Some help for newbie - build an electric bike

Hi all, need some help from you. I already have an electric bike, but i don't know much technical details cause i bought it all made.

Now I want to build an electric bike. The main requirements:

1- Easily remove de motor, for this, I think front wheel is better, right?;

2- Light weight;

3- clean design, something like a non-electric bike.

The kit i'm looking at:

http://www.bmsbattery.com/controller/564-q75-front-driving-hub-motor-with-s06p-controller.html

http://www.bmsbattery.com/accessory/231-thumb-level-throttle.html

http://www.bmsbattery.com/ebike-parts/49-pas-pulse-padel-assistant-sensor.html

Do will I need anything more? Cables? Is there a smaller controller that works with Q75 motor?

About the battery, I'm planning to use 6S lipo, which is 22,2v, but the motor and controller are 36v, how does it works? Can I use 6S, will it works?

I also plan to but batteries and controller inside a case under the seat, any suggestions about the case?

Thanks!

How about 12s.

"36v" is 10s lipo. But many 36v controllers will run on 12s. Some won't.

There is no easily removable motor. For swapping between use as a motor bike and a light weight pedal bike, get two bikes. Put the motor on the cheap one, pedal the really good lightweight bike.

Planetary gear motors are the best for use as sometimes pedal sometimes motor bikes. Or the bafang bottom bracket drive type motors. Both will freewheel allowing normal use anytime. But you do still have to carry the weight.

Least expensive option, a small planetary gear motor on the rear wheel. Keeps the front feeling normal and light.

Get a complete kit, so you have all the wiring and display you need to make it all run. Some controllers may need only a throttle, some may need a display to function. Or perhaps just plugs may be different. Nothing to gain by piecing together stuff that may not plug and play

999zip999 said:

How about 12s.

Click to expand...

12s will increase the weight. Either, I have two 3s lips from my RC cars.

Will a 36v or 24v controller and motor work with 6S (22,2v)?

dogman said:

"36v" is 10s lipo. But many 36v controllers will run on 12s. Some won't.

There is no easily removable motor. For swapping between use as a motor bike and a light weight pedal bike, get two bikes. Put the motor on the cheap one, pedal the really good lightweight bike.

Planetary gear motors are the best for use as sometimes pedal sometimes motor bikes. Or the bafang bottom bracket drive type motors. Both will freewheel allowing normal use anytime. But you do still have to carry the weight.

Least expensive option, a small planetary gear motor on the rear wheel. Keeps the front feeling normal and light.

Get a complete kit, so you have all the wiring and display you need to make it all run. Some controllers may need only a throttle, some may need a display to function. Or perhaps just plugs may be different. Nothing to gain by piecing together stuff that may not plug and play

Click to expand...

Q75 is planetary, right?

What's is the kit with the smallest and lighter motor/controller? Do you have any suggestions? I'm not considering keyed, cause they take too long to delivery and are very expensive.

Thanks

The motor is suitable for a light-weight build, but obviously not quite as powerful as the Q100. It's a 201 rpm motor at 36v. A36v controller will switch off at anything below 31v; however, I believe that the S0SP will switch to 24v mode if the battery is lower, so should work at 6S. The 201 rpm motor would only run at 120 rpm which is about 10 mph in a 26" wheel. You could get the 328 rpm one, which would run at 210 rpm, but it would have virtually no power at only 6S. If you want realistic power, you need a 36v battery, which means 10S lipos. You'll get 20% more speed and power with 12S, which is the maximum that the controller can safely handle.

Perhaps if you tell us a bit more about what you're trying to achieve, we can advise you better.

You need to add a wheel-speed sensor to your shopping list for the speed display to work properly. It's probably a good idea to get one of their spoke keys too.

The small diameter motors are nearly all planetary geared types. Direct drive motors tend to be the size of a dinner plate.

Hard to suggest vendors or whatever without knowing where you live. I can't suggest the kits I sell here, nor do I know very much about other light motor kits.

I mostly wanted to point out that hub kits don't pop on and off the bike all that easy. You have to just pedal the weight of one around.

d8veh said:

The motor is suitable for a light-weight build, but obviously not quite as powerful as the Q100. It's a 201 rpm motor at 36v. A36v controller will switch off at anything below 31v; however, I believe that the S0SP will switch to 24v mode if the battery is lower, so should work at 6S. The 201 rpm motor would only run at 120 rpm which is about 10 mph in a 26" wheel. You could get the 328 rpm one, which would run at 210 rpm, but it would have virtually no power at only 6S. If you want realistic power, you need a 36v battery, which means 10S lipos. You'll get 20% more speed and power with 12S, which is the maximum that the controller can safely handle.

Perhaps if you tell us a bit more about what you're trying to achieve, we can advise you better.

You need to add a wheel-speed sensor to your shopping list for the speed display to work properly. It's probably a good idea to get one of their spoke keys too.

Click to expand...

Thanks for the explanation. I think now that 6s is not enought. The way is to get 10 ou 12S, even increasing the weight. The point now is that i think 10S Lipo will be as big and as heavy as my e-bike´s battery, so can´t see advantage in using lipos, as it doesn´t fit well in the bike. This is my battery (3,4 kg): http://www.yokuenergy.com/en/ProductShow1.aspx?ChannelID=3&TypeID=28&ProductID=175

thanks.

dogman said:

The small diameter motors are nearly all planetary geared types. Direct drive motors tend to be the size of a dinner plate.

Hard to suggest vendors or whatever without knowing where you live. I can't suggest the kits I sell here, nor do I know very much about other light motor kits.

I mostly wanted to point out that hub kits don't pop on and off the bike all that easy. You have to just pedal the weight of one around.

Click to expand...

I live in Brazil and here we do not have too much offer. Most Kit are poor quality, bikes too.

I founded a bike I considered good and bought it. It´s weight 24KG, and my ideia was to build something lighter and looking like a non-electric.

This is my bike, what do you think about it? http://www.generalwings.com.br/3toros.html

Thanks again.

You need to tell us your weight, how fast you want to go, how hard you want to pedal and something about the hills for us to give suitable advice.

d8veh said:

You need to tell us your weight, how fast you want to go, how hard you want to pedal and something about the hills for us to give suitable advice.

Click to expand...

Actually, there will be no hills, just flat. Top speed 25 km/h, as legal permission here. My weight 84kg. I want to pedal with less effort as possible.

Thanks

OK. then the 201 rpm Q75 should be fine at 36v.