Honda C50 conversion

[supercub50]

Hi everyone,
so I bit the bullet and actually decided to start on this project to convert my Vietnemese '76 Honda C50 to electric hub drive (in the fashion of the Shanghai Customs build).
Many thanks to "Flo" with his Sachs project, for providing me help and information on what the German authorities will be looking into, once it's all ready for the streets. Really got me motivated.

I've now stripped the bike and found a replacement swingarm from a '71 CB 125 K with 200 mm rear hub width, which I need to be able to fit the QS 205 with a drum brake (standard swingarm allows for max. 175-180 mm so it's a no-go).

IMG_20190605_070149.jpg

Yesterday my motor arrived along with the SVMC72150 controller. I got to say that the service from QS is amazing (thanks Damon!) and I am very happy with quality.
It's a 3kW V3 50H unit with kv 13 with 110 mm drum brake, which with 60V supply hopefully will provide for comfortable 60 km/h cruising.

IMG_20190605_070110.jpg

And it fits! Just need to open up the ends and get some axle adapters with 12 mm flats machined and welded on.

IMG_20190605_070122.jpg

The controller will be going inside the frame where the tank used to be, maybe mounted upside-down under the cover plate. There won't be much space though, so I might need a while to plan on how to fit everything neatly inside. For the battery, I am planning for 40 Ah capacity to get decent range, which due to its size then means that it's going to go where the original motor used to be. Some sort of mechanically-solid battery casing will be necessary.

My 2 yo daughter keeps me busy as well, so bear with me if updates will not be that often. But I am excited! Once it's an actual "rolling chassis" I will be starting on the battery and electrics.

[flo]

Hi
will be very intresting how you get all into there.

Good luck

Flo

[3DRoboGuy]

Hi Supercub50,
Good luck with the project.
Like Flo says, it'll be interesting to see how you shoehorn everything into the available space (doesn't look like you have a lot of it)
Have you selected your batteries yet, 60V but, home-made 18650 cells or... ?
Super interesting to see how it all pans out. Keep the posts coming.
Robo

[supercub50]

Thanks for the interest! Sorry I was away on vacation for two weeks so nothing new on the project I am afraid.

For the battery, I was thinking of using NCR20700B cells, 10 pcs in parallel and then 16 groups in series. Have them positioned vertically, basically two packs in 10P8S configuration in series, one pack on top of the other. Should have quite compact dimensions and therefore fit relatively easily.

QS recommends max 6 kW peak power for the 205 motor so my battery current will be less than 150 A at all times, which that cell type should manage easily I think.

I have access to a 3D printer so definitely I would like to design and print my own cell holders. For the BMS I was thinking of the Energus tinyBMS.

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[supercub50]

Can somebody tell me, does the Sabvoton controller get hot in operation? The max. battery current going to it will be about 100A.

Originally I was thinking of hiding the controller inside the frame, but in that case it would not be receiving much moving air for cooling.
Another option I was thinking about is to manufacture brackets for suspending the controller on the main tube of the frame, so it would be outside instead.

[supercub50]

Finally an update! Sorry, still just mechanical things...

Got the swingarm mounted. Still need to offset it a little bit, and consider fitting an additional tube inside the original swingarm spindle tube, as the spindle has got some play (and is not sitting absolute straight - damn this build quality). Some project I've gotten myself into, the paper thin frame has some rusty holes to fill as well.

Also the shocks I got are too short.

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[supercub50]

Hello again,
sorry about not posting any updates on this since a very long time.

After discovering the QS 120 70H mid motor, I decided to abandon the hub motor idea. I got everything mounted but really didn't like the feel of the rolling bike with the heavy ass rear. So I sold the 205 and the Sabvoton, and got the 2000w midmotor and Nucular 6F instead.

I designed and had laser cut mounting plates made, which also double as fixing point for the original footpegs.

Now I've been researching different ideas for the battery. If in front of the motor, with more room but needing more crafting of sturdy mounts, or still inside the monocoque frame but obviously limited in size.

It looks that I will be making a 10P14S 18650 pack, which would yield 50,4V and 35Ah. With a Bluetooth BMS and removable, so that I can charge it inside of those e-bike charging station cabinets.

To be continued soon I hope!

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[Richard230]

Nice job!

[supercub50]

Got the controller and the cable throttle mounted on a mock-up plate, and found an old 48V battery for testing. The throttle cable is a bit short still, hah.

But it works! Very happy now, finally some dynamic on this project. Though I have no experience with other controllers, but still I must say the Nucular is amazing. Very easy to set-up even for a beginner like me.

My BMS, cell holders, DC-DC arrived this week, and I found un-used but cheap INR18650-35E cells for my actual battery. So that's what's coming up next

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