Pleasing the Neighbors
Here in a small suburb not far from New York City, dreams of massive solar arrays with finely tuned heliostatic trackers are just that, dreams. To keep myself out of trouble with the neighbors and anyone they decided to haul into the quarrel, I decided to make a small addition to our existing deck.
The heart of the system is comprised of four ARCO Quadlam Panels available from Solar Electric. Wired in series, these panels are rated at 17.1 volts at 5 amperes in full sunlight. I find this to be a little off the mark as I have recorded many instances of 6 ampere output on clear days. The panels have been producing 20 to 30 amp/hrs per day during June. These figures are for days with relatively little cloud cover. A very cloudy day can yield as little as 6 to 8 amp/hrs. I mounted these panels to the deck railings using brass hinges. A strut supports each panel and using struts of different lengths allows me to match the sunís elevation. This will be done four times a year.
Batteries and DC Loads
The panel array feeds into an 8 amp/hour charge controller made by Collins and Associates, Inc. I have the controller set for 14.5 volts. I have found this to be an optimum setting for the batteries I use. The main battery is a Sears deep cycle marine battery (#96522 ) capable of storing 115 ampere hours. This battery is under the same deck that the panels are mounted on. An odd twist to this system is that there is another sealed gel cell in my room that is wired in parallel to the main battery bank This battery holds 15 amp/hours, making the system's total capacity 130 amp/hours.
This second battery was needed due to the fact that my room contains an ICOM 707 HF Amateur radio that can draw 15 amps on transmit. I also have an Alinco DJ-580T VHF/UHF transceiver with an RF Concepts RF amplifier. When transmitting, this VHF/UHF radio and RF amplifier combination draws 6 amperes. Unfortunately, I could only run 14 gauge wire from this room to the Sears main battery due to appearance restrictions. The wire had to be run along the outside of the house. Without the second, smaller battery pack in my room, the voltage drop at 10 to 20 amps through 14 gauge wire would be quite severe. I chose a sealed gel cell to avoid any gases a regular deep cycle battery might produce since the pack does sit inside living quarters.
In addition to the DC loads on the system, all of the lighting in the basement is powered by this solar system using a 300 watt Power To Go inverter made by Clearline Concepts Corporation. The basement contains three 80 watt fluorescent dual tube lamps and one 40 watt single tube lamp. The inverter is a modified sine wave inverter and the square wave it produces does not seem to bring the lights to their full brightness when compared to grid power. Each of the doubles draws 4 amperes at 13.5 volts through the inverter. The single tube lamp draws exactly half this amount, 2 amperes. These figures confirm the notion that the bulbs are not getting a full 80 or 40 watts and therefore are not as bright as possible.
The inverter is wired to the battery using 30 feet of 6 gauge wire. Six gauge wire is excessive for this application, but I plan to upgrade to a larger inverter in the future. The AC output from the inverter powers a homemade switchbox. Each of the lamps is on its own switch.
The inverter and the switchbox lie at the far corner of the basement in relation to the entranceway. I ran a wire from the remote control port of the inverter to a switch panel by the door. This allows the inverter to be turned on when entering the room. I leave at least one of the fluorescent light switches on so that when the inverter is remotely powered up, the entrant has light with which to cross the basement and access the switch panel. Before this addition, I had to walk across the basement in total darkness to switch the lights on.
If I used all of the lights and all of my ham equipment (assuming 50/50 transmit/receive ratio) for one hour a day, the total current drain would be about 30 amp/ hrs. Keep in mind that inverter efficiency is about 90%, so this 30 amp/hr figure is low. I rarely use everything for a good solid hour each night. I use 10% to 40% of all of the loads about 4 times a week for just under an hour each evening. Based on this, I expect an energy surplus over time. A second 115 amp/hr marine cycle battery may be added to give the system more storage depth.
The inverter has a 30 amp fuse built in. In addition, the wire run to the battery is fused right at the battery lest there be a short somewhere. Each of the DC load centers is fused at the respective battery. The panel feed to the battery is also fused at the battery on the other side of the inverter (i.e., closer to the panels than the main battery). I always fuse right at the battery. Nothing scares me more than the thought of a shorted battery creating a momentary surge of hundreds of amperes with great potential for a minor explosion.
The panels were $400.00 once the frames were added. The charge controller was about $35.00. The Sears battery was $80.00 and the inverter was priced at $80.00 also. I am sure that I spent about $50.00 on wire and other unseen necessities.
The Next Step
Since I am seriously considering adding another large battery and taking into account that on average the system creates a power surplus, I plan to add some more loads to the system. My room is the first target. Right now I have one 100 watt bulb, one 75 watt, and two 60 watt bulbs. They are all incandescent. I would love to put in 12 volt fluorescent bulbs as replacements, but I have found the cost to be high. One outfit wanted $49.95 for a 20 watt fluorescent (equivalent to a 75 watt incandescent). In light of this, I will be purchasing one 27 watt, one 20 watt and two 15 watt fluorescent bulbs designed for 120 volts AC. In my area every hardware store carries them for about $20.00 each. Of course, this will require an inverter to be placed in my room.