mission impossible for me -.-"

General Discussion about electric bicycles.
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piccio000   1 µW

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Posts: 1
Joined: Apr 23 2018 3:14pm

mission impossible for me -.-"

Post by piccio000 » Apr 23 2018 3:36pm

Hello.. :roll:
I'm new .. and I already inform you that I do not know much about electronics ...
so I ask you all help for my project ...

- bmx with wheels 20 "
- max speed: about 30 / 37mph
- average speed: about 25mph
- to use on level ground
- disc brake
- my weight 75kg
- battery life approximately 30km
- without pedal assistance

- budget ??? ... mmmm
the cheapest possible hahahahah

:roll: -> I have no idea which components to buy <- :roll:

(I'm sorry if it's not the right place for the post)

markz   100 GW

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Posts: 10150
Joined: Jan 09 2014 11:38pm
Location: Alberta Canada

Re: mission impossible for me -.-"

Post by markz » Apr 23 2018 6:47pm

A hub motor in a 20" wheel I do not know that would work because of the lacing pattern, but I am used to large motors. Maybe a smaller diameter motor would work.

Cheapest possible solution.
https://bmsbattery.com/ebike-kit/382-q1 ... e-kit.html

https://bmsbattery.com/ebike-kit/805-s- ... e-kit.html

https://bmsbattery.com/parts/612-thumb- ... results=70

https://bmsbattery.com/ebike-battery/81 ... ttery.html


https://www.leafmotor.com/hub-motor/20- ... n-kit.html

48V 12Ah -- 36V 15Ah Rack Li - Ion Battery Pack with BMS/Charger.

* BMS(BATTERY MANAGEMENT SYSTEM) and 100V~240VAC 50/60Hz 1.8A Universal Charger Included
* Weight: ~ 5.2Kgs
* Capacities: 48V/12Ah -- 36V/15Ah
* Max Discharge Current: 50A
* Max Continuous Discharge Current: 30A
* Charging Cycles: >2000 times
* Reference Ranges(full electric mode): 50Km
* Dimensions: 325mm L × 150 mm W × 84 mm H

Package Content:
1 x 48V 12ah or 36V 15ah rack lithium ion battery
1 x 48V or 36V 100V~240VAC 50/60Hz 1.8A charger
Net weight: 6.3Kg (with charger + slippery plate + discharging wire)

Package Size: 38cm L x 38cm W x 15cm H
Package Type: Cardboard Box
* LEV-High Speed 48V/12Ah $408USD / Set

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MadRhino   100 GW

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Joined: Sep 03 2010 5:28pm
Location: Montreal QC Canada

Re: mission impossible for me -.-"

Post by MadRhino » Apr 23 2018 10:05pm

The easy way is building with a geared hub, because it is small enough to lace easily in a 20’’ wheel. Not sure the top speed you can achieve though. Best place to find out, and have a good price is em3ev.com. Don’t buy before discussion, for they will need to know your top speed expectation.

Many DD hubs can easily do your top speed requirement, but it will be difficult to do a proper lacing job. DD hubs that are small enough won’t do it.

20’’ can also be found cast wheel DD. Not very expansive. Most will do your top speed.

Motorcycle rims are making it easy to lace a DD hub in that size, but there is a serious weight penalty. Rims are heavier, tires even worse. The closest size to a bicycle 20’’ is 14’’ motorcycle rim.
Make it fool-proof, and I will make a better fool.
Current bikes
Trek Session 10 mod. Variable geometry. 70mph
Santa Cruz V10. 50mph

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molybdenum   1 kW

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Joined: Feb 20 2014 11:09am
Location: Burnaby, BC, Canada

Re: mission impossible for me -.-"

Post by molybdenum » Apr 24 2018 2:45pm

What is the dropout width of your bike? Rear mounted hubmotor?
2012 Kona Dew Deluxe, Q128C and 9spd cassette, S12S sinewave controller, 48V Panasonic battery

torker   1 MW

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Location: Udall, Ks.

Re: mission impossible for me -.-"

Post by torker » Apr 24 2018 5:46pm

I radial laced a 9-Continent direct drive in 20 " wheel. So far it has held up well. I do not do many miles though.
Dave When I die I want to slide in sideways yelling WooHoo what a ride !

Giant Rincon w rear 9C 6*10 36 v x 20 amps
Specialized FSR Comp 9C 6*10 48v x 30 amps

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