This article will talk about what needs to be done so that the radio can work from solar energy.
When traveling to nature, the author often takes a radio with him to listen to music and not to put down the battery of the car and phone. However, there were situations when outings on the nature were delayed, and the batteries in the radio were not enough for the whole time. After such a situation, the author came up with the idea of a solar battery.
Materials used to create a solar radio receiver:
1) solar panel with characteristics of 4-5 V and 80 mA
2) Battery powered FM radio
3) Schottky diode BAT43
4) NiMh batteries with a capacity of at least 800 mA \ h
5) soldering iron and related consumables
Let us consider in more detail the design and stages of modernization of the radio receiver for its operation from solar energy.
To begin with, the author dismantled one of the garden lights to get out of it a solar panel, which is just suitable for powering rechargeable batteries. Although, it could also be assembled from solar cells ordered on eBay.
The author wants to note that if you use a battery from a garden lamp, you need to pay attention to the number of strips on the element. The fact is that there are several models of fixtures, some cheap use weak solar panels with 4 stripes, and they are two times weaker than that of the author. Therefore, for the normal operation of the radio, you need two of these batteries connected in parallel.
The solar battery is glued to the lamp housing, so the author had to try hard to pull out the solar cell and not damage it at the same time.
If your radio has a socket for connecting a power supply, you can simplify the connection system. To do this, just solder the appropriate plug to the solar panel. However, with this approach, the battery will not be charged, since the socket provides protection that disconnects battery power when the power supply is connected.
Since the author wanted the solar battery to charge the batteries, he opened the body of the radio and soldered two wires. The negative wire can be soldered anywhere to the total mass, and the positive wire must be soldered directly to the terminal. In order to observe the polarity, the author simply used wires of different colors.
After upgrading the radio, the author proceeded to connect the solar battery. For starters, the Schottky diode was soldered to the positive output on the solar panel. This diode prevents reverse current from the batteries in low light conditions of the solar battery, thereby saving energy in the batteries. In case you do not have a Schottky diode, you can use its analog KD521A like this. However, it is better to use Schottky, since it has minimal energy consumption.
After the solar panel was connected to the radio system, the author mounted it on the back wall, which was perfect for these purposes. After such an upgrade, you can listen to the receiver almost around the clock, since during the daytime the batteries manage to fully charge from the solar cell.
