diy li-ion capacity tester ! - li ion battery cell
When it comes to building battery packs, Li-
There is no doubt that ionic cells are one of the best choices.
But if you get them from the old laptop battery, then you might want to do a capacity test before building the battery pack.
So today I'm going to show you how to make a Li-
Ion capacity tester using Arduino.
Let's start!
You can watch my video if you don't want to watch everything! 1)PCB (
I ordered it online but you can use zero PCB)-
Power resistance-10k Resistor-OLED -Arduino-Buzzer-
Screw Terminal-
Female Headers-
N-channel Mosfet-
We must know what capacity is.
The unit of capacity is mAh or Ah.
If you look at any Lee-
Ion batteries, they will mention its capacity above, just like the 2600 mAh mentioned above.
Basically, this means that if we connect a load on it that draws 2.
The battery can then last for an hour.
Again, if I have a 1000 Battery and the load consumes 2A, then it will last for 30 minutes, which is what Ah or mAh means.
But it is actually impossible to calculate in this way because we all know V = IR.
Initially our battery voltage was 4.
If we keep the resistance constant, some current will flow through the load.
But over time, the battery voltage will decrease and our current will decrease.
This will make our calculations much more difficult than expected, as we need to measure the current and time of each instance.
It's actually impossible to do all the calculations now, so here we will use Arduino to measure the current time and voltage, process the information, and finally give us the capacity. Note!
I have an SPI OLED so convert it to I2C and use it.
If you would like to learn how to convert SPI to OLED, please see my previous tutorial-
If you would like to make changes to the PCB and schematic, is this a link to my project? The Arduino first measures the pressure drop generated by a 10 ohm resistor (if above 4.
3 v, it will turn off the MOSFET to display high voltage if less than 2.
9 v it will show the low voltage, it will turn off the MOSFET if it is between 4. 3v and 2.
9 v it will turn on the MOSFET and the battery will start to discharge through the resistor and measure the current using Ohm's law.
It also uses the millis function to measure the time and product of current and time, which gives us the capacity.
Then I started the welding process on the pcb I ordered online.
I would recommend using the female title as if you would like to remove OLED or Arduino in another project later.
After welding, when I connect the power supply, sometimes it doesn't work as expected.
Maybe because I forgot to add the pull-up resistor on the I2C bus interface, I went back to the code and used the built-in Arduinos-
Pull up the resistor.
After that it worked perfectly!
If you like my job, feel free to check out my YouTube channel for more highlights: also follow me on Facebook, Twitter etc for upcoming JLCPCB $10pcs,10*10cm)