It even looks like with a two pulley setup going from 2" pulleys to twelve, you'd only get about 500 rpm.

Heya Donk,

Was thinkin' about powering your wagon last night. Came to the conclusion that an auto alternator is a poor solution. You'll need too much RPM, resulting in too much "gear up", too much loss.

You need a low speed alternator. Look at the early windmill projects from www.otherpower.com for some home-built low-rpm 3 phase alternators. These could work from a diff shaft directly (dif ratios are in the 4:1 range, turning your ca. 40rpm into 160rpm). A simple belt or chain if more rpm made things easier....

You may be able to use a commercial wind turbine alty or similar tech....

Just a thought.

For a automotive alternator, I'll again suggest bicycle chain. It wouldn't be as noisy as you'd think (the actual running noise of a bike chain is minor, compared to the clickety-click of the free-wheel mech), and chain drives are far and away more efficient than belts or gears (done right 98% is typical!).

I'd go for 2 stage chain (4:1 diff, 48 tooth on the diff driving 11 tooth, driving 48 tooth, driving 11 tooth on the alty).... that's 3000rpm...

J

This whole exercise is fascinating but I'm starting to wonder if it will work at all, at least affordably.

The simple permanent magnet altys described here are where I'd start....

http://www.otherpower.com/otherpower_wind_alternators.html

Your application has ALOT in common with wind power.

I'm about to edit my above post, as I neglected the 4:1 diff ratio...

J

What would be the diameter of a 48 tooth sprocket?

7 or 8". The large cog on a bike. A road race bike might come with as large as a 60 tooth cog. 11 tooth is about as small as the rear cogs come. Get'em off yard sale /junk bikes for real cheap. The big cogs (called chain wheels) almost never wear out, but I'd probably consider new for the small ones, which wear more quickly.

Bicycle chain is always 1/2" pitch. It's light stuff, but will carry a few horsepower reliably with minimal lube. Heavy oils will tend to silence any clatter...

J

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http://www.pulsetech.net/applications/cartruck/misccar_01.html



More to come...........

.

Indeed, solar seems the easiest answer... I think I mentioned it far above... But solar alone would have trouble running much for long, unless the array is quite large.

Lights, a radio, a laptop, easy enough. A small fridge is quite a load...

J

Actually... I suggested the solar/battery set-up in my first post. Lighting runs off the battery(ies) w/ AC/DC converter for the occasional plug-in needs and charging, stove and fridge runs off LP (or plug-in to 110v). Small gas powered genny available for the "just in case" times.

Simple.