Lately we have been taking some time off from intensive gardening to do some outreach, some electrical infrastructure and transportation upgrades, and some tying up of loose ends.
For instance, the “poopane” project, our experiment in producing “frac-free” methane on a home scale, is beginning to pay off now that the weather has warmed to a range suitable for the maximum growth of anaerobic bacteria. The first 50-gallon production tank appears to be nearly half full of methane/carbon-dioxide mix, with some of it beginning to bubble through the lye-water in the collection tank that removes the CO2, partly filling it also. Soon I’ll have to hook up the small used compressor I bought to transfer some of the CO2-scrubbed gas into a pressure tank for later use. Our conclusions so far: A) It takes a lot of heat to optimize gas production, B) Maybe we should paint the production tanks black to optimize heating, C) Maybe we should add a layer of glazing around the tanks to minimize heat loss at night, and D) Maybe this is more trouble than it’s worth on our tiny scale. But we’ll keep plugging away at this to refine the process and report back again.
In transportation news, the 1971 G.E. Elec-trak (electric garden tractor) and 1979 electric Porsche now have an upgraded solar charging facility. They had both been charging from the thirteen Kyocera KC-120 and KC-130 solar panels that comprise our home’s sole electrical source. But on some summer days we wanted to use the electric car or mow the orchard when the weather wasn’t really sunny enough to share the available power. So we added three new Kyocera KD-135 panels on a pipe rack alongside our driveway (a terrific solar spot) and wired them to a new Outback Flex-Max 60 charge controller in the sheep shed. From there the power can be routed to either the car, the tractor, or the house, depending upon where it’s most needed. This has really boosted the car’s charge rate. Previously the car ran from three KC-120s wired in series to produce about 60 volts maximum, flowing into what ranged from 52 to 55 volts in each of the car’s three paralleled battery banks (which are switched to full series wiring when we want to drive it). This close voltage match meant that the charge rate was usually pretty slow, often taking a week to reach full charge after a 26 mile round-trip to town. Now we can take advantage of the Outback controller’s ability to use the high-voltage input of six Kyocera panels, switched into series, to turn excess voltage into more amps. This gives us DC charge rates that are often higher than the rates we could obtain using the car’s on-board AC charger. Now we can fill the car up in less than 3 days, leaving more power for the house and tractor.
And speaking of tractor upgrades, the old-style switched relay speed control system that General Electric used back in the early 70’s was beginning to break down. The tractor had been losing some forward speeds, but one day it also lost reverse in the middle of high-mowing weeds in the sheep pasture. Diagnosing the problem was a nightmare, even for someone who knows what to look for. So we decided to upgrade to late 20th century technology and install a PWM (pulse-width modulation) speed controller. These are usually used in modern electric golf carts, so finding a new overstocked one on E-Bay was pretty easy. Rewiring the tractor took about 3 days, mainly to figure out which wires in the old configuration would still have some function and which parts and wires could be removed. But now it’s like having a brand new tractor. More power, less energy used from the batteries, greater control over both forward and reverse speeds, both hands to operate the steering wheel thanks to a foot-operated accelerator pedal, and “plug braking” to more safely slow the tractor on downhill grades when you ease off on the “gas pedal”. Coupled with the improved charging set-up, mowing for weed control has gotten much easier.
And our outreach efforts at this year’s Midwest Renewable Energy Fair were carried on by Larisa alone this year. She presented her usual workshops on low-energy food processing, food-storage, and year-round gardening to tent-filling crowds. And she got to visit with like-minded friends that we normally see each year at the Fair, trading gardening stories and sharing the woes brought on by an altered climate. It’s great to be able to share what we’ve discovered and it’s equally great to get inspiration, fresh ideas, and support from those who are attempting the same.