Important technical parameters of electric bicycle

The electric bicycle is a more popular means of transportation in the city, and plays a very important role in environmental protection, and is also the preferred tool for young people to travel.

1, "range" claim
Electric bicycle range is defined as follows: "When the new battery is fully charged, the rider weight configuration to 75 kg on a flat secondary road (no strong wind conditions) ride, ride until the battery voltage is less than 10.5V / section to be disconnected, in the above conditions, the ride sex mileage is known as the electric bicycle range"
electric bicycle
Generally with 36 volts 12 amp hours of quality batteries of each brand-name electric bicycle range is about 45 ~ 60 kilometers, and there are individual manufacturers of the nominal will rise to 70 ~ 80 kilometers, which has the suspicion of false propaganda. This is because this nominal value means that the efficiency of the motor is nearly 40% higher than the efficiency of the motor used by the brand-name factory. If a brand-name factory produces the motor in the above description of the working state of the efficiency of 75%, the motor efficiency of the manufacturer of the nominal 70 ~ 80 km has reached more than 100%, which is obviously impossible, which is especially to remind consumers of.

In actual use, how many kilometers can be driven with sufficient power in the end? This is related to many factors, and the manufacturer has a segment of the factors are mainly the efficiency characteristics of the motor, battery capacity and life characteristics; and other objective circumstances related to the factors: the weight of the rider, often ride the road conditions, whether the need to use the brake often, how the cyclist's cycling habits, etc.. Another issue that needs to be frequently reminded to consumers is that the battery capacity will gradually become smaller with the growth of use time, and the distance that can be driven with sufficient power will also be reduced. When the maximum driving distance of the old battery cannot meet the traffic needs of a day, you can consider sending the battery for repair or replacing it with a new one.
electric bicycle
2、Maximum motor output power and maximum output torque.
The maximum output power of the motor is a key indicator of the torque capacity of the electric bicycle wheel. Generally, each electric bicycle factory will set a maximum working current according to its own technical level, and when the external load is large, the working current of the electric bicycle reaches the maximum, and the output power also reaches the maximum. For example, if the maximum working current of an e-bike is set to 12A and the working voltage is 36V, the maximum input power reaches 432W, and if the maximum current of an e-bike is limited to 15A and the voltage is also 36V, the maximum input power reaches 540W. Obviously, some motors maintain high efficiency at high currents, while some motors severely lose efficiency at high currents. Most of the electric bicycle motors in 430W input efficiency has been reduced to about 55%, the maximum output power is 430 × 0.55 = 236W, the maximum output torque is only 14N.m. Obviously, a maximum torque of 25N.m electric bicycle and a maximum torque of 14N.m electric bicycle in the climbing ability, allow the load capacity and resistance to wind resistance, etc. There is a big difference in many aspects, and the feeling of riding is completely different. If the consumer needs to test the maximum output torque of the vehicle when purchasing, the easiest way is to "climb with weight".
electric bicycle
3, motor rated output power and output power range.
Motor rated power is an important parameter for motor driving test, it means that when the motor works in this power point, the motor can run continuously and reliably, characterizing the thermal balance point of the motor design. Generally the rated power point of electric bicycle motor can be 150W, 180W or 200W or more, the higher the rated point means the better the thermal performance of the motor and the higher the cost.

Since it is impossible for an electric bicycle to work in an unloaded state, the weight of a normal cyclist will generally reach more than 30 kg, and considering normal wind resistance and other factors, the minimum working point (output power) of an electric bicycle is about 80W, and the maximum output power depends on the design scheme of the motor. The output power of the better electric bikes available in the market can generally reach 200W or more, while the individual motors are less than 200W. The larger the output power range, the better the riding performance.
electric bicycle
4、Electric bicycle efficiency and efficiency interval
E-bike efficiency is a combination of electric hub efficiency, control system efficiency and mechanical rotation loss, but mainly depends on the efficiency of the electric hub (motor), which can reflect the same battery, the same riding load conditions riding mileage, high efficiency is long riding mileage, low efficiency is vice versa, for users, the purchase of higher efficiency to reach the electric bike is undoubtedly the right.
electric bicycle
However, the efficiency of electric bicycle also needs to have a range, because the motor efficiency is different under different torque, expressed as a form of saddle curve, some electric bicycle motor at low power is more efficient, once the output torque increases, the efficiency value drops sharply, this kind of car is often shown as a flat road speed is very fast, once the uphill speed drops sharply, the power consumption level will also increase significantly.

The concept of efficiency interval to replace the concept of pure rated efficiency is an important feature of electric bicycle, because the vehicle load is a very variable load, its working point will be with the vehicle load state, road slope, driving wind resistance of different and great changes, the pursuit of a high efficiency of a working point and ignore the efficiency characteristics of the whole working area is meaningless.

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