Cylindrical Lipo Batteries (12v)

[Richard Hill]

Hi,
New member here - I am stunned to find a group who are into doing this. I think this is the future of bikes personally.

I've got a 12v motor that I want to run inside the seat tube - but I want a battery that will sit in the seat tube also.

Does anyone know a supplier of cylindrical batteries?

regards

Rich

 

[FurryOnTheInside]

I think most batteries are cylindrical lol. 18650 batteries should do it, pretty obvious that it will only give a boost for a few moments. Google "mechanical doping in cycling" as this has been done before, as a form of sports fraud.
I hope this is not your purpose!

 

[Frankenstein]

Well, the 12v motor, it's kind of small in voltage, how exactly is this going to be used? Did it come from something that generated a decent level of torque?

Also what size tube do you have, you can get lipo batteries in all range of sizes, with a custom board and enough room you can put a series of 3 batteries along the interior of the tube, and if it is big enough you could stack a couple in parallel within the tube, you could get a sizable chunk of wattage in it if you wanted that would give a helpful boost up something like a hill on a work route or wherever.

The voltage is still kind of an issue. I think some treadmills use a 12v motor but those are a little large for this, 12v has a hard time making a very strong motor unless it's big or just has a largish transmission stuck to it (like in a drill for example, small motor and a transmission 3 times larger than the motor to make usable torque.)

I'm curious as to what you are trying to experiment with, please share.

 

[Richard Hill]

Hi and thanks for the replies on this thread. I am trying to power a bike nice and aesthetically pleasing by putting the motor in the seat tube along with the battery. I want to then have a small arduino like device that will work off a blue tooth button on the handle bar that will engage the motor when I want.

The way I imagine this happening is that the motor will point vertically down and will have one half of the bevel gear attached. This bevel gear will be mounted horizontally.

The other half will be on the bottom bracket shaft - mounted vertically.

The part I am having a hard time working out is how the bevel gear will engage and turn the bottom bracket - BUT - disengage when not being requested.... my friend mentioned a clutch gear but I am not so sure....When I get time I will put up a diagram to more explain what I am trying to achieve.

 

[Frankenstein]

Hi and thanks for the replies on this thread. I am trying to power a bike nice and aesthetically pleasing by putting the motor in the seat tube along with the battery. I want to then have a small arduino like device that will work off a blue tooth button on the handle bar that will engage the motor when I want.

The way I imagine this happening is that the motor will point vertically down and will have one half of the bevel gear attached. This bevel gear will be mounted horizontally.

The other half will be on the bottom bracket shaft - mounted vertically.

The part I am having a hard time working out is how the bevel gear will engage and turn the bottom bracket - BUT - disengage when not being requested.... my friend mentioned a clutch gear but I am not so sure....When I get time I will put up a diagram to more explain what I am trying to achieve.

You still haven't provided info into as what you plan to use as a motor.. You are comming against a certain hurdle where the power outputed by the motor needs to be geared up to give good torque, if your bracket doesn't have enough room for a large enough gear then you won't be able to reduce the rpm enough to make it useful.

For example, a 10k motor reduced even as much as 25 to 1 is spinning at 400 rpm, which is more than twice and probably 3 times faster than you could pedal at at the crank. If you had a 2 inch bottom bracket and somehow squeezed a 2 inch gear in there and reduced the output to 25 to one you would have to have a 2mm wide gear on the end of the motor. Obviously this wouldn't be physically possible if you expected it to drive any load since that's just how it is.

You should be more clear about what you are working at or with, if the motor isn't a hundred percent appropriate for this (like both strong and at low enough rpm to be workable like this) then it won't do any good untill you over engineer the transmission (which also has to be strong enough to stand up to the forces needed to drive a bicycle and person forward.)

 

[Richard Hill]

The motor I've got is an EtonM PGM22a -: http://www.etonm.com/products_dt/productId=56.html

I'm doing this as a hobby idea so please excuse me if I am not quoting what you want to see. I do appreciate any input though.

What I would like to do is create something that would give 'some' assistance. I am not looking for it to take over the job of pedalling just some assistance.

 

[KCvale]

The motor I've got is an EtonM PGM22a -: http://www.etonm.com/products_dt/productId=56.html

I'm doing this as a hobby idea so please excuse me if I am not quoting what you want to see. I do appreciate any input though.

What I would like to do is create something that would give 'some' assistance. I am not looking for it to take over the job of pedalling just some assistance.

That would be cool on a wheel chair, I am working on that very thing for my son and I.
As for a motorized bike, that electric curtain opener/closer motor is a really poor choice for an e-bike.

 

[Richard Hill]

That would be cool on a wheel chair, I am working on that very thing for my son and I.
As for a motorized bike, that electric curtain opener/closer motor is a really poor choice for an e-bike.

Curtain raiser ! Lol - i guess it is in a way. I don't need much power for what I want to achieve I just want to 'notice' that I am being assisted a little bit. The majority of a cyclists power tends to be in getting up to speed. Once up to speed on a flat surface doing approx 30mph you need about 300 watts (I am discarding all sorts of drag , wind, terrain,. tyres here).

If you think that motor is a poor choice - how about you suggest one???

 

[FurryOnTheInside]

Picture from the Cycling News article Mechanical Doping, A Brief History (everything you need to know about mechanical doping)
http://www.cyclingnews.com/features/mechanical-doping-a-brief-history/

Picture of a Vivax-Assist motor from the cyclist.co.uk article Motor doping is happening and we've tested it
http://www.cyclist.co.uk/news/542/motor-doping-is-happening-and-weve-tested-it

 

[Frankenstein]

If you think that motor is a poor choice - how about you suggest one???

That last line is genius, he's just quoting a point on the diagram, speaking of which this motor is less than an inch in diameter, and with the optional gearbox at a stage in reduction that could be useful to your needed rpm at the crank it will generate so little power you should not be able to feel it unless you are picking the bike up off the ground to use the motor.

https://www.vivax-assist.com/en/product/vivax-assist/vivax-assist_4-0.php
This is essentially what you are trying to create, a hidden motor that powers your bike a bit. Notice this is 200 watts, that's decent for something 31mm in diameter, but it's also something you could actually feel, I'd say probably something like 50 watts could be felt but only minorly. This is also something around 24 volts by the maths, which is a decent step up from 12.

I would suggest a motor if I had a clear idea where to look for something suitable, electric motors are just a world of needs and ability to be made cheaply enough, so something perfect might not even exist, often these things are built to demand, not like engines that are endlessly copied (but similarly you'd be hard pressed to find certain arrangements in specific sizes or formats, especially as they get more complex.)

What size seat tube do you have, that would be a place to start before anything since that's our limit, what is the inner diameter of the bottom bracket as that will affect motor rpm due to limits in availability of gear sizes? A one way clutch is cheap and easy to acquire, and can be small enough for something like this.