DIY Lithium Battery Case Dayi 21V Li-ion Power Tools with 18650 holder and Balance-Protection Board (10004885)

Looking to take your DIY projects to the next level? Say goodbye to traditional power sources and hello to the future with a 21V Lithium Battery Case! This innovative power solution is equipped with an 18650 holder and Balance-Protection Board, ensuring your tools stay charged and protected during use. Let's dive in and explore the endless possibilities this DIY battery case has to offer!

It can fill 15 pieces of 18650 Li-ion power batteries. But this is plastic shell, there is no battery inside.

Preparation before assembly: (1). If a new core is used, please note: a. 18650 power lithium battery core must be selected, b. A group of 5/15 cores must be equipped with resistance and capacitance to make their voltage the same (Must be balanced before assembly). (2). If the old battery is repaired, please test the voltage at both ends of each cell. If the voltage is different, please charge each cell to the same voltage value. Very important: