Is a 3000w inverter too big?

[Christ]

You could also run dual alternator, or replace your alternator with a higher output generator, depending on how often you plan on using it, and the age of your vehicle.

[chrisgerman1983]

thanks for all the advice I should have gone with a bigger alt when I replaced it... ill have to go with what I have for now.

[ecomodded]

If the Alternator makes 90 amps, once converted it will make 9 amps x 120 volt = 1080w, the extra batteries will allow for larger wattage items, with limited run time.
I think it would run a 1500w power tool off and on without burning up, mind you with lots of off time to replenish the batteries. A larger Alternator would be nice for your set up alright.

[Ryland]

Originally Posted by ecomodded

If the Alternator makes 90 amps, once converted it will make 9 amps x 120 volt = 1080w, the extra batteries will allow for larger wattage items, with limited run time.
I think it would run a 1500w power tool off and on without burning up, mind you with lots of off time to replenish the batteries. A larger Alternator would be nice for your set up alright.

My alternator has a 50 amp fuse on it... but the battery can handle a surge load of 100's of amps without the alternator running at all, it does this every time you start the engine.
If you average out a standard household using 900kwh per month, that's 1,250 watt constant, 24 hours a day for a month, my electric bill is closer to 500 kwh per month or 700 watts constant to run my whole house.