How to choose electric bicycle power supply?

Some electric vehicle batteries have a short lifespan, which can cause problems in less than a year. The reasons for the short battery life, in addition to the battery's own reasons such as low purity of lead (some use recycled lead), process formula, plate technology and processing accuracy, etc., the following reasons also directly affect the battery life.
1. Charger: The two-stage charger has simple circuit and low price, which is easy to cause voltage instability. Overshoot, floating, and no protection directly affect battery life.
2. Controller: low price, incomplete function, excessive discharge current, no overload, undervoltage, current limiting protection, causing over-discharge damage to the battery, which may potentially affect the battery life.
3. Motor: low-speed, brushless motor, heavy motor, large iron loss, copper loss, magnetic steel demagnetization, low efficiency, no clutch, poor sliding function, immediately increase resistance without power, high current consumption, high current discharge drive. In the same situation, it consumes more power than a brushed high-speed motor and has a shorter running mileage, which affects battery life.
4. Most scooters are equipped with low-speed, brushless motors, the weight of the bike, riding without assistance, resulting in short battery life.
The working characteristics of the battery used in the electric bicycle are: small discharge current, long power consumption time, deep discharge depth, and cannot be charged while driving. For example, if the motor power is 139W and the starting current is 15-25A (amperes), the working current of the motor will decrease with the increase of vehicle speed. After reaching 18km/h (kilometers/hour), the current will be about 7A (amperes). The longer the driving distance, the deeper the depth of discharge, such as driving 30-40km per day, the depth of discharge will reach about 60%-80%. Therefore, the power supply for electric bicycles should use deep charge and discharge power batteries.
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