Originally Posted by pbiJim
That was actually the first thing that I considered, but I figured that I would look to see if I could just buy one first. I'm not really finding what I want on the open market, so building my own is looking more likely. I have access to a machine shop, so the fabrication end of it is not a problem. Finding the right motor
is looking to be the toughest part. I want something around 1-1.5 hp, small & lite. Maybe like a Wisconsin Robin aluminum
block pull start. I would prefer diesel
, but 1hp diesel
engines are like hen's teeth to find. They seem more rare than sub fractional hp 3-phase motors.
I think the Robin DY23 is about the lightest diesel engine
But you don't want to undersize it anyway -- you most definitely do not want to run these light-duty engines anywhere near their maximum power.
The Robins are really nice units with balance shafts, pressure lube systems, etc. I think you could make a very nice little generator
matched to a 140 amp (or so) large-frame alternator
. The Robin ought to be able to run such an alternator
at full capacity at about 2500 RPM
-- just what you want. Then you just throttle back when you need less than full output from the alternator. At 2000 RPM
it's still producing about 2kW of (mechanical) power (enough to make probably 1.5kW of electrical
power, I guess), so I guess you would be running it at 2000 RPM or less most of the time.
The only engineering you will have to do is to properly size the pullies to get the right maximum mechanical power draw from the alternator at the right engine
The only concern I would have is how to get the heat out of the boat? Air cooled engines produce a lot of hot air, and require a whole lot of cold air to work properly. Or do you plan to run it on deck
If you're going to run it on deck
, then you don't necessarily need a diesel one. You can save yourself a lot of trouble and just buy a little Honda
portable. They make a 1kW one (I own one!) which is extremely light and compact. Just use it with a simple battery charger
matched to the generator's maximum output and you'll be in business.