Arduino alkaline-battery charger

An arduino project for charging non-rechargable battery

Disclaimer, or, use at your own risk

Charging non-rechargable battery is dangereous and must be done knowing the risks

Only charge battery that meet this requirements:

• Must an alkaline
• Residual voltage > 1.20V
• No damage or corrosion

Diagram

## Materials

This project require only components that are available on the Arduino Starter Kit.

• 1x Arduino Uno rev3
• 10x 220 Ohm resistor
• 1x Diode
• 1x Green LED
• 1x Red LED
• 1x TMP36 Temperature sensor
• 1x BC547 Transistor
• 1x Push button

How to use it

Steps:

• Reproduce the circuit on your breadboard (put the TMP36 in contact with the battery. If not possible you have to check manually the battery temperature)
• Paste the programm in the arduino IDE
• Download the Timer1 library
• Change the value of the constants if needed You are good to go.

Make sure to keep the battery well connected during the recharge process if you do not have a good mounting for the battery as it can leed to errors.

How it works

Current send to the battery

Non-rechargeable alkaline battery are rechargeable if the current is low enought and if they do not heat.

For that I am going to send a square periodic current throught the battery. The breaks allow the battery to cool down.

   <- 120 ms ->
5V ------------|  |------------|
               |  |            |
0V             |--|            |--
               <--> 5ms

Why use a transistor and not the output pin directly ?

Each digital pin of the arduino are capable of a maximum output of 40mA. That is not enought in our case.

TODO: Complete the explaination

Library

Arduino analogWrite() function don't allow to set the frequencies of the PWN. So to create a PWM with a frequency of 8Hz I use the Timer1 library.

References

TODO