Lithium Polymer battery technology (with low internal resistance: typically 0.001 Ω) currently gives the highest Specific Energy (150–200 Wh/kg) of any type of rechargeable battery. 1 Given the design requirement to supply high current, 40–150 A (continuous) at low voltage DC (typically 7.4–22.2 V), the Li-Po is a natural choice (see Appendix A). Li-Po batteries typically range from 10 to 120 C.