Features: Applied for any lithium battery with nominal voltage of 3.7V and full voltage of 4.2V (without limitation of shape or size). Suitable for the electric drill with starting current below 80A and power below 130W. Enables 100mA balanced current and 40A continuous current, gives well protection for the battery and ensures its longevity. 3pcs 15C~20C power batteries or 6pcs 10C~15C\'s are required to start the electric drill; and the 0V/12.6V connecting line that using copper wire over 13 square milimeter (do not use nickel sheet). Strictly follow the figure to connect 0V, 4.2V, 8.4V and 12.6V. Short circuit is prohibited. Resistance No. 430 may heat up when charging battery, which indicates that equalizer circuit is working; if resistance No. 430 heats up when not in charge, please check whether gets wrong wiring. Note: *Do not charge the battery of good quality together with that of bad quality. The better performance the closer the capacity/internal resistance of the 3 pack of batteries. The using effect of 2 good-quality batteries + 1 bad-quality battery is equal to the effect of 3 bad-quality batteries. *In the discharge test, the group of batteries with the faster voltage drop is the poor battery. *Do not connect wrong wires. *Please note that common 1-8-6-5-0 lithium battery can\'t power the drill on.