The battery is charged by AC plugging it into the wall, and the more you pedal the farther you can go. Your pedaling conserves the battery, but it doesn’t actually charge it.
The technology does exist that would allow you to charge your bike by pedaling, but we’ve found that it just doesn’t make sense in the real world.
So if your electric bike battery use a good one,most of time it is enough power for your ridding.
If you add a charging set ,the problem is that it makes it hard to pedal, and that’s not fun! Even under the most ideal conditions, like riding downhill, the amount of energy you would get back is negligible.