... wave 2, DC 12V/24V/48V Input, AC 220V output 3, High Efficiency 90% 4, CE Certificate What size inverter should I buy ... of the appliance or power tool determines whether an inverter has the capability to power it. For example, you have a freezer ... ; for example, to keep up with a continuous draw of 1000 watts, you would need a 91 amp alternator) 6V to 220V power inverter