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array up on the roof, we were glad we did all the wiring on the ground, because working space on the 2 by 12 planks was limited.

Next we positioned the array towards true south— that's about 18 degrees east of magnetic south in southern Oregon. Then we screwed the array down tight through the wiggle molding to the 2 by 4 rafters. We used six, 3 inch long, 3/8 inch (25 x 10 mm) lag screws to attach the array to the roof.

After the array was in place, we were ready to get the wiring into the house. The PV wires were run through Liquidtight conduit into the attic via an attic vent. To get the wire runs through the vent, all we had to do was pull a corner of the vent's metal screen back. Once in the attic, the

Six lag screws attached the PVs and homemade rack to the After we de-installed the system (to move), we filled the holes and then put the screws back in.

Six lag screws attached the PVs and homemade rack to the After we de-installed the system (to move), we filled the holes and then put the screws back in.

patio roof. with sealant

wire runs entered a combiner box that transfers the PVs' output to a pair of #2 (33 mm2) copper wires.

The #2 wire ran in conduit through the attic, and dropped through the ceiling into the closet in my office, where the rest of the system's components were located. At this junction, we had to drill a 13/8 inch (35 mm) hole for the conduit. Don't tell our landlord—we patched it before we left. We think it was a minor thing to fix for installing the system safely.

After the PV wiring was inside the office via conduit, we had to get the wires inside the wooden box that houses all the RE equipment. Using a 13/8 inch drill bit, we made a hole in the box for the conduit.

Before we started wiring up the DC breaker box, charge controller, inverter, and amp-hour meter, we popped the knockouts on the back side of each unit. Next we mounted the components onto the box, and marked where the knockout holes were. Then we drilled out the holes and permanently installed the components on the box. Each component has all its wiring concealed inside the box—it's safe, tight, and clean looking.

The PV wires were fed to a Square D breaker box that has two, 30 A breakers. The first breaker functions as a PV-to-controller disconnect and breaker. The second breaker is the controller-to-battery disconnect and breaker. These breakers' wire runs are made with #6 (13 mm2) copper wires. After we had all the gear affixed to the box and connections made between PVs, breakers, and controller, it was time to work on the batteries.

We made the battery cables using #2/0 (67 mm2) welding cable, lugs, and color-coded heatshrink tubing. This step requires a crimper, torch, vise, and solder. The nice thing about making the cables from scratch is that you end up with exactly what you want without unnecessarily long cables.

First the batteries were connected in parallel with short cables. Then the positive battery cable was connected to a Class T, 110 A fuse and the inverter. The negative battery cable was connected through a shunt to the inverter. Connections between the batteries and charge controller were made to the major positive and major negative. Connecting the battery cables to the inverter was convenient because the ProSine 1000 accepts battery connections from many angles. Once all the battery connections were made, we made the five connections for the amp-hour meter, fused it, and programmed it.

System Performance

We've been really happy with the system's performance. It's functioning just as we expected without any glitches. We've lived with the system for over a year now. The loads and sizing figures have proven accurate. Our system delivers enough energy in the summer months to run my office patio roof. with sealant renter's PV system

This hole we made in the ceiling for the conduit was the only interior impact our PV system had on the house.

Go For It!

You don't have to own your own home or be wealthy to live with renewable energy. It's possible to install a PV system and still tread lightly on your rental with creative system design and installation. My advice to anyone who wants to live with a renewable energy system is to start by making your home as energy efficient as possible, and then go for it!

Access

Eric Grisen, Home Power, PO Box 520, Ashland, OR 97520 • 541-512-0201 • [email protected]

Brand Electronics, 421 Hilton Rd., Whitefield, ME 04353 • 207-549-3401 • Fax: 207-549-4568 •

[email protected]www.brandelectronics.com • Digital power meter

Concorde Battery Corp., 2009 San Bernardino Rd., West Covina, CA 91790 • 800-757-0303 or 626-813-1234 • Fax: 626-813-1235 • [email protected]www.concordebattery.com • AGM batteries

RV Power Products, 12598 Fortune Way, Suite K, Vista, CA 92083 • 800-493-7877 or 760-597-1642 • Fax: 760-597-1731 • [email protected]www.rvpowerproducts.com • MPPT charge controller

Shell Solar Industries (formerly Siemens Solar), 4650 Adohr Ln., Camarillo, CA 93011 • 800-272-6765 or 805-482-6800 • Fax: 805-388-6395 • [email protected]www.shell.com • PVs full-time. In the winter, I use the grid about half the time (see seasonal output comparison table on page 28).

It's been an educational and empowering experience for us to run my office with solar electricity the past two summers. Although the system is modestly sized, we're very happy with it, and we'll be adding more PV to it. Our goal is to incorporate some of the components we have into a larger system that will cover all of our loads.

Sometimes we have surplus energy in our system. Tiffany and I have had a good time using up the surplus by having friends over to watch solar powered kayaking videos or to drink solar powered margaritas from the solar powered blender. As RE professional Bob-O Schultze says, "The only way you can waste renewable energy is to not use it."

Why did Tiffany and I choose a battery-based RE system over a utility-intertied system? We wanted to build a small system that we could take with us when we moved. Our setup guarantees that if we live off-grid, we'll have lights at night and I'll be able to work from a remote location. We also didn't want to make the wiring modifications to a rental that utility-interactive systems often require.

Solar Energy International, P.O. Box 715, Carbondale, Colorado, USA 81623 • 970-963-8855 • Fax: 970-963-8866 • [email protected]www.solarenergy.org • Hands-on education

Xantrex Technology Inc., Distributed Power Markets, 5916 195th St. NE, Arlington, WA 98223 • 360-435-8826 • Fax: 360-435-2229 • [email protected]www.xantrex.com • Inverter, AH meter

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