How many amps can I pull?

[squarebob]

Bio - Did you ever get this project going? I am interested in doing a project along these same lines. A standard 63 amp 10si puts out approx 46 amps at 3600 RPM. So 46 x 14.5 v = 667 watts. A direct coupled 3 HP engine should have no problem pulling this load unless I am missing something. I would put a switch in the circuit to allow the engine to warm up prior to energizing the alt.

Bob

[BioHazard]

Unfortunately I haven't had a chance to put this thing together yet, I've got the alternator and the engine I just need to fab up a drive system. Most of the parts kinda got lost for a while as I've moved my shop twice since I made this post...

I was hoping to import some ready made small 12v generators using this same engine using a PMA, but unfortunately the talks with the company in china didn't go well...

[Tom Reed]

I built one with a 5hp Tecumseh and 10si, but it is belted 7" on the engine to 4" on the alternator. At this ratio the engine needs to be rev'ed to full rpm's before the field wire can be plugged in. If the engine is accelerated from idle as soon as the Alt cuts in it kills the engine. What I do with mine is connect to the load, start the engine, allow it to warm up a bit and then rev the engine and plug the 2 wire side connector into the alt to start charging. It runs around 1800 rpm to reduce noise and fuel consumption.

A 3hp direct drive will probably work ok. I build mine to extend the runtime of a 12v inverter/battery system that ran my house during extended outages. I used to live in the Redwoods and when big storms came through the power would go out for a week at a time. It did teach me how to live off-grid though.