Ni Cd Battery Charger

The nickel-cadmium battery is a popular type of rechargeable battery for portable electronics and toys using the metals nickel (Ni) and cadmium (Cd) as the active chemicals. They are sometimes used as a replacement for primary cells, such as heavy duty or alkaline, being available in many of the same sizes. It is commonly used in Mobile Phones, Rechargeable Torch, model airplanes etc.


Picture of Battery Charger Project
In our project we have used 2AA size Ni-Cd Battery which is commonly available and can be used in many appliances. This circuit can also recharge common dry cell battery for fewer times at certain level.

Nickel-cadmium cells have potential of 1.2 V. So Nickel-cadmium batteries come in multiple of 1.2 V for eg 2.4V, 3.6V, 4.8V etc but it maintains constant voltage throughout their service life and about 0.8–1 V when discharged.

The chemical reaction which occurs in a NiCd battery is:

2 NiO(OH) + Cd + 2 H2O ↔ 2 Ni(OH)2 + Cd(OH)2

 Here is a simple and slow charger for better life of small Ni-Cd battery. Charge it for 6-12 hrs using this circuit.

Part List:
 
Step Down Transformer 0-6 V
Mains Cord
Diode 4007
Resistance 10 Ω X2 Pcs
LED
Battery Container