LIR 2032 rechargeable coin battery is small in size, can be used in mini Arduino projects and a good replacement for my TV remote
In this instructable, I am going to share how I made a charger using TP4056. And I will explain how to limit charging current for any single cell Lithium ion rechargeable batteries
Step 1: What Do You Need ?
- Battery holder
- 100K SMD register that i extracted from a old faulty mobile charger
- Magnifying glass
- Soldering iron
Step 2: Concept
As per the TP4056 datasheet, if we alter the value of Rprog the charging current changes. Now based on the battery specs, I needed to set constant charging current to 17mA,
So the Rprog value is about 100K Ohm to to get approx 13 to 15mA, Formula in the Datasheet
Step 3: Modify
- By Default the TP4056 modules have Rprog as 1K Ohm.
- I needed to replace it with a 100K Ohm. WHich I extracted from old fault mobile charger
- I used regular soldering iron to remove the existing SMD register
- While replacing it with 100K, it was quite difficult.
- Do not overheat the PCB
- Once the register is soldered, check the voltage drops across Register etc
Step 4: Batter Holder
- Fix the battery holder directly on the charging module
- Test charging the LIR2032
Please note that the charging LED s do not glow as the current is reduced below operating current. We can still note the voltage drop across them
Please share your comment, if you try this or have ideas to be make it better