Conrad Course material 10025 14 years and over 10025 Manual De Usuario

15.  Step: Storing solar energy 

Experimental set-up: solar module, patch panel, 100 Ω series resistor, red, green, orange, flashing 
LED, 100 µF and 4,700 µF electrolytic capacitors 
 

This experiment also works with little light (shadows, cloudy sky). 

 
Is it true that the low output of your solar module can yield a large amount of energy over a long time 
through reasonable storage of power? The principle of electrical power, invisible for our senses, can 
be compared to and explained by a principle which we can observe with water:  
a water tap (your solar module) that drips over many hours gradually fills a ten-litre bucket with water.  
 
Fig. 47: The principle of energy storage explained on the basis of the dripping water tap: small 
amounts over an entire day fill a large basin. 
 
Over the course of a day with sunshine, a solar module with low output “drips” the power converted 
from the sun milliampere hour for milliampere hour (mAh) into the energy storage. 
 

The unit mAh quantifies the power per hour, in contrast to mA, which signifies the momentary current 
flow. 

 
There are electrolytic capacitors in the educational kit that can store power. The advantage of the 
capacitor storage is that it has a very long service life. But compared to a battery the storage capacity 
is only slight, which for the experiments has the advantage that the principle of storage can be 
observed over a manageably short period of time. The connection wires of the electrolytic capacitor 
must be connected briefly (short-circuited) before the experiment so that the charging function can be 
experienced. 
 

This experiment also works with little light (shadows, cloudy sky). 

 
Fig. 48: Patch panel set-up – use the flashing LED. a) First plug in the small 100 µF electrolytic 
capacitor (the longer connection wire is the positive pole). b) Then replace it with the 4,700 µF 
electrolytic capacitor. What happens after the replacement? The LED doesn’t flash anymore; it takes 
some time after plugging the electrolytic capacitors in before the LED shines or flashes again. If the 
solar module is covered, the LED continues to flash. 
 
Fig. 49: The electrolytic capacitors C1 and C2 and the LEDs can be replaced for the experiments. 
Think of the series resistor R1 when connecting the LEDs. 
 
Series of experiments: 
a) 

Plug the 100 µF electrolytic capacitor in; note the polarity. What happens? 

The flashing LED pauses briefly, then flashes again. 
b) 

Plug the 4,700 µF electrolytic capacitor in. What happens? 

The flashing LED pauses for a longer time, then flashes again. 
c) 

Leave the experimental set-up as in b) until the LED flashes. Then pull the 4,700 µF 

electrolytic capacitor out of the patch panel. Next, shade the solar module. The LED immediately stops 
flashing. Now plug the electrolytic capacitor back into the previous contact rows and continue to shade 
the solar module. The LED flashes although no power is coming from the solar module.  
 
Fig. 50: Experimental set-up: the electrolytic capacitor is replaced. 
 
Ergo: the charge in the “energy storage” electrolytic capacitor is preserved over a longer period. 
 
d) 

If the electrolytic capacitor is charged, the LED flashes. Now disconnect the solar module. 

Observe how long the LED flashes and draws its power only from the storage electrolytic capacitor. 
The larger the capacitor storage is, the longer the LED flashes, even without power from the solar 
module. With a Gold Cap, the missing power supply (e.g., during darkness) could thus be bridged over 
a long period. 
 
e) 

Now leave the previously charged electrolytic capacitor connected to the solar module over 

night (without LED) so that no more light strikes it. The next day, check with a flashing LED how much