Looking for a powerful brushless freewheel hub motor

[rmelendreras]

Hi everybody!

I'm trying to find a 48V rear hub motor, brushless and freewheel.

We are building a solar prototype over a bike structure. We decided to use 20 inches wheels (BMX). One of the three wheels is a Golden Motor Magic Pie hub motor, with 1kW/48V (www.goldenmotor.com). We have found a serious problem with it, the absence of freewheel.

Our intention is to participate in a energy-efficiency race (Solar Race Región de Murcia |) and the freewheel feature is necessary for us to improve our results. The prototype has a considerable weight, so we need a 1kW motor, because the minimum average speed in the race is 30 kmph.

Could you please recommend us a suitable motor or kit?

Thanks for your help.

Rafael

 

[onmebike]

Hi, I've made enquiry's with a contact in China and am waiting for an answer.
Should be later today or 1st thing tomorrow.

 

[drillam]

I got one from here :-

1000W 48V KIT Electric bicycle kit E-BIKE Motor Scooter 26'' - vpower

also batteries.

Looks very similar to these but cheaper:-

1000W 48V Alien Electric Bicycle e-Bike Conversion Kit on eBay (end time 30-Jul-10 23:12:51 BST)

My first electric bike so I can't compare it to anything else? all I'll say is that it takes my 92Kg weight effortlesly up the steepest of gradients and after covering around 300 miles or so it's given me no problems so far.

I got it from them on ebay, I think under £300 or so delivered.
slightly noisy but not obtrusive.

 

[Andrew harvey]

The Suzhou Bafang, BPM motor should do, it'll run happily on 48v, so will the Ezee motor. Most 36v motors will run to 48v with the right controller without to much concern, provided you limit the current down to about 20A.
I understand it's a race but why do you need 1kw. A true 1kw motor will need big batteries and drive you to around 30mph/50kph if your vehicle is a nice slippy shape.
The Golden motor unit is seriously old tech big, heavy and kind of crude.
I would suggest that if you want economy with power a lighter geared motor with a freewheel would be far better.
If you want to use solar panels,then for a 1kw motor your going to need around 10sqm of solar panels.
To get 30kph you should need only around 2/300w on an efficient bike.
This graph set is reasonably acurate,
Power Output
It depends on the terrain your covering as to wether or not you more power, then it might pay to get a fitter rider.

 

[rmelendreras]

Thanks everybody at the moment.

I'm jotting down your interesting comments.

The race is not a speed race, but a efficiency race. But one condition is that the average speed must be equal or higher than 30 kmph. Also, we must produce more energy than consumed.

I'm not sure if the 36V motor could give us the 30kmph speed. The prototype will weight 125kg (75 kg the prototype and 50kg the pilot).

Thanks again for you help.

I post you a link of the first video of the project:
UCAM Racing Team Channel on Vimeo

Rafael

 

[Andrew harvey]

A few questions.

Can you tell us more about the race rules or were we could find them? This should help us give better advice.
Will the rider be allowed to provide assistance to the motor?
If the ground your riding over is flat, a 36v hub motor would easily power you to over 30kph, on low current, I have built upright bikes that could exceed 45kph, with 36v motors and a 20A power supply. With the correct controller you can limit the current down, it cuts your acceleration a lot but leaves top speed almost unaffected.
The Golden motor you have tried is not the best even by the standards of direct drive motors and is to heavy. In my experience the 1kw claimed power rating for these motors is based more on the power they consume than the power they can output, at peak power they can be as little as 50% efficient.
Since you want a motor with free wheel I assume their might be some slopes involved.
In this case a chain drive motor, that drives through your gear system may be far more efficient. With this system you can use much smaller motors than you might expect, there are good examples with as little as 150w that provide enough power to assist a fit cyclist at the speeds you want, if the rider is allowed to pedal.

 

[rmelendreras]

Hello Andrey, thank for your interest.

I'm afraid that the rules are in Spanish, but they are very similar to the Eco Shell Marathon Race (well known in Europe).

My problem is that I have to solve the motor question in a month, because the race is the 1st of October, and I would like to do many tests.

Could you recommend me a suitable motor kit? I will order it assap.
Do we have to programme the controller?

Do you think that we will reduce the motor consuption? The maximum intensity that the Magic Pie motor yields is 12 Amperes (50 kmph).

Thanks again.

The links to the competition rules are:

European Rules Shell Eco-marathon 2010 - Global

http://www.murciasolarrace.com/repositorio/pdf/Normativa Solar Race 2010.pdf

 

[Jasper13]

google translation of spanish PDF in http://www.murciasolarrace.com/repos...ace%20201

This is zip file of a (not great) translation of the rules

 

[rmelendreras]

I've found a spanish e-bike provider with the following products.

Do you think they could serve us for the prototype?


References:

Motor delantero AT/BX Radiado 20”

The controller is a 36V controler with 8 wires (5 for HALL sensor and 3 for the phases)

Bienvenidos a CicloTEK Store - Controlador tipo B 36v

I listen to your comments ...

 

[onmebike]

This guy has quoted me $220 for 20in 48v 1000w rear wheel with freewheel inclusive of ems shipping[7-10days] Don't know if thats a good price or not.
You can contact him through ebay link below.

Rear48v1000w Bike Hub Conversion Kit Wilderness Bicycle - eBay (item 230493113089 end time Jul-28-10 02:46:35 PDT)

 

[dan]

Thanks everybody at the moment.

I'm jotting down your interesting comments.

The race is not a speed race, but a efficiency race. But one condition is that the average speed must be equal or higher than 30 kmph. Also, we must produce more energy than consumed.

I'm not sure if the 36V motor could give us the 30kmph speed. The prototype will weight 125kg (75 kg the prototype and 50kg the pilot).

Thanks again for you help.

I post you a link of the first video of the project:
UCAM Racing Team Channel on Vimeo

Rafael

I have a 48 volt 1500 watt electric scooter that we have used for spare parts, it has a number of body panels lights and batteries removed however the frame wiring motor wheels controller are all ok top speed is 30 mph, you are welcome to make an offer all of it or any parts.....send me a PM if interested

Dan

 

[rmelendreras]

Hello, Dan.

But, does your solution fit with the specs that I need?

I'm afraid that a 1500W motor has an elevated consumption that will oblige us to spend more surface for solar pannels. Also, the prototype needs 20" bicicle wheels, because we have bought special Michelin tyres in order to reduce the friction.

Thanks for the offer