Solar Installation

For the past 25 years, I've been reading and studying renewable energy with the goal of one day having my home powered by renewable energy. I've spent many long hours reading and studying articles about solar energy, geothermal energy, hydroelectric production, wind power, and even articles on using waste heat to provide power.

After even more research and lots of calculations, I finally installed a solar panel system to product electricity. With an all electric house, this system provides anywhere from 25% to 35% of our daily electricity usage. Besides installing more solar panels, there's a few more renewable energy projects I plan to complete to increase those percentages even higher.

  • Convert from electric water heater to solar hot water system

  • Convert all-electric baseboard heat to radiant infloor heat using geothermal heat pumps

  • Convert well pump from 240 volt AC to DC power
    • March 2008 update: Grundfos SQFlex (6 SQF-2) Submersible Well Pump on hand - waiting to be installed. This model can pump 6 gallons per minute from a 390' well, and operates on a voltage range of 30-300VDC. My well is around 300 feet deep, so this and a 1,000 gallon water tank (also on hand) should suffice.

  • Convert inground pool pump from 110 volt AC to 240 volt AC (better efficiency)
    • May 2005 update: New high efficiency 240V pump installed - electric power consumption drops a bit!

  • Install wind powered generator to harness seasonal spring, winter, and fall winds

  • Reduce central air conditioner use by installing whole house fan (and eventually replacing unit with geothermal heat pump)
    • June 2005 update: Whole house fan installed; provides primary cooling during most of year
      (except a three week period in July/August where daytime temperatures reach 90+ degrees).

  • Increase battery capacity from 1-hour backup system to multiple day capacity; Goodbye electric company!

Here's photos of my renewable energy system. Many thanks to Robin Gudgel of Outback Power Systems and Eric Wahl of Colorado Solar Electric for their help in getting my questions answered.

Solar Panels In The Sun!
A 3.6kW system making electricity from the sun.

20 Sanyo HIP-180 solar panels (48 volts DC, 180 watts each, 3,600 watts total). These panels are arranged in 4 rows, with 5 panels in a row. The top two rows form one DC circuit group, and the bottom two rows form a second DC circuit group. The unused TV antenna will be coming down one of these days; birds like to perch on it and dirty up the panels.

Another view of the solar panels, showing the combiner box location.

Under the overhang is the combiner box, which is the one of many safety related hardware devices in this installation. The electrical code requires at least one way of shutting off the solar power; my system has three. I won't have to walk around the house to turn off the power if I'm working on the system. I also don't like walking through a dark room to use a pull chain light. I've seen those installed recently in new $200,000+ homes (talk about cutting corners), but that's another story. To the right of the combiner box is room for two more combiner boxes.

Outback PSPV Solar Circuit Combiner Box (Exterior).

This box combines the solar power from the smaller wires to two larger wires. The circuit breakers inside also serve as a safety disconnect.

Outback PSPV Solar Circuit Combiner Box (Interior).

The smaller wires are 10 gauge, and the larger wires are 2 gauge. The larger wires are used to reduce voltage loss between the solar panels and the inverters. I could have used smaller wire, but would need another solar panel just to make up the power loss.

Conduit Run.

The solar power circuits travel through 2" conduit along the back of the house to the box near the electric meter. The box has disconnect switches installed on one side, with room for additional disconnects to be installed on top. The box also has lightning protection to divert any lightning strikes to a newly installed ground rod.


PV Disconnect and Lightning Protection.

The electrical code requires a disconnect switch at one of 2 places, either inside the building nearest the point of entrance of the system conductors or outside the building. If the solar disconnect is not located near the utility company's meter, then a plaque is required by the front door stating where the solar disconnect is located. I also have lightning protection for each circuit coming from the roof. I also have a spare 2" conduit leading into the house for future expansion. From here, the system is also tied into the house grounding system.

Solar Disconnect Pullout Switches.

Each disconnect switch kills the power coming from one combiner box. The second disconnect switch is for future expansion.

Outback PSDC and MX-60 Charge Controllers.

This is the DC circuit breaker box where power from the solar panels join the battery power. There is also a GFCI circuit breaker in case of a short circuit with the solar panels on the roof. The two charge controllers adjust the voltage from the solar panels to get the most power from the sun and to keep the batteries charged.

Outback GVFX 3648 inverters with covers off.

The inverters do all the work converting DC power to AC power. When the solar panels don't produce enough electricity needed by the house, they pass electricity from the utility company to the house (buying). When the solar panels produce extra electricity, the inverters pass the electricity to the power company (selling). These inverters are specially made for grid-tie applications and stop selling if utility power is no longer available (like during a blackout). During a utility company power outage, the inverters draw power from the solar panels and the batteries. I currently have enough batteries to provide about four hours of power if there's no sun.

Outback PSAC.

This is the AC circuit breaker box where power from the utility company mixes with newly made solar power. Circuit breakers are used to control power going to and coming from the inverters. The bypass switch will disconnect the inverters from the rest of the house if necessary (for system maintenance) and the house is then powered by the electric company.

Outback Hub-10.

The main inverter communicates with the other inverters and charge controllers to provide the best power output possible. The Hub-10 allows up to 10 items to communicate with each other. The Hub-10 is also connected to a network jack that leads to a remote monitor upstairs.

Outback Mate - BUYING.

This is the remote monitor located in my home office on the second floor. From here, I can control the inverters and battery charge controllers in the basement, and see how much solar power is being produced. This picture was taken early in the day before the sun was shining directly on the panels, so it shows I'm BUYING electricity. Later in the day, it switches to SELLING.

Outback Mate - SELLING.

This photo shows the solar panels producing more power than I'm using, so we're SELLING electricity to the local electric company (basically making the meter go backwards).

With the Outback Mate, I can also use a computer to monitor and control the renewable energy system. WattPlot is an excellent program that keeps track of energy production and consumption, with data capture and logging down to the second, and also creates graphs and spreadsheet files. There's also a remote feature that allows real-time viewing of the WattPlot screen from another computer on a network.

I also use another software program to show energy production. Winverter from RightHand Engineering isn't as robust at data collection or data logging as WattPlot, but it presents information in a nice colorful display (dashboard gauge style) where a quick glance can tell if the system electrical load is nearing the inverter power limit. WinVerter provides a simple text based webpage to show electrical production (updated every minute) that can be uploaded to a web server and viewed over a network.

A screen capture of the WattPlot program is on the Current Solar Production page.