Welcome, I’m back with a new interesting project, today I will make a 4.20 volt (li-ion 18650 battery, mobile battery) battery management device, using this device you can check actual battery capacity, you can adjust discharging current while testing battery capacity, you can charge the battery with a live monitoring system in the display also you can adjust battery charging current, you can prepare a battery for long term storage for long battery life and more features.. this device very useful for everyone because nowadays everyone uses Li-ion battery, and now widely available this lithium-ion with fake capacity written on battery, to check the battery is fake or original you need this device, so for those who want to do this project, first watch my video tutorial for better understanding and after watching the video you can download code from here and complete your project. You can find the circuit diagram, component list, code below