Watched video. So simple I could easily build it except for figuring out how much 3000 watts will run & what to connect to the generator? Car battery? Inverter? duh!

All that is real easy.

Amp times Volts equals Watts.

or

A x V = W

150 x 12 = 1800

And based on basic math

A x ? = ?

or

? x 12 = ?

or

? x ? = 1200

So figure you need 1200 watts. You have 12 volts and thus need-- ? x 12 = 1200 makes you need 100 amps.

remember that and its really kinda simple.

and most everything should have a label on it detailing what it needs as far a wattage.

Now let those with real electrical knowledge jump in and teach me the error of my ways on this and get it right for you.

Nemo