Maker Factory ELECTRONICS EXPERIMENTS BOX Manual page 149

Circuit 126: Solar charger for two AA batteries
Setup information
Install the diode as shown in Fig. 2.126. Connect the solar cell and the two AA battery holders. Check the
placement on the board again.
Experiment
If everything is wired correctly, you can safely go ahead and insert a NiMH battery into each of the two AA
battery holders. However, charging will start only starts, if each AA battery holder contains a battery. When
full sunlight falls on the solar cell, the battery is charged with about 15 mA, the risk of overcharging a mod-
ern NiMH battery is thus very low. If the solar charger is not constantly exposed to full sun, the batteries can
be kept in the holders. That way, the batteries are basically always charged and ready for use.
The circuit diagram for this experiment is shown in Chap. 3, Fig. 3.126.
Components required:
1 x solar cell, 1 x BAT85
Schottky diode, 1 x breadboard,
2 x AA battery holders
Fig. 2.126: Solar charger for two AA
batteries
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