Expectations for battery and motor life span


Well-known member
Local time
3:39 PM
Jul 5, 2022
This will be a difficult question to answer as there are so many ebikes on the market of varying quality.

Having said that, what do you think are a reasonable number of miles (in terms of total life, not per trip) to expect to get out of battery and motor on an ebike of decent quality (subjective, I know). Assume the bike is well cared for and not ridden in rain or stored in harsh elements.
It's all about choosing the correct motor for your needs, and then installing it and using it correctly, with awareness of it's capabilities and limitations. Many motors are available in multiple windings, or turn counts, or speed versions, so as to be tuned to a specific use case. Same motor, same model, some as many as 5 different ratings, almost always at least two. It is a torque vs speed choice.

Geared motors often have different internal gearing as well as the turn count change, for DD hubs it is exclusively the number of turns of copper wire around the stator that makes the difference.

My motor is approaching 30,000 miles. If I had chosen the hi-speed version, of the same motor, it would be long dead by now. Since this would do nearly 30mph in a 700c wheel, I might be dead by now. That motor would have needed me to not engage the throttle until well over 10mph pedal only, and would not handle hills or headwinds well at all. If, however, you are a competitive cyclist at a high level, it would have made an excellent training cycle, which is where I got the idea.

The lowest-speed version would have had decent takeoff ability, and handle hills and headwinds better, but likely not do much over 16mph and likely would have been upgraded. Would not have required me to pedal assist much at all.

The medium-speed version, which I choose, does 20mph in the 700c wheel, takes small hills and stiff headwinds just fine with some pedal assist, and is fine engaging throttle at 2-3 mph. With the throttle, I never NEED to pedal but it is advisable at various times, and I have the gearing to provide more speed and more acceleration as needed, or just to extend my range to maintain a comfort zone. Most ebikes are not geared for anything much over 15 mph human pedaling speed. That's why I started with a road bike.

I do not ride off-road at all. Smooth pavement. I weigh less than 200 lbs, do not carry large additional loads, and have no significant hills to deal with. So I could trade torque for speed, and the smooth roads means no need for heavy shocks and suspension and can use thin, narrow tires with road tread, which contribute to less need for torque and the choice for more speed, all for roughly 15 lbs of added weight so I can easily lift the bike when needed. All with over 30 miles easy range, and a bike I could pedal-only for 30 more, if necessary.

Same motor, same voltage, was either 210 rpm, 260 rpm, or 328 rpm.

Most folks here do not even know what a Kv rating is, and have no clue about choosing the right version for their needs. They think more watts means more speed.

On batteries, both my $900 original battery and my $200 replacement battery both lasted about 5 years. Both had FAR more than the minimum recommended amp-hour capacity. GET MORE AMPS.