Left: Master-LV, Middle :  slave board LTC6811, Right: Master-HV I received several requests upon how to use ENNOID-BMS for monitoring lithium-ion battery packs. I will present here the basics and how to use ENNOID master & slave boards when building a custom battery pack. Lithium ion basics The purpose of a BMS is quite simple to understand once you know the basics of lithium-ion battery cells, their limitations and the danger of using them inappropriately. Lithium-ion cells are mainly used because they have one major advantage over all the other type of batteries available on the market : they can store more energy for a given space & weight. Despite this main advantage, they have many issues when not properly used. They tend to overheat and loose their capacity when discharged too fast. Their cycle life can get destroyed when their internal temperature gets above 60 degrees Celsius. They have performance issues when discharged with temperature below 0 Celsius and t