Saturday, October 10, 2009

How I got more from a gas generator

Our solar system was - to put it kindly - poorly designed. We're retrofitting it now, but for five years an inadequate solar array has tried manfully to fill a grossly oversized battery bank and consistently failed. The wonder is that the batteries lasted even as long as they did. Needless to say we run the generator a lot.

This actually worked - sort of - while there was only one or two people here and no large appliances. That has recently changed, and the system's inadequacies have made themselves felt. Over the past couple of months I've run into an extremely annoying problem where the generator's 20-amp circuit breaker would pop every five or ten minutes during bulk charging.

The inverter has an eight-gauge cable coming out to the generator, with a three-prong plug to connect to a 120-volt outlet. For years this was enough, but now no matter how I reset the inverter the system demanded more than 20 amps. I thought maybe the problem was with the circuit breaker, but replacing it gave no relief. Also, since we also used the generator to run the well pump, it seemed like a terrible waste of gasoline not to simultaneously charge the system and run the pump. But this was no longer possible. With more people in the gulch, all of whom used what seemed to me like a great deal of water, every time I checked the cistern it was damned near empty. It was really getting under my skin.

Though nominally responsible for maintenance I am, alas, no electrician. It was all a mystery to me, what was happening or how to fix it. But a friend offered an interim solution, at least to the generator problem.This generator, and every other generator I ever paid attention to, has a four-prong 240-volt outlet that I never use. My friend sent me the graphic above and told me that I could get 120-volt power from it at higher amperage if I wired a plug using only three of the connections: Green, white, and one black. This would allow me use of the 30-amp circuit breaker, and also let me simultaneously run the well pump off a 120-volt outlet. The plug I needed to buy was expensive - it turns out this particular plug design is peculiar to generators - but when I followed his advice it worked out extremely well. I've been running it this way for the past couple of weeks with no more popped breakers and no more empty cistern. Success!

1 comment:

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