How to Colonize an Asteroid
The
most used type of radio service in much of the world is the commercial broadcast
bands on AM or FM, such as what you listen to in your car or at work. Long
before I built the shed, I built a solar power system dedicated to powering
a "boom box", and it was the first solar system installed in the shed.
At the time which I built this system, solar cells were very expensive, and this was one costly project - if you compare the dollars spent to the milliwats of power produced, but it's cool! The solar array consists of 24 1.2 volt amorphous silicon solar photovoltaic cells, hand soldered into a 2X12 matrix (2 banks of 12 cells each in parallel). On paper, this system should deliver about 14 1/2 volts under full sun. It actually averages about 12 volts (Maybe only 10 on a cloudy day).
The blocking diode drops it to between 8.5 and 10.5 volts on the batteries. The batteries are 7 1.25 volt Ni-Cad "D" Cell rechargeables. There is not enough power to run the tape deck, but the radio will operate for about 6 hours on a full battery charge (less with the volume cranked up - Rock and Roll sucks the most power, but I usually listen to classical music and it works pretty well).
This system has been functioning for about 10 years now, but I did have to replace the batteries about 3 years ago. It does not require a charge regulator, as the current will not go high enough to totally charge the batteries. When the battery voltage surpasses the voltage on the panels, no more current will flow, and the batteries stop charging.
