Solar cell to the radio station
In Holice, you may have seen beautiful solar panels on the stock exchange. There are no limits to the invention, so the idea is directly offered: to power the radio with solar energy, whether portable, mobile or stable operation.
One radio station operated in this way can be seen at Viktor OM3WIK's cottage below Rysy at an altitude of 2250 meters.
The efficiency of solar panels has increased much with the development. Myth, that the solar panel out of direct exposure to the sun does not give any current long ago fell. In fact, its capacity is around even with indirect sunlight 60%. Solar panels come in certain sizes, nominal voltage and current, of course. Panels with a voltage of 18V and a current from 250mA to 1000mA are the most suitable for our purposes.
Due to the price of solar panels, those with lower current are more available. Panel with dimensions approx 30 x 30 cm is able to deliver at full irradiation 250mA current at no-load voltage about 20V. It's not big, so it can be easily used for portable.
The capacity of the solar panel alone would not be sufficient for reliable operation with outputs above 1W (it must be remembered, that the solar panel may not always be effectively irradiated). Therefore, we will use it as a source of constant current, which we will charge the batteries of the radio station.
The connection with the L200 circuit serves as a constant current source, which is cheap and easily available. In addition to it, we only need a minimum of other components. Capacitors C1 and C2 are blocking. We use resistors R1 - R4 to determine the magnitude of the current. Their value can be calculated for any current according to the formula R = 0.45 / I [ohm; -, A]. Pre 200mA (to cells 2Ah optimal charging current, is resistance 2,2 ohm). We choose other resistors in this way, that we are also in indirect lighting and last but not least (at dusk to darkness) “they squeezed out” last mA from the article. So we choose the last resistor for a current of about 25mA, that is 18 ohms.
The milliammeter at the outlet serves as a control. It's good to have him involved and check back from time to time, whether there is a current drop. if yes, the solar panel is insufficiently lit.. The output is connected to the battery, which powers the radio station (can be internal, then terminate the cable with the appropriate connector, or external, then terminate the cable as needed, for example with crocodile clips).
The connection is an ideal accessory for portable QRP operation, whether on HF or VHF. Remember the stations, which were instantly lost from the converter, lebo im “out of flashlights”. I guess them! They should have a solar cell with them and recharge their batteries, HI.
