1991 Suzuki Rm125 build

[Akimpobeditel]

Hello, here is a picture of the bike when I brought it home, we named it Ronald.

I stripped the paint off everything and primered the frame. Overall bike is in a pretty good condition, especially for being 30 years old. It needed new swing arm bearings and new rear wheel bearings, but other than that everything was in a pretty good shape.

I haven't ordered the motor yet but I decided to use qs138v3. I 3d printed it to start figuring out how to mount it and where to put other components.
So far I have the motor mounts designed and 3d printed. I should be getting laser cut metal for the motor mounts later this week.

For the battery I plan on using as many Molicel p42a cells as I can fit. hopefully I can squeeze 21s10p battery pack in it somewhere.

Controller will be Votol em200.

Next step is to cad the frame or laser scan it so I can design a battery pack for it.

 

[EVOXY6768]

Will be following your conversion. Can I asked which version of the EM-200 Controller you are going to be using ?

 

[Akimpobeditel]

Will be following your conversion. Can I asked which version of the EM-200 Controller you are going to be using ?

Thanks! I think its em200/2. I know some of the em200 had some issues but the sales guy reassured me that they sell em200/2 now and its been updated/fixed.

 

[rider119]

Mind sharing the CAD file for the QS138 V3?

 

[Akimpobeditel]

Mind sharing the CAD file for the QS138 V3?

Sure thing.
https://drive.google.com/drive/folders/1O2tqn4maLCXHy40fuzVh1QCnmRNjlrTN?usp=sharing

 

[rider119]

Mind sharing the CAD file for the QS138 V3?

Sure thing.
https://drive.google.com/drive/folders/1O2tqn4maLCXHy40fuzVh1QCnmRNjlrTN?usp=sharing

Thank you sir!

 

[spinningmagnets]

Thanks for posting the details of the build, plus the pics!

 

[Akimpobeditel]

A little update.

I got the motor mounts from laser cutting and of course I ordered everything but one part!! I also printed a jig to tack weld it and make sure that its dimensionally accurate. I still need to pick up 20mm steel bar and cut it and drill it for the motor mounts.

Motor and controller should be here next week. Later this week I should get windows kinect 2 and try to 3d scan the frame. Then I'll start designing the battery box.

I am contemplating whether I should run molicel p42a or run something like this https://www.aliexpress.com/item/4000349081372.html?spm=a2g0o.cart.0.0.6ea33c00RDRN1g&mp=1

It will be a lot easier and cheaper to run polymer li-lion cells and 130A continuous and 225A peak should be plenty at 75.6V nominal(or not?)
It will be much easier to make a battery pack out of those compared to individual molicel cells.
Any advice with the battery? I am very open to suggestions and advice!

 

[Akimpobeditel]

Alright, I got the motor and the controller. It was shipped on Monday and I got it Friday, from China to Florida in 5 days is quite impressive, gotta love DHL!
My motor mounts work which is good news. I have also decided on the battery. Its going to be 21s 60Ah with 150A continuous and 300A peak and built in bms. Size of the battery is going to be 170*250*265mm at approximately 20kg. 1150USD shipped with 10A charger included.

I had to trim the frame a little bit to fit the battery. It seems like its going to be quite wide but it actually measures roughly 10 in wide and the tank should cover it almost completely if cut the inside of it. My friends wr250 is actually about 11 in wide in the narrowest point so I think is should be just fine with that size. I am also quite excited to be able to get quite a bit of run time out of a battery that size, as I do plan to make it street legal and ride it round on the road.

 

[EVOXY6768]

Your build is progressing really well. Do you have a link for your battery ? BTW thats one good thing when you order from QS,there delivery time is great and they send a vid of everything running before sending.

 

[SlowCo]

Nice build :thumb:

 

[Akimpobeditel]

Your build is progressing really well. Do you have a link for your battery ? BTW thats one good thing when you order from QS,there delivery time is great and they send a vid of everything running before sending.

Thank you! I dont have a link for the 60Ah battery as I was talking to seler on aliexpress and he said that he can make me custom one. Unfortunately, I found some information online that he isn't very trustworthy and uses used/damaged cells sometimes. Its too much time and money to test my luck with those batteries. I was talking to Shenzhen Foxelion batteires Company Store representative.

Now I am pretty set on using cells like those. https://www.aliexpress.com/item/4000349081372.html?spm=a2g0o.cart.0.0.29b63c00uyh0CI&mp=1

I am currently trying to talk to manufacturers on alibaba and buy directly from them and not from a reseller on aliexpress. I have a 300A smart ant bms coming in the mail already, as I was planing on making my own battery from the very beginning.

 

[Akimpobeditel]

I put the bike together a little bit last night. The frame is primed right now, I am planning on painting it blue after I finalize everything and ride the bike for the first time. I want to put the controller where the radiator used to be, I am working on the bracket for it right now.

In case anyone needs a pretty accurate model of votol EM-200/2, I drew it up - https://drive.google.com/drive/folders/1-C-XJ7-DOhsfZXNged6M6hjhJq6QMiso?usp=sharing

 

[Akimpobeditel]

I designed the mount and printed a 3rd(to save material and time) of the controller mount today. It fits well but I need to have to plastics on to finalize the design. I ordered the plastics but it won't be here for another week or so. I can also save .7 kg if I go with aluminum of the same thickness compared to steel, so I am debating whether I should start learning how to tig aluminum with my new tig welder

Here are some pictures of the controller and how it fits on the bike. Its a very simple design but added complexity and laser cut time makes it more expensive and I am trying to stay under $3000 for this build Mounting plate also utilizes all stock mounting locations.

