[VAC] Re: Electrical Independence

["Dr. Gerald N. Johnson, electrical engineer" <geraldj@xxxxxxxx>]

I agree that the limitation will be the size of the charging (and
ground) circuit wire. Make it something like #6 if you can get that into
the connectors and charging will be faster.

My old F-350 doesn't heat while idling either. Needs fast idle to charge
its own battery. Probably doesn't take half an hour from a nearly dead
battery though. You would do well to monitor the battery voltage in the
trailer with a Digital Volt Meter and when that voltage gets to 14.2
volts, then shut down the truck.

Another slightly more fuel efficient method would be to belt an
alternator with regulator to a small gas engine. Say a horizontal shaft
engine from the old reel type lawnmower, probably a couple HP. Crank up
the speed on the engine to 3600 and run about 1:1 on the pulleys. I did
that eons ago with a 2 cycle Jacobson engine, but the engine can only
push the alternator hard enough to produce 20 amps. Just doesn't have
the guts to put out more current. That small engine will run on less
fuel than anything under the hood of the truck, but its another engine
to futz with. The same scheme could be done with an old rotary mower,
just mount the alternator with its shaft vertical through a hole in the
deck, replace the blade flange with a pulley and belt to the alternator.
I've run the horizontal shaft version 24 hours for radio operation on a
gallon or two of gasoline.

Any electricity generated on a small scale usually is close to the most
expensive electricity on the planet. The small scale is always against
super efficiency. Sometimes the efficiency of utility power plants is
legislated rather than true as in California these days.

Gerald J.