LiTech Power is designing and producing Battery BMS / PCM / PCB / CMB with BesTech Power, Battery Management System is the core part of one battery pack, it protects lithium batteries from overcharging, over-discharging, over-current, over-temperature..., so it is the "heart" of one battery pack. therefore never use lithium battery packs without BMS/PCM/PCB. If you can not find a suitable BMS / PCM / PCB on our site, please call us or email us.