Electrical wizards, need some info on inverters

[Deezul1]

I have a inverter that puts out 800 watts continous at 115 volts from 12 volt input. My question is what is the amp draw on the 12 volt side when the full output is being used? I want to wire the 12V hot wire through a relay to control on/off from a switch in the cab. I have a 30 amp relay, is it enough?

TIA

John

 

[klenger]

No, 30 amps is not enough. 800 watts on the output side is in the area of 900 watts on the 12 vdc input side. W = V * A, or A = W / V, so 900 W / 12 V = around 75 amps. These are kind of worst case numbers. 60 - 70 amps is probably more realistic.



You also need to be looking at about 4 gauge wire to connect the inveter, assuming the wire length is not too long. If you never plan on using the inverter at full load, you can use smaller wire and relay, but it's not a good idea because someone else may load it up.

 

[Deezul1]

Thanks for quick reply. It came with 8ga wires 3ft long with battery clips so I was kinda guessing from that on the relay.