A Solar Charging System |
I bought this solar panel cheaply probably because it has a special connector. However it is well sealed, adjustable in elevation, and has a long cable of good quality. It produces 200 MA into a car battery in full sun, and about 1 ampere-hour a day. I have permanently connected it to an old meter box containing a current meter switchable between 20 and 200 MA FSD, and an isolating diode. Note that the meter is labelled "Dosage": it is from an Electro-Convulsive Therapy machine which was discarded in the 1960's! This combination may be used by itself, usually with a lead-acid battery, or with the Current Limiter, which is the smaller box on the left in the photograph. The circuit board for the Current Limiter was originally packaged with a large re-cycled power supply for a different dedicated battery charger. This worked, but I considered it ugly, and re-packaged it in its current form. But later I put it aside as being overkill for that application and replaced it with resistors and a relay. It was modifiied slightly for the Solar Charger to connect the battery to be charged via binding posts, and to insert a shunt resistor so that the Charge Controller can measure the charging current. It can be used with or without the Charge Controller. The Charge Controller is an all-new unit whose purpose is to cut off charging when a selectable number of ampere-hours have gone into the battery. The photo at the bottom is of a battery holder and a 434 MHz transmitter which connects to the DA9S socket pins 2,5 and 6, which has +5V power for it The components of the System Diagram below are described beginning in the next page for the Current Limiter. | |