Solar Universe India Lithium Ion (Li-Ion) Battery of 3.7V-2200mAh with inbuilt BMS, suitable for 4V Solar Applications, This is a single unit of 3.7V-2.2ah (2200mAh) Lithium Ion Battery with inbuilt Battery Management System (BMS) which provides it multiple protections as well as ensures enhanced battery performance & life. This type of battery is suitable as a retrofit or replacement for traditional 4V lead acid type batteries used for powering 4V Solar Lanterns, Kits, LED Lanterns and for experiments & science projects. One may use it like any other battery but with the advantage of having a lithium-type battery that is portable, durable, easier to install & handle as well as more efficient. It can be charged via 6V solar panels of 5W & above with a suitable charge controller in between. By purchasing a charge controller or regulators, one can use it for off-grid purposes while trekking, camping or otherwise. If used efficiently & properly, it will deliver up to 1000 cycles during its lifetime. We recommend Solar Universe India Solar Panels & Charge Controllers for the best performance of this battery.