Inverter: Trace SW2512, sine wave

Battery Maintainer: DeSulfator DS-1000


AC Mains: 120 VAC

to house circuits

Dual Wiring

Our electrical controls, master switches, metering, and inverter are housed in an insulated compartment that is attached to the north side of the house. Batteries are in a separate space below the other electrical equipment. The battery space is insulated with 4 inches of foam insulation on all sides. EPDM rubber sheets line the battery area. A 4 inch plastic pipe vents to the outside. A positive ventilation fan is in the future. Both spaces are well vented to prevent buildup of heat or gasses.

Originally, our AC power was from a Trace 2512 modified square wave inverter. We decided to upgrade to a sine wave inverter. Since we run some 12 VDC appliances, we wanted to keep our nominal system voltage at 12 VDC. Energy Outfitters found us a 12 VDC Trace SW2512 sine wave inverter, and we were good to go. Input from the batteries is through a 400 amp, fused disconnect.

The house is double wired for both 120 VAC and 12 VDC. The DC wiring is #12 (3 mm2), and the AC wiring is #14 (2 mm2). Most of our lights are 12 VDC. The circuits are wired through separate breaker panels. Both voltages are available in each receptacle box. Different plug patterns eliminate the possibility of plugging AC into DC, or vice versa.

As of now, we have no plans to increase our electrical generating capacity. We have never had to have any generator other than PVs and wind power. We have always lived within our energy generating capacity. Our motto is, "Keep it simple." Complexity only adds more things to possibly fail.

Greenhouse AddOn

We decided to live in our underground solar house for a year or two before we built our attached greenhouse. Then, if we needed extra heat, we could vent it into the house. After a couple of cozy winters, we knew that the passive solar design features of the house were adequate, and no backup was needed. So we focused the design of our greenhouse primarily on the plants' needs, not ours.

We used the retaining wall at the west end of our house as the back wall of our 24 by 12 foot (7.3 x 3.6 m) greenhouse. Since this wall is concrete block, insulated away from the dirt, it also serves as a heat sink. We used 3 inch (7.6 cm) square aluminum for the framework since, in past greenhouses, we found that untreated wood tends to deteriorate over time. We garden organically, and did not want to use treated wood.

We used recycled 34 by 76 inch (86 x 193 cm) single pane, tempered glass for the south facing front and the single slope roof. The glass is held in place with glazing tape and 3 inch aluminum strips, screwed to the framework. An 8 foot (2.4 m) sliding glass door—also recycled—finishes the east end, while the west wall has three large windows. Both the east and the west ends have vents with automatic, heat-operated openers. Total cost was less than US$2,300.

Besides vegetables, citrus trees, and the seeds we start for our garden, the greenhouse also houses a hot tub. The tub is actually a 5 foot (1.5 m) oval, rubber-type stock tank. We plumbed the tub to a small stove that sits outside the greenhouse. Made to our specifications by a local shop, the steel stove is shaped like an inverted U, and has double walls that serve as a "water jacket." Water from the tub enters the stove at the bottom, and through natural convection, exits at the top.

It takes an arm load of wood and a few hours to get the tub to about 100°F (38°C)—about 10°F (5.6°C) per hour. We use a Magnum 350 aquarium pump and filter system, plus Baqua Spa products to keep the water clean. We opted for this water treatment system because it is both bromine and chlorine free, and doesn't take a lot of fussing.

During the summer months, we move most plants outdoors. A shade cloth covers the south side and roof to prevent overheating. Future plans call for a solar water heating system to provide hot water for an "outdoor" shower, as well as to heat the spa on sunny days.

McCoy/Reising Greenhouse Costs


Cost (US$)

12 Aluminum box beams, 21 ft., 3 x 3 in.


16 Aluminum straps, 16 ft., 3 x 1/4 in.

DIY Battery Repair

DIY Battery Repair

You can now recondition your old batteries at home and bring them back to 100 percent of their working condition. This guide will enable you to revive All NiCd batteries regardless of brand and battery volt. It will give you the required information on how to re-energize and revive your NiCd batteries through the RVD process, charging method and charging guidelines.

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