How to Determine Correct DC to AC Inverter Power Rating for 800-Watt Load

Question:

I have a 800 watt power inverter powering a 1/4 hp motor, running a knife sharpening machine, off my 12v auto battery. It is beeping. Is this a sign the inverter is not giving enough power? Or is the battery the wrong battery for the application? I have a 2010 Honda Odyssey EX. 800 watt inverter Cobra powering, HP 1/4 motor, HZ 60, V 115, A 5.3, SFA 5.9, SF 1.35 Any help your can give me is much appreciated.

asked by: Richard S

Helpful Expert Reply:

It is never an ideal situation to use a device continually at its absolute maximum capacity. Since you are powering an 800-watt motor with an 800-watt inverter it is definitely being strained and that is the cause for the inverter's alarm.

Ideally your inverter will have much more capacity than the connected device requires. It is definitely not a good idea to use an 800-watt inverter with an 800-watt device. All devices will draw more peak power than their continuous rating suggests.

The 1000-watt Wagan Power Inverter # WC3720 can deliver 1000 continuous watts so this unit will give you some safety margin.

helpful expert reply by: Adam R