1Note:Successful starting of the drill requires two 10C-20C power batteries, or four 5C-10C power batteries (Recommended power battery models: (VTC4, VTC4A, VTC5A, VTC6) 0V and 8.4V connecting wires, using copper wires of 2 square mm or more (no nickel chips!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!) . 2 Precautions:The first time you weld the battery needs to be charged before output;. Strictly according to the diagram wiring 0V, 4.2V, 8.4V, welding line can not touch any components on the board, do not intentionally short circuit. 3 Note: The first welding battery or charging, as long as a single battery more than 4.2V, ‘430' resistor will heat up to discharge (discharge to 4.19V or so to stop heating). If the ‘430' resistor is seriously hot (too hot to touch), please check if it is connected to the wrong wire.