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

 

This experiment should be done with uniformly bright sunshine (or desk lamp). 

 
Fig. 55: Principle of the circuit with blocking diode 
 
With solar charging of an electrolytic capacitor, Gold Cap or rechargeable battery, the charge would be 
discharged again at night via the solar module (see 14

th

 step). Therefore a non-return valve must be 

added in the form of a diode. The diode functions like a valve that only allows the energy to flow in one 
direction and prevents it from flowing in the other direction. 
 
Turn the diode in the patch panel around. The LED doesn’t flash anymore since the current coming 
from the solar module is blocked. 
 

Blocking diodes prevent the storage battery from discharging via an unilluminated solar cell.  

 
 
Fig. 56: omitted 
 
Fig. 57: Patch panel set-up 
 

19.  Step: Charging batteries with solar energy 

To stay with the comparison to water: for the collection tank – and thus the energy storage – an 
experiment is now done with a battery. A rechargeable battery can replace primary batteries and be 
used in nearly all portable electronic devices.  
 
Fig. 58: The Micro AAA and Mignon AA rechargeable battery types can easily be used for many 
portable electronic devices.  
 
Experimental set-up: solar module, patch panel, resistor, LED and also a rechargeable battery 
 

For the following experiments, you need a bright light source (or full, direct sunlight) for the solar 
module. 

 
The simplest possibility for charging is constant current charging. The battery is charged over a certain 
period with a defined current. With simple constant current charging of a battery, the usual practice is 
to charge it with 1/10

th

 the current of the capacity specification for 14 hours.  

 
With simple mains chargers, limitation of the charging current is achieved by a resistor which is 
inserted between the power supply unit and the battery. But with solar chargers this approach would 
be absurd. Here, the charging current can be achieved without loss by means of dimensioning (size) 
of the solar cells or the solar module. 
 
Thus not even a series resistor is needed with suitable dimensioning of the solar module. The solar 
module in the educational kit, which delivers a 35 mA current with full sunshine, can safely charge a 
battery cell. This proportionality changes with “larger” solar modules (producing more output) which 
can deliver more current. Then limitation of the charging current or a charging electronic device is 
urgently needed; otherwise, the battery would be destroyed. 
 
Fig. 59: Circuit diagram and experimental set-up of a simple solar charger; the diode was inserted so 
that the battery doesn’t discharge via the solar module at night.  
 
Fig. 60: Patch panel set-up: Charging current display with an LED 
 

20.  Step: Chemical processes with solar energy 

Experimental set-up: solar module, patch panel, dish, water, sodium bicarbonate or common salt, red 
LED, 4,700 µF electrolytic capacitor 
 

This experiment also works with little light (cloudy sky); the visible reaction in the water 
becomes clearer with full sunlight or a strong light source.