Yamaha Majesty 250 conversion

Johnny J · Mar 13, 2014

I have been riding electric 2-wheelers since 1992, converted 2 cars, already own an electric motorcycle scooter, but this will be my first motorcycle conversion.

I had a new Quanshun 100V 8kW (nominal) hub motor laying around so I thought I had to do something with it.

Other parts I will be using is:
30pcs (96V) CHL 50Ah Li-batteries.
Sevcon Gen4 Size4 max 350A controller.
Mini-BMS
DC/DC 300W
TCcharger 1500W

It will be some weeks before I get all the parts but I will soon start with the 2 most difficult things, the first is to remove the engine and weld brackets for the new rear swingarm. Secondly I have to find space for all the batteries and weld together a box for them.

frodus · Mar 13, 2014

Nice!

Make sure the encoder type on the BLDC Hubmotor is correct for the Sevcon Gen4 Size4. You'll need the IXXAT programmer to set it up and likely spend a good amount of time trying to get it properly tuned.

Johnny J · Mar 13, 2014

Yes I already have an IXXAT and a good file for this motor.

Johnny J · Oct 18, 2014

Well, finally I've got the time to start for real. Taken the scooter apart and it seems it should be possible to find space for the batteries, battery boxes and the other stuff. Also located a nice place for the Sevcon controller where the old cooler used to be.
Removing the old motor will add lots of room.
An advantange with hub motors...

RIPPERTON · Oct 18, 2014

Johnny J said:
First is to remove the engine and weld brackets for the new rear swingarm. Secondly I have to find space for all the batteries and weld together a box for them.

These 2 should be done simultaneously.
Design the new swingarm and brackets to accommodate the battery pack.
You might have to place cells beside the swingarm where the muffler was for example then the swingarm bracket would be narrow and reaching far forward, the swingarm itself could be very long reaching forward to where the riders feet are.

Johnny J · Oct 18, 2014

Thanks for your input.
I already hava a swingarm that's made for this hubmotor, it is quite long so the rear battery box can stretch over it close to tire.
I´ll mount the tire on the motor next, put it around where it should be and start measuring for the mounts.

Motor out:

Frame without:

Johnny J · Oct 19, 2014

Could look something like this:

tylerwatts · Oct 19, 2014

Johnny that looks great. And you should fit alot of batteries in there. What performance are you expecting though? Is the 8kw nominal? Could you add some cooling and push the voltage for a bit more power? Or is it a city runaround you are building?

Johnny J · Oct 19, 2014

Well I have bought 30 cells and will start with that. The top speed will be around 110-120km/h.
I have a similar motor on ny other scooter and I can push that up to 13kW momentarily without a problem.
The controller can supply up to 34kW, so it¨s all up to my nerves how I will limit it. ;-)

RIPPERTON · Oct 20, 2014

+1 that does look great Johnny you will fit a truck load of cells in there.
I think that motor has the same core as I used on my Mira, will do 30kW easy. Open it up for some air though .

tylerwatts · Oct 20, 2014

Johnny it is worth giving Ripperton a look inside the motor to confirm how similar it is. If you can improve cooling and run even up to 20kw bursts for say 30s that will be a huge step in performance. I'm very interested in your build as I commute by motorcycle and would love an evbike.

Johnny J · Oct 21, 2014

I´ll think about that, maybe Ripperton has some advice how to improve cooling without taking it apart?

Scottydog · Nov 4, 2014

Hi Johnny,

So I bounced myself to this forum to see your current scooter project. I should be able to gain some knowledge on potential options for my project by following your ideas and layout... if that is cool as I want to have fairly high performance also.

Look forward to following your build!

Johnny J · Nov 13, 2014

Fixed the brackets for the new swing arm, not so pretty but strong:

Johnny J · Nov 15, 2014

Well the rear swing sits perfectly:

And the new shocks fits as well. Now it's a roller!

Johnny J · Nov 22, 2014

After rearranging the cells it seems I'm lucky, all the 30 cells can fit at the "lower level" where I wanted them, not much room to spare.

Johnny J · Oct 26, 2015

After several months with a bad back I'm back on track.

The frames for the front and rear battery boxes are ready.

Johnny J · Oct 30, 2015

Jigsaw puzzle with adjustable parts...

Johnny J · Nov 10, 2015

Finished and painted:

Johnny J · Nov 19, 2015

Finished welding brackets, starting to test mount different stuff.
This is fun!

Johnny J · Nov 26, 2015

Preparing the batteries..

Johnny J · Nov 30, 2015

Batteries are in! Really really tight fit, had to shoehorn them in.

Found this Russian made 32-pole connector on Ebay, perfect for measuring and topping up individual cells.

Johnny J · Dec 4, 2015

Working with all the wires and connectors, a video before everything is connected and tidied up.
https://youtu.be/OyU7r4hSVSw

Johnny J · Dec 15, 2015

Today I did the first complete test of all the electronics, No magic smoke anywhere!
BMS, DC/DC, instruments, lights and everything else seems fine.
Motor is also running, but I'm having some issues with the controller.
I have e-mail Sevcon, hopefully they can help me out.

-No luck there, have to buy 1000 controllers to qualify for support....seriously...
Will be some trial and error, luckily I have a few different files to test.

Johnny J · Jan 6, 2016

Yes!

Finally got the Sevcon right.
Now the main contactor closes and the controller goes in to drive mode when I turn the ignition key.

Also fixed the side stand switch and the reverse, activated by a switch beside the throttle.

Johnny J · Jan 12, 2016

Have started putting it together.
I will repaint the main plastic covers later, but no hurry, quite a few weeks until the weather permits riding.

Yamaha Majesty 250 conversion

Top Contributors this Month

Recommended Communities