Maker Factory ELECTRONICS EXPERIMENTS BOX Manual page 47

Circuit 24: Solar light with battery
Setup information
Install the two diodes as shown in Fig. 2.24. Then install the resistor and connect the two AA battery
holders. Finally connect the solar cell. Check the placement on the board again and only then connect the
rechargeable batteries.
Experiment
Free solar power is convenient only if it is always available – meaning, whenever there is demand, not just
when the sun is shining. A simple approach is using batteries. Whenever the sun is shining, the battery is
being charged. The stored electrical energy can then be recovered at any time.
When the circuit starts and the batteries are empty, the red LED remains dark at first, also, when the sun is
shining. The solar cell will initially charge the batteries. Once the batteries have a sufficient charge, the LED
will glow steady, regardless of whether the sun is shining or not. As explained in the previous experiment,
you could charge small devices instead of the LED with your free energy.
Components required:
1 x solar cell, 1 x red LED,
1 x BAT 85 Schottky diode,
1 x 220 Ω resistor,
1 x breadboard, 2 x NiMH bat-
teries with AA battery holders
Fig. 2.24: Solar light with battery
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