# Yamaha Majesty 250 conversion



## frodus (Apr 12, 2008)

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.


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## Johnny J (Nov 27, 2008)

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


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## Johnny J (Nov 27, 2008)

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...


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## RIPPERTON (Jan 26, 2010)

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.


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## Johnny J (Nov 27, 2008)

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:


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## Johnny J (Nov 27, 2008)

Could look something like this:


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## tylerwatts (Feb 9, 2012)

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?


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## Johnny J (Nov 27, 2008)

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. ;-)


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## RIPPERTON (Jan 26, 2010)

+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 .


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## tylerwatts (Feb 9, 2012)

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.


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## Johnny J (Nov 27, 2008)

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


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## 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!


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## Johnny J (Nov 27, 2008)

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


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## Johnny J (Nov 27, 2008)

Well the rear swing sits perfectly:








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


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## Johnny J (Nov 27, 2008)

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.


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## Johnny J (Nov 27, 2008)

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

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


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## Johnny J (Nov 27, 2008)

Jigsaw puzzle with adjustable parts...


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## Johnny J (Nov 27, 2008)

Finished and painted:


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## Johnny J (Nov 27, 2008)

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


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## Johnny J (Nov 27, 2008)

Preparing the batteries..


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## Johnny J (Nov 27, 2008)

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.


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## Johnny J (Nov 27, 2008)

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


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## Johnny J (Nov 27, 2008)

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.


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## Johnny J (Nov 27, 2008)

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.


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## Johnny J (Nov 27, 2008)

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.


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## darkmunk (Dec 15, 2015)

This looks great.
Newbie question: How do you run/charge the bike electrics?
I may have missed it, but which batteries did you use?


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## Johnny J (Nov 27, 2008)

I have a 300W DC/DC converter for all the 12V stuff, also a small aux. 12V NiMh battery since I didn't want to run a 100V through the key switch.
Battery brand is CHL, have the same in my other scooter, really good quality, can handle 6C without too much voltage drop.


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## darkmunk (Dec 15, 2015)

Thanks. I look forward to more updates


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## Johnny J (Nov 27, 2008)

First test drive!

Wow, the power! Will do 130km/h easily, Went up to 120 on the really short drive.
But, the motor does not like the 34kW forced into it, will need to limit the Amps, the motor cables got quite hot.
Also got a couple of Hall sensor readout faults meaning I had to turn the ignition off and back on again. Will check this later.


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## Johnny J (Nov 27, 2008)

Finished!


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## RIPPERTON (Jan 26, 2010)

Nice work, lets see a video.
Next thing you will do is try to find ways of cooling the motor.


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## Johnny J (Nov 27, 2008)

First thing I need to do is to get it approved by the proper authorities, might take some time..

I'll post a video soon, just need to figure out how get rid of those hall sensor misses that causes the Sevcon to cut the power, might be angle faults that causes it.

I have turned the power down to 20kW, I don't really need so much on this scooter, but if you have any good suggestions they are welcome.


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## RIPPERTON (Jan 26, 2010)

Johnny J said:


> First thing I need to do is to get it approved by the proper authorities, might take some time..
> 
> I'll post a video soon, just need to figure out how get rid of those hall sensor misses that causes the Sevcon to cut the power, might be angle faults that causes it.
> 
> I have turned the power down to 20kW, I don't really need so much on this scooter, but if you have any good suggestions they are welcome.


Sounds like wiring faults maybe in the plug.
Hall sensors are easy to replace and you might be able to get Sevcon compatible ones.


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## Johnny J (Nov 27, 2008)

The motor is quite new so there shouldn't be any problems, but as you say it might be a connector problem. 
This motor has an extra set of halls so I can try them out.

The thing is, it's only sometimes when I do fast accelerations that I get the cut outs and it could be software related. There are quite many settings in the Sevcon software...

Actually I had the exact same problem on my E-rider Thunder scooter also with a Sevcon but a different brand of hub motor, but not as frequent, only once in a while so I didn't really care about it.


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## Johnny J (Nov 27, 2008)

Did a longer run the other day, went up to 130km/h quite quick, didn't dare going any faster in the traffic, but there still is some power left.


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## tylerwatts (Feb 9, 2012)

Sounds very good Johnny. When can we see a vid?


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## Johnny J (Nov 27, 2008)

Yes! All approved and ready for the road!


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## Johnny J (Nov 27, 2008)

My 1500W TC Charger broke a few weeks ago just after the bike got approved, only lasted like 3 charges so the bike has not been ridden at all since then.
I could have sent it to them for repair, but 2 freight costs is very expensive so I ordered a new one instead.

Received it last Friday and put it in over the weekend.
I got their new model which is 1800W, about a 1/3 of the size and weight and a bit cheaper as well.
Charges with 16A, so 3 hours is enough for a full charge.

Went out for a 40km ride today and it took almost exactly 1 hour to charge it back to full with the new charger.
This is very encouraging since this would give me a range of more than 120km with an average speed of around 60-70km/h.


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## electro wrks (Mar 5, 2012)

That is a very compact charger. Who makes it and what's the model?


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## Johnny J (Nov 27, 2008)

This is also a TC Charger, www.tccharger.com
Model: 1.8KW HK-H Series On Board Battery Charger

Observe that normally this is CANBUS controlled, but they made a special version for me that is "Enable-Disable" controlled, i.e. 2 wires.
Good price, $259 +freight, taxes etc.


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## tylerwatts (Feb 9, 2012)

Hey Johnny, any vids yet of performance and finished setup please?


Tyler


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## Johnny J (Nov 27, 2008)

Unfortunately I haven't had the time to solve the problem with the cutouts yet, so I have to accelerate quite slowly and this doesn't make a video very exciting.
Will try to put my helmet cam on next week anyways.


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## jaheen100 (Mar 1, 2017)

WOW It looks so cute and reliable.


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