ebike 250watt project

[doctor_t]

Hi Guys,

I'm not very new of this forum and i follow you for long time.

i built up my frist ebike almost 4 years ago and since that time i built other 10 ebike with different motor hub sistem and battery teconology

now i m going to start a project of a new ebike and i need some of your advice if you can help me

ebike caracteristics

bike for everyday ride, street way and not off road with carbon frame 29'' for mtb
hub motor rear wheel 250watt to be legal in europe with pedal assistance of different level and no throttle

for battery i would prefer Lipo but Lion bottle is more easy to charge and to take care

i m thinking to have parameters telemetry like speedict sistem to check battery status and all the rest

i have an idea of almost all components that i need to use but i would like your advice regarding different fields

1. what will be the best motor of just 250, that is light and also with a good torque that is not to stressed while climbing
2. possibility to use lipo or lion battery with regen brake sistem
3. alterative to speedict app for telemetry

i hope to have some of your precious adivices

 

[dogman dan]

Lithium lipo, lico, limn, any of the lithium types can do regen. But batteries with bms's may not, or may have limited regen abilities. So ask your battery retailer about their stuff. It just varies.

Rc lipo (lico), comes without a bms, so none of those problems there.

Re the motor, the ones with the slower RPM specification will get up the hills better ( less overheating) than the high rpm ones.

The motor catch 22, the small, light, low power motors with planetary gears inside can't do regen at all. You would have to lock the internal clutch on one of those to get regen. The internal freewheel allows easy pedaling with the motor off. That can extend range better than regen anyway.

 

[doctor_t]

thank you dogman

i also think that regen is not a great idea and bettere use a motor that allow you to have no resistance while pedaling without motor

so i had a look at keyde motor and also tdcm
http://www.tdcm-motor.com/

they look nice and seems to me good but don't have any experience and i need to try

what about alternative to speedict and some good lightweight motor?

 

[dogman dan]

I just don't have the experience with the smaller motors to say. My long ride up a long hill in the desert led me to dd motors with more power I'll move this thread now to ebikes general, and maybe you will get more readers.

 

[d8veh]

thank you dogman

i also think that regen is not a great idea and bettere use a motor that allow you to have no resistance while pedaling without motor

so i had a look at keyde motor and also tdcm
http://www.tdcm-motor.com/

they look nice and seems to me good but don't have any experience and i need to try

what about alternative to speedict and some good lightweight motor?

The TCM is not yet available as a kit. The bit that goes in the bottom bracket is a non-standard size, so you can't fit it to a bike. I spoke with them about it at the Shanghai show last week. They told me that they have a standard size one under development. The 8Fun crank-drive kit is standard, and it's very similar. You can find it on Aliexpress. Both these crank-drives are fairly smooth and quiet, and they have about the same power. Hill-climbing in low gears is good but quite slow. A 250w hub-motor has more power in the mid-range.

I tested a bike with the TMC motor for more than a week. I went round my usual hilly routes, and managed to get up all the steep hills without puffing and without having to stand on the pedals. Battery consumption wasn't much better than my 500w hub-motor at the same speeds because I was using high power nearly all the time. The main downside with these crank-drives is that they make your gear-changing a bit crunchy because the motor runs on a bit after you stop pedalling, which keeps tension on the chain while you change gears. I tried one with a Nuvinci, which is a perfect solution. Don't even think about Shimano Alfine or Nexus hub-gears. It won't work.

At the show, Bafang had a more powerful version of their crank-drive. They said it was 750w, but had about the same power as my 350w GNG Gen 2 at 22 amps. Theirs had a 48v battery and I suspect 15 amps. It was much quieter than the GNG and it had an enclosed reduction system like the TMC. They also told me that the motor was a little wider and had thicker wire than the 250w version.

 

[doctor_t]

for the last 4 years i made myself many electric bike with different kind of motor, 1000W, 700W, and 250W.

for sure is much more funny to ride on 1000W, 15 cells Lipo or maybe 20 and get 60 km/m maximum speed
but the problem is that this motor without power is not very easy to push

that's why i want to use a geared 250 W hubmotor and also pedaling without power is not that strong

im also in touch with Keyde motor company and i think they are making a good product but should test it
what can be the price for a nuvinci hub motor?

 

[dogman dan]

Yes, to pedal without power, you want the gearmotors. I just didn't like what happens with the small ones when you get a strong headwind. I just built a bike intended to ride with a typical output of 100w. It's perfect for riding alongside my dog, at 5 mph. But if I get a steep hill or a headwind, I still have 1200w avalialbe.

The secret to this bike is the very slow motor winding. Look for that low rpm specification, when you want to build a small light bike that can still get up a hill.

 

[chisixer6]

I would vote for the cutie 100 type with the lower rpm, lightweight, great for commute and riding on the street, cheap 24v 250watt, but I use 48v to umph it a little, mine is the higher rpm and uses 16" wheels.

 

[doctor_t]

Yes Guys, it's great i think that we always know that 250W is variant for riding flat and without wind

with my 250watt i can ride easily almost 50 km at 25km/h average speed without wind and in flat ways but in case in need to climb or with lot of wind this power is not enought

I always want to consider that a bike should always be a Bike and not a MotorBike that's why my option is for 250watt
I asked Bartimeus to help me with amperometer for telemetry and by now i'm waitng for components to start first experiments!!!

by the end of the month Keyde will send me their motor Kit for rear wheel 250 Watt and try this new motor

 

[doctor_t]

I think they should be enough for my 250watt hub motor

 

[doctor_t]

here there is some of my works

http://flybike.altervista.org/

i will appriciate adivices and comments

 

[AlexG]

Did you receive your keyde motor and have you tested it yet, if so what is your experience with it? I have a Kit in order from them as well.
Alex

 

[chas58]

Nice work!

You know that a small 250watt hub motor that is designed for hill climbing will have a pretty low top speed right?

What speed and distance are you looking for?

Most of those lithium ion bottle batteries are 0.8 to 1.0C, which means they cannot supply much current to your motor.

I think you have figured out that if you want to be able to pedal the bike, you don’t want regen – you need something that can freewheel when not under power.