My electric bicycle can run for 80 minutes at 55 km/h or more at no load. But if you load it, you can run only 4-5 km at more than 20 km/h. However, when the load is removed, it runs again at 55 km/h or more. The battery is 36V 7.5Ah and the motor is 250W. The specification of the controller is also attached.
Could you tell us what caused the problem?
Overcoming air resistance and rolling resistance during running requires much greater power. A battery 7.5Ah 36 volts is not a sufficient source of power (energy is 270 watts). However, I was expecting a little more. My battery is 48V/20Ah (960 watt energy) and can run 30 miles (50 km) at a higher speed of 21 miles per hour (35 km/h). Your battery is literally a 1/4 energy amount of my battery. But the mileage is only about 1/10 of 5 km for my 50 km. This number seems to be very low.
The running time is estimated to be about 15 minutes (5 km/20 km/h). With 270 watt battery and 250 watt motor, you can expect longer uptime (about 1 hour). This suggests that your battery may not be rated. It seems to have reached only about 25% of the rating. Or your bike may have some other staggering loss or resistance.
What exactly do you mean by “without any load”?
It probably refers to the state where the wheel is away from the ground and the bicycle is traveling without load.
If this is what he intends, this difference is quite reasonable. An explanation is required for a very short range of 270Wh.
In short, he has obtained only about a quarter of the mileage to be obtained. The “floating distance from the ground” of the wheel is not an appropriate indicator. However, the mileage to be obtained while driving a bicycle should be 4 to 5 kilometers or more. It should be about four times the distance.
Unless he is a very heavy rider, it is likely that the battery does not meet the rated performance unless he is towing the trailer or living in a very undulating area.
weight or resistance?
not running on the ground
In short, he has obtained only about a quarter of the mileage to be obtained. The “floating distance from the ground” of the wheel is not an appropriate indicator. However, the mileage to be obtained while driving a bicycle should be 4 to 5 kilometers or more. It should be about four times the distance.
Unless he is a very heavy rider, it is likely that the battery does not meet the rated performance unless he is towing the trailer or living in a very undulating area.
Overcoming air resistance and rolling resistance during running requires much greater power. A battery 7.5Ah 36 volts is not a sufficient source of power (energy is 270 watts). However, I was expecting a little more. My battery is 48V/20Ah (960 watt energy) and can run 30 miles (50 km) at a higher speed of 21 miles per hour (35 km/h). Your battery is literally a 1/4 energy amount of my battery. But the mileage is only about 1/10 of 5 km for my 50 km. This number seems to be very low.
The running time is estimated to be about 15 minutes (5 km/20 km/h). With 270 watt battery and 250 watt motor, you can expect longer uptime (about 1 hour). This suggests that your battery may not be rated. It seems to have reached only about 25% of the rating. Or your bike may have some other staggering loss or resistance.