 

[Elektrosherpa]

This is a good position for the controller-at least from the cooling point of view.

As for the holder:
Maybe you are thinking too complicated and perfectionistic?
I would build it without welding, just screwing together aluminium angle profiles and flat material.
(During my build I have become a fan of using aluminium, due to light weight and easy processing,
and me too, I am not (yet?) able to weld aluminium)

 

[tylerwatts]

I'd say go with Aluminium, and weld it up yourself. TIG is so user friendly if you have a steady hand, just don't bury the tip in the weld pool and use good gas. Once you've practiced a few times you'll never want to not weld stuff up yourself. Regardless of the material also.

And nice thing with TIG is no setup to change materials you're welding, just change the power and grab different filler wire. I wish I had my own TIG setup at home.

Great looking build also. Have you considered building your own battery by just buying cells from the manufacturer and using 3d printed housings designed by N.E.S.E. cad files are free and you can print your own stuff already, just need the tabs kits and you get fantastic cell d entity and totally modular and easy to maintain if a cell dies.or you want to reconfigure etc.

cheers
Tyler

 

[Akimpobeditel]

This is a good position for the controller-at least from the cooling point of view.

As for the holder:
Maybe you are thinking too complicated and perfectionistic?
I would build it without welding, just screwing together aluminium angle profiles and flat material.
(During my build I have become a fan of using aluminium, due to light weight and easy processing,
and me too, I am not (yet?) able to weld aluminium)

I think so too, plus it looks cool!

I tend to do so, I am trying to have everything perfect, while I probably shouldn't, especially on my first electric build.
Well I have a tig, so might as well learn how to weld!

 

[Akimpobeditel]

I'd say go with Aluminium, and weld it up yourself. TIG is so user friendly if you have a steady hand, just don't bury the tip in the weld pool and use good gas. Once you've practiced a few times you'll never want to not weld stuff up yourself. Regardless of the material also.

And nice thing with TIG is no setup to change materials you're welding, just change the power and grab different filler wire. I wish I had my own TIG setup at home.

Great looking build also. Have you considered building your own battery by just buying cells from the manufacturer and using 3d printed housings designed by N.E.S.E. cad files are free and you can print your own stuff already, just need the tabs kits and you get fantastic cell d entity and totally modular and easy to maintain if a cell dies.or you want to reconfigure etc.

cheers
Tyler

I think I will. I know how to mig, so I am familiar with welding already. I just need some practice time with the tig now.

Thank you!
At this point I think I will have to build my own battery. I was thinking about using Molicel p42a but dealing with 200+ individual cells is not something I'd like to do frankly. I also looked into catl prismatic cells that Silent Enduro uses. Extremely easy to make a battery out of those but they are a bit heavier and don't seem to have good discharge rates. 1c continuous and maybe 2c peak?
I am looking into lithium pouch sells right now. It seems like it's my best option so far. Good energy density, high(3c cont 5c peak) discharge rates and I only need to solder 21 of them. I am talking to a couple of manufacturers on alibaba right now, and it looks like I will be able to find something in 39-52Ah range that will fit my frame. Like I said I have a 300A ant bms coming in the mail already too.

 

[Elektrosherpa]

. ...1c continuous and maybe 2c peak?
.... I am talking to a couple of manufacturers on alibaba right now, and it looks like I will be able to find something in 39-52Ah

The Alibaba manufacturer,
where I ordered (but not yet received) my battery (72V 54 Ah)
offered me 3 c continuous and 5 c peak.

If this is true will turn out when I will finally receive it.

In general, buying directly from China takes a lot of time and patience.
I started my build end of winter, and right now it looks like I wont get ready for a first drive before late autumn.

 

[Akimpobeditel]

. ...1c continuous and maybe 2c peak?
.... I am talking to a couple of manufacturers on alibaba right now, and it looks like I will be able to find something in 39-52Ah

The Alibaba manufacturer,
where I ordered (but not yet received) my battery (72V 54 Ah)
offered me 3 c continuous and 5 c peak.

If this is true will turn out when I will finally receive it.

In general, buying directly from China takes a lot of time and patience.
I started my build end of winter, and right now it looks like I wont get ready for a first drive before late autumn.

Did you order a complete battery? Would you mind sharing the specs? like size, weight?

Yes, it is very tiring! I can only communicate with them couple of hours per day and they are pretty bad at organizing information on their websites/pages.
I hope to finish mine before the end of the year but I am not sure if that is possible.

 

[Akimpobeditel]

Finally found a suitable battery for my build! 42Ah cell 3.7V nominal, 3C continuous and 5C peak(10 seconds), 720g/cell, 173x188x10.8mm.
According to the seller its an SK brand battery and a quick search shows that they provide batteries for Ford, VW and Hyundai. How much of that is true I obviously don't know but energy to volume ratio made sense compared to the other batteries out there. Price was right too, $490 for 21 cells including shipping and fees. Seems too good at $17.8 per cell, we'll see how good they really are. I would be very interested in buying another set of cells to make a second battery for it down the road.

At 42Ah hopefully my build will be very similar to a KTM freeride in terms of capability and riding time, which is all I want to be honest. It would be my first trail bike and I am planning on learning how to ride trails on this thing. My 1200gsa doesn't do so well in Florida sand haha

 

[Elektrosherpa]

Did you order a complete battery? Would you mind sharing the specs? like size, weight?

Yes,
I mentioned it in another build thread:
https://endless-sphere.com/forums/viewtopic.php?f=12&t=113263&p=1674979&hilit=battery#p1674979

But I want to emphasize that by no means I want to promote this manufacturer/seller.
I havent even received the battery, and the order process was more than exhausting...