What are the problems with e-bikes?

[ZhakirSetie]

Hey guys!

I'm currently working on a personal electric vehicle, with the purpose of solving some of the problems of modern urban cities transportation. Right now i'm focusing on identifying the market's needs and problems to better develop my product, and I wanted to ask you - what are the everyday problems and minor (or major) inconveniences that you have with your e-bikes (or electric scooters, if there are any here). I'm interested in anything you have in mind - storage, transportation, battery, safety, everything that comes up.

Thanks a lot!

 

[COAR]

COAR, I've seen one of those friction drives done probably about as well as can be done by that Keppler guy, but is there really any way that is suitable for off road? But since this thread is about ebikes in general, I guess application would dictate the suitability. Keppler's setup was pretty clean and minimal, but that kind of drive just sounds weird and antiquated to me. Don't take that as dissin' his effort there, but I guess I'm just a mid-drive guy.

He made a few videos of one being used for mt biking. Seemed usable in dry conditions. Impressive engineering that went into the whole thing but I lost interest when he had to take a belt sander to his rear tire to get the motor to bite.

 

[Grantmac]

Anything that negatively impacts traction and is fiddly to setup isn't going to fly in the commercial realm.

Personally I see the integration of gearboxes and motors in the frame as the big leap for EMTBs. Electric motors need lots of reduction but not lots of gears, humans can turn pretty high gears but over a very limited RPM range.

 

[TrotterBob]

If you could figure out a way to use the heat generated by the motor to recharge the battery, that would be cool.

Theres always Seebeck modules. But would it really be worth it to enclose your motor in a metal shell then line the outside with several modules and put heat sinks all over those modules? Then theres the issue of converting that varying DC voltage to something useable and feeding it back into the battery.

Sounds like quite a bit of expense for little yield. I'd look into regenerative braking and maybe a small solar panel over a front bike basket before going down the rabbit hole of turning heat back into electricity.

Also higher voltages and lower amps for the same amount of watts is generally more efficient as less power is lost in the form of heat. So the question then becomes how high of a DC voltage are you comfortable with? I'm sticking with 60v or less since I'm still a rookie and the thought of my frame going live and shocking myself while riding is not an appealing one. Also working on less than 60vdc battery packs is safer and theres less chance of serious injury. Touching 52vdc typically does not deliver a shock thru dry adult human skin because the resistance is too high to allow current to flow.

 

[HK12K]

If you could figure out a way to use the heat generated by the motor to recharge the battery, that would be cool.

Theres always Seebeck modules. But would it really be worth it to enclose your motor in a metal shell then line the outside with several modules and put heat sinks all over those modules? Then theres the issue of converting that varying DC voltage to something useable and feeding it back into the battery.

Sounds like quite a bit of expense for little yield. I'd look into regenerative braking and maybe a small solar panel over a front bike basket before going down the rabbit hole of turning heat back into electricity.

Also higher voltages and lower amps for the same amount of watts is generally more efficient as less power is lost in the form of heat. So the question then becomes how high of a DC voltage are you comfortable with? I'm sticking with 60v or less since I'm still a rookie and the thought of my frame going live and shocking myself while riding is not an appealing one. Also working on less than 60vdc battery packs is safer and theres less chance of serious injury. Touching 52vdc typically does not deliver a shock thru dry adult human skin because the resistance is too high to allow current to flow.

I never said it was practical, lol. But if science can find a way to convert that energy....

 

[TrotterBob]

I never said it was practical, lol. But if science can find a way to convert that energy....

I didnt mean for my comment to sound condescending. Apologies if it came off that way.

 

[HK12K]

I never said it was practical, lol. But if science can find a way to convert that energy....

I didnt mean for my comment to sound condescending. Apologies if it came off that way.

Not at all. My comment was largely tongue in cheek to begin with.

 

[jimmyhackers]

most ebikes look lame.

make the bike from akira.....

then you can take all my money.

 

[TrotterBob]

most ebikes look lame.

make the bike from akira.....

then you can take all my money.

Why wait? I saw a company that makes carbon fiber bike frames in custom configurations. Time waits for no man.

 

[TrotterBob]

If you could figure out a way to use the heat generated by the motor to recharge the battery, that would be cool.

Maybe we're closer than we think.

https://news.northwestern.edu/stories/2021/07/new-material-thermoelectric-performance/