It is bottom 2 pins connection. The size is 39cm11cm7.5cm(Length x width x hight), please make sure this size can be installed to your bike. If you need to discharge cable connect to bike controller power cable, please mind the the red wire is positive +, the black wire is negative. Battery Type:Fish Lithium-ion. Rated Voltage / capacity: 48V / 15Ah. Case Material: ABS+Aluminium alloy. Batteries combinations:13-S, 6-P. Component:Li(NiCoMn)O2. Recommend to use: 250W-1000W. Time :Standard 0.2C5A×5hrs; Quick 0.5C5A×2hrs. Installation position:Inside on the PCB. Certification: CE, RoHS, MSDS. PCB board Protection:Over charge, over discharge, over load and short circuit. BMS board Protection:BMS is used to supervise battery by measure its voltage, temperature, current and SOC (State Of Charge), give out alarm under wrong circumstance, cut off electric power link in severe situation in order to protect battery and make its life longer. BMS can balance energy among batteries to make them more identical and expand its discharge cycle.