All battery packs are based on standard Li 18650 cells and come with a UN transport test (UN 38.3) as standard. Lithium-ion batteries are the energy source of the future. With approximately twice the energy density of NiMH cells and very low self-discharge, this technology is the optimal energy source for all kinds of applications. Li-ion battery packs are thermally stable and highly resistant to cold. The integrated protection circuitry safeguards against overcharging, overload, short circuits, and deep discharge.