance, running on 12v:
    300W / 12V / 85% = 29.4A