Aprilia rs 125 conversion

[-larva]

Long time lurker here, I have been planning this project for many years but never found the cheap motor that would do what I want.

Bought this bike non-runing 6-7 years ago, I did get it to run after fixing some really odd things previous owner had done. Last week I finally took it from my dads barn to garage and strated removing ice parts.
Fairings are in pretty rough shape but everything is working. In this shape bike did weight little over 130kg on bathroom scale. I hope to stay under 150kg with electric version.
Bike has 30k km with very questionable service history, so engine isnt in best shape. Engine with carburator did weight 23,5 kg plus some other parts I removed ~10kg. I think there is about 10-15 kg more to lose but did run out of time and forgot to take any more pictures.

Plan is to instal qs 180 mid drive motor, probably with 2-stage reduction to avoid using extreme size sprockets. I have ordered the motor and it should ship in couple of weeks.
Went with far driver ND961800B controller and its on the way.
Im not sure about batteries yet, would like to use pouch cells to maybe make building a pack little bit easier.
Does anyone know anything about these.

https://a.aliexpress.com/_mLxsDDM

They do claim impressive c-rates and I need "only" about 600 battery amps.

Haven't been able to find many affordable bms's either that would took that kind of current.
Not sure if I try to register this, if so some kind of on board charger would be nice.

Goal is to have at least similar performance as with petrol engine and range of about 100km cruising 80km/h.
As mentioned I do this at my dads place and live in another city so progress is going to be slow. Let me know your thoughts and any advice is welcome!

 

[fechter]

That's an ambitious project. Any idea how heavy the stock bike is?

600A BMS units are hard to come by. A work-around for this is to use a small BMS to power a large contactor relay. The BMS only has to power the relay coil (most likely via DC-DC converter). If the BMS wants to trip, it will open the contacts.

 

[amberwolf]

Nowadays, there are off-the-shelf contactor-based BMS units so you don't have to DIY one. There's at least one thread around here with some; I think the ones pictured were by JBD?

 

[-larva]

That's an ambitious project. Any idea how heavy the stock bike is?

600A BMS units are hard to come by. A work-around for this is to use a small BMS to power a large contactor relay. The BMS only has to power the relay coil (most likely via DC-DC converter). If the BMS wants to trip, it will open the contacts.

Registration papers I have, say weight of 137kg and internet says anything between 129kg(dry) to 142kg(probably with full tank).
I have seen that done with bms and those ready made ones amberwolf mentions, both look little sketchy and was hoping to find something better. Ennoid bms (and its chinese copy) looks interesting but of course more expensive.

 

[-larva]

Haven't done anything with the bike since I last posted but some parts have arrived.
Chinese throttle and light switches, feels pretty good considering cheap price. Dc/dc converter is 30A model and should be isolated, it's big and heavy but should be plenty enough.
Controller packaging was not so great and it has some dents on corners of the aluminium bottom. Probably going to test it next weekend and see if it starts and connects to my phone. I don't have the motor yet but it should arrive in couple of weeks, I think.
Encoder version of the fardriver seems to have different wiring connectors than hall version. I did ask wiring diagram for this version but even that doesn't perfectly match with what I have.

Does anyone know name of these connectors? I tried google but couldn't find what they are actually called, it would make finding them locally much easier.

 

[larsb]

Kelly controller uses these, you can find some part numbers here:

 

[dominik h]

Starting the controller without the motor you will get an "lower mosfet bridge" error which disappears after restart with the motor connected.

 

[-larva]

Kelly controller uses these, you can find some part numbers here:
View attachment 332068

Thanks! I did find right connectors with those, mostly from aliexpress and other chinese sites though. Maybe I have to order them anyway.

Starting the controller without the motor you will get an "lower mosfet bridge" error which disappears after restart with the motor connected.

That is good to know, no need to panic if that error shows up.

 

[larsb]

I’ve had trouble with those connectors on the kellys due to the outer diameter of the wires being too small for the rubber grommet, letting water in.

You might want to check this on your connector, if it doesn’t have a good seal then i’d replace connector with something better, at least for throttle and hall sensor.

Deutsch DT connectors are nice and crimping tool is not so expensive.

 

[SlowCo]

Very interesting project. I'll follow your progress. Good luck and enjoy building it!