12ah. About 300, 20ah. About 500, 24ah. Around 700. The price varies depending on the brand and length of time you use the plan. The best ones are Tianneng and Chaowei, which are the ones used by Xiaoniao and Xinri. The two brands have different battery models, so you need to match them.
Generally speaking.
The distance the battery can travel is not too far, {36V can travel up to 30 kilometers. 24 V only goes about 20 kilometers}. And battery replacement is expensive!
The selected motors are mainly brushless and have teeth that are noisy and the gears are easy to break!
In fact, lithium-ion electric vehicle technology is not yet very mature. It is recommended to wait one to two years before purchasing a lithium-ion electric vehicle!