Recently I build two wheels WiFi control Arduino Car which uses 4 cell 1.2V battery pack to power the car. The total voltage will be 4.8V. When I build the Bluetooth controlled Arduino car, I found that building a rechargeable charger on the car will be time saving because you don't have to take out the batteries every time and put them into a charger every time. So I thought I should build a lithium ion battery charger onto the new two wheel WiFi controlled Arduino car. I tested TP4056 - TC4056A Lithium Battery Charger and Protection Module which is described in Lithium Ion Battery and Charger and and used the 3S Li Ion Charger and protection module described in tutorial Lithium Ion Recharging Circuit in my autonomous Arduino robot car. I searched for a while and found that it is also possible to use LM317 adjustable voltage regulator IC. I already have some of LM317 IC so I could use these to build the charger. Below is picture of my completed LM317 based Lithium Ion batteries charger.
The corresponding LM317 Lithium Ion batteries circuit schematic is shown below.
You can watch the following video how I made this charger circuit.
I hope only that this recharging circuit works. Feel free to comment on working of this circuit.
