How many amps of the battery do I need for this 3000w power inverter ?
If the inverter is 3000w power inverter with dc 12v, 90% efficiency, then the battery you need is: 3000w /12v / 90% inverter efficiency / 80% battery efficiency
If the inverter is 3000w power inverter with dc 12v, 90% efficiency, then the battery you need is: 3000w /12v / 90% inverter efficiency / 80% battery efficiency