It has been my long desire to move WQ4RP toward 100% Solar/Battery powered status. With the total rebuilding of the radio shack during 2016, it made sense to incorporate a solar system into the new shack. The goals for the power system system were to supply RF quiet power for the entire amateur radio station, including power for the radio(s), peripheral equipment (logging computers, keyers, etc.), and lighting. WQ4RP is often used as a QRP contest station, so the power system needed to be robust enough to supply continuous power both night and day. This post discusses the components that comprise the WQ4RP Solar/Battery Power System:
- Solar Panels
- Mounting system for the panels
- Solar Charge Controller
- Shack Lighting
- Wiring details
Two Renogy 100W 12V Monocrystalline Solar Panels were selected for this project. The two panels were mounted over under style with the use of aluminum L stock purchased from Home Depot. The two panels were bonded very securely to the common aluminum L stock with pop rivets.
Two Renogy 12V 100W Monocrystalline Solar Panels
My first inclination was to mount the panel assembly on the roof of the shack, but I decided not to do that for two reasons. I didn’t want to compromise the new building by drilling holes in the roof, and I reasoned it would be safer and easier to perform quarterly tilt angle adjustments to the panel if it were pole mounted closer to the ground. An 8′ long x 5″ diameter wood post was selected as a mounting post for the solar panel assembly. This post was sunk 2-1/2′ into the ground and secured with concrete. A pole mount was purchased in order to mount the solar panel assembly to the post. This particular mount allows the panel assembly’s tilt angle to be seasonally adjusted for maximum efficiency.
Tycon TPSM-70×4-UNI Pole Mount
The two 100W solar panels were wired in parallel in order to supply charge current to two 100AH 12V AGM deep cycle batteries inside the radio shack. Fifty feet of #12AWG underground power cable was used to supply power to the single point entry (SPE) panel on the far side of the radio shack. All antenna feed lines, control cables, and power cables are routed through this SPE panel in order to maximize protection from lightning.
KF7P Single Point Entrance Panel
The 12VDC output from the solar panel (red and black wires on the top row of connectors below) are routed through a Morgan Control line Arrestor, which shunts any lightning induced energy to an extensive grounding system before the solar power enters the building.
Morgan M-348 Control Line Arrestor
Upon entering the building, the properly fused 12VDC solar power is routed to a MPPT Solar Charge Controller , which is responsible for supplying charge current to the the two large deep cycle batteries. This particular charge controller does not generate any detectable RFI throughout the HF spectrum. The GV-10 charge controller is rated up to 10.5A at 12VDC.
Earlier this Winter, the 7.5A protective fuse that I had installed between the GV-10 controller and the batteries blew shortly after I repositioned the solar panel tilt angle for maximum efficiency. I was impressed that the solar system was providing over 7.5A charge current to the batteries on a Winter day, when the sun was low in the sky! After replacing the 7.5 fuse with a 10A fuse, I have not experienced any further issues with blown fuses.
Genasun GV-10 MPPT Solar Charge Controller
The two 100AH batteries centered beneath the operating table are wired in parallel in order to provide 12VDC power for the radio(s), logging computer(s), and LED lighting. Every positive lead from the battery system is independently fused.
Universal Power Group 45978 12V 100AH Batteries
A 100mv shunt was installed on the negative lead of the battery system in order to provide a signal to a Bayite digital power meter. This allows convenient, continuous monitoring of the battery load current.
100mv Shunt Mounted on Negative Battery Post
The digital power meter is displaying the current being drawn from the battery system during the CQWW160 CW Contest (Jan 2016). The 6.27A load current included the Thinkpad laptop logging computer (5.12A), the Argonaut VI transceiver (0.52A rx), and the LED ceiling lighting (0.63A). The biggest current hog by far was the laptop computer, which exacted a heavy toll on the current budget over the 15 hour night time period (when this picture was taken). This computer has since been replaced with an Asus T100TA netbook, which consumes one-fifth of the power of the Thinkpad!
Bayite DC 6,5-100V, 0-100A Meter with 100mv Shunt
The choice of lighting for the WQ4RP radio shack was a major concern. After a good deal of research, a 12V LED Kohree Dome Light was ordered and installed as a trial test.
Kohree 12V LED Dome Light
The light had to produce sufficient output to adequately illuminate the operating table at night, and it had to be energy efficient. The picture below clearly demonstrates that the operating table is well lit at night. Furthermore, the current draw is just 0.68A with both sides of the lamp lit. A rocker switch on the lamp fixture enables one half of the light to be turned off, further reducing the current draw to 0.34A while still providing adequate illumination of the operating table. An identical LED ceiling light was subsequently installed on the other end of the operating table. This second light stays turned off unless an additional station is set up.
Ceiling LED Lighting Provides Good Illumination with Low Current Demand
The WQ4RP Solar/Battery system has met all of the aforementioned goals during the past year. It is rewarding to know that the station can be activated for long periods of time without the need for commercial or generator power.