Answer
Apr 24, 2026 - 12:34 PM
A helpful rule of thumb provided by PKYS for 12V DC and 120 V AC inverters is that the DC amp draw is roughly 10 times the AC amp draw.
Example: If you run a 120V AC appliance that draws 8 Amps, your inverter will pull approximately 80 Amps from your 12V battery bank. To do a more involved calculation figure that the Watts going in to the inverter equals the Watts going out of the inverter less a bit for inefficiency. So if you have a 2000 Watt output the formula is Watts = Volts x Amps. In this example 2000 Watts = 120 volts x 16.6 amps. On the input side if the battery is 12.5 volts using the same formula 2000 Watts = 160 amps
Example: If you run a 120V AC appliance that draws 8 Amps, your inverter will pull approximately 80 Amps from your 12V battery bank. To do a more involved calculation figure that the Watts going in to the inverter equals the Watts going out of the inverter less a bit for inefficiency. So if you have a 2000 Watt output the formula is Watts = Volts x Amps. In this example 2000 Watts = 120 volts x 16.6 amps. On the input side if the battery is 12.5 volts using the same formula 2000 Watts = 160 amps
