Rieju 50cc conversion

[eee291]

Sorry to hear that, I've never had any issues on the 12 other packs I used.
Maybe it degraded unevenly from the sun heating one side


BTW what BMS are you using?

[larsb]

I tried it a bit at 400A, could’ve been too much with 13C. That 10th cell was always weaker though, since i run the ANT 300A smart bms with display i can see the voltage values every time i ride.

I’ll just fix it, no worries.

[eee291]

Just wanted to make sure if the BMS didn't skip on the B- sense wire. (Bestech BMS comes to mind)
I've also seen some people connect the sense wire from B- to the B- port on the BMS.
I made that mistake once and thought that the first cell was sagging more than the rest


But if the Cell is still lower when the pack is resting then I guess that would confirm what you said.

[larsb]

Since it’s cell 10 it’s actually in the middle of the pack (not b-) and there are separate balance wires on all cells

I can see that cell dives from full voltage to bms cutoff with just one max pull, it’s gotten worse and worse..

[jonnydrive]

hello Larsb!
I just read all your posts of rieju and Votol, you are a super-valid QS build expert guy

....meantime I didn't made any changes to my build, it still works greatly...but now I can compare e-trial with my ktm exc 400.
With my actual e-trial settings (Votol 150 @120 amps busbar) thare is no chance to do the same hard dirt tracks I do with ktm.

On your experience, what do you suggest as maximum busbar courrent/current-limiting settings to reach a good trade off between overheating/controller-fault and power?

thanks

Jonny

[larsb]

I think silentenduro and bartosh knows better. I cannot seem to provoke limiting.. full phase amps and 250A bus bar is my long term setting. I’ve been thinking of trying to reflash the APT96600 controller, try 30S and 1:7 gearing. This way i’ll get close to 400Nm on the rear wheel and 100km/h top speed, should be enough for me..

[larsb]

..but now I can compare e-trial with my ktm exc 400.
With my actual e-trial settings (Votol 150 @120 amps busbar) thare is no chance to do the same hard dirt tracks I do with ktm.

Had to look up the specs for the bike, 32kW output and six gears.. you’ll never be able to match it
If you switch to me1302 motor and sevcon controller, could be possible to at least match the power if you want to. Go for it

[larsb]

I’ve gotten tired of switching between winter and summer tyres and the old wheels are about done. Even the brake discs are getting too thin so i decided to get an extra/summer wheel pair. This will be the start of a major overhaul of the bike

I’ll change to chain drive, 11/80 gearing and try 30S voltage with the reflashed and resurrected APT96600 controller.

The new wheels came complete with tyres, 52t sprocket and brake discs. I replaced the sprocket with an 80t from here:
https://www.zahnriemen24.de/a/41324-ket ... quantity=1

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This is 08b standard and fits 428 chain.

First issue: The brake discs have gotten a lot larger on the later Rieju mopeds.. From 185 to 200mm on the rear and from 220 to 300mm on the front.

It’s clear that the rear brake disc requires a larger bracket for the brake. Some drawing work and an hour with a drill and hacksaw resulted in this:

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Works perfectly

The front brake spacing might be harder to solve as it’s not originally mounted with a bracket.

[larsb]

Replacing the pulley motor with the new chain drive.

I don’t really know how far it’s been run, guess about 15000-20000 km driving and two winters on salted roads. It has taken it’s toll. Both front and rear pulley is worn out but otherwise it’s running perfectly
I am really happy with the performance of this motor.

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[larsb]

ordered a new DC DC capable of 30s voltage/126V:
https://www.aliexpress.com/item/4000751 ... 5cR4y&mp=1

Will order three LED drivers and put in series for adjustable charging on the cheap (voltage and current):
"Mean Well ELG-150-42AB" has adjustable current and voltage by potentiometer so i can choose 4V charge at 120V or 4.2V charge at 126V
https://www.tme.eu/se/en/details/elg-15 ... mean-well/

ordered this 32S smart BMS from ICGOGOGO store at aliexpress:
https://www.aliexpress.com/item/3282646 ... 4c4ddXqiz7

[tylerwatts]

I thought you were just switching to chain drive Lars. Looks like a full rebuild is kicking off... Hope it goes well, bike will be great by the looks of it.

Cheers
Tyler

[larsb]

I always thought about going to higher voltage with the 3000w mid drive. The (low) 5 pole pairs should reduce eddy losses a lot: The 80100 motors with 7 pole pairs top out at 7krpm before eddy losses gets too high (or so i’ve read..)

Eddy losses are proportional to pole pairs squared so in comparison 5*5/7*7 equals close to half the losses at same rpm and the 3000w mid drive might therefore be able to take guesstimately 7000*sqrt(2)=9900 rpm

With 126V it should be possible to get 7800-9450 rpm (depending on flux weakening) if motor doesn’t explode before - we’ll see

[larsb]

Cardboard engineering a rear fender mount

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It’ll be 3d-printed by a friend, always nice to get from design to reality in such a short time

[tylerwatts]

Wow that looks promising! I'm sure the qs motor will safely do those rpm but just be careful how many amps you are using at that voltage. Good to think about it as kVA max so more V means less A for given max kVA otherwise insulation starts failing because of heat and wear and high voltage spikes quickly make short our paths that burn windings up.

But you seem to be sensible and know what you are doing so I look forward to seeing how the bike performs.

Cheers
Tyler

[larsb]

What i’ll be running won’t be even close to the limits of the wire insulation. Even the max 32kW is within the boundaries of the specs.

What will be the limit is
Eddy losses which will increase squared with rpm. The thin laminations, segmented magnets and low pole count of this motor should reduce this risk. I’m not so concerned and noload current will show if there’s an issue.

Centrifugal forces and imbalance. I’ve seen a spec where max rpm was stated as 7500 rpm for this motor so maybe 9000 rpm is too much. It might burst in an interesting way.

Erpm. Not sure that the APT controller can do 50kerpm, we’ll see.

[j bjork]

It will be interesting to see for sure
How about the dyno? Would´nt it be perfect to test there?

[larsb]

yes, off course.. It's a bit stupid but i have no ride now and i normally don't use anything else than the moped. I want to be back riding electric.

[larsb]

First driving tonight with the new motor at 72V and the new 1:8 gearing. Thought it was a bit disappointing at first but realised i had restricted settings

Now it easily pops a wheelie and is more than i can handle since i’ve been going smoothly for too long, throttle needs to be feathered

The wreck

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I need to change front brake caliper, the pistons were rough and scored already when i started to change pads.. i guess 22 years is enough lifetime for a moped brake.

Looking forward to the 30s, that will be interesting!

[tylerwatts]

That is looking great larsb. The new wheels are very cool too! And performance sounds excellent. Good thing the brakes are bigger!

One thing I notice, your battery is mounted very high and there looks like plenty space to stack them vertically inside the frame, do they not fit? Even parallel to the front frame upright bar? I can't see where the controller is mounted. And how will you make 30s battery? Isn't your modules already set sizes from the Volvo battery? I can't find the post.

Cheers
Tyler

[larsb]

There’s a link to the battery cover build earlier in this thread. Batteries are mounted high to fit the third module inside the frame later on, each module is 10s/36V. More than three cannot be fitted unless one is stacked on top of the upper two and two more as ”sidebags” in the rear (but i think that would be super ugly.)

Controller is fitted under the seat, it’s only slightly visible in this pic. I’ll need to figure out a splash cover for it for the winter riding.

[gbeals]

I didn't want to hijack this thread so I reached out to the OP. It does seem my questions may benefit others, so I'll attempt to be brief but provide enough details to allow an understanding on what i'm attempting to do.

I'm looking to build a Trials Motorcycle for trail fun; Not competition large jump type stuff. I like the Electric Motion build, but I like to build things. 40ish MPH is more than enough but torque 450 N.m is the goal - Yes that is a lot but is what new Electric Trials bike have; so close is goal. I'm not looking to implement on a clutch on this build. I'm not too good with 2 stage reduction, so go big on the motor and just do 10t/50 or more teeth in rear was my thought. I don't know how that affects other aspects of my build. Background: I have some good skills. New to electric motors, but definitely at home with everything mechanical.

I'm looking at 2 stage, and it doesn't look overly complex to make one.... I've seen two basic designs Stage 1 on opposite side of 2nd stage and then Stage 1 and 2 on same side of motor.

My questions...

• Am I wrong to assume its better to go big with 4000 QS motor and go direct 10/50+ teeth in the wheel?

• Is it better to go as small as I can with the motor (3000 QS) and use gearing to generate more torque for the savings it would bring me on battery?

• Any parts web links or videos on 2 stage reductions - It cant be as simple as a plate and some gears/shaft/bearings? Belt or Chain?

Same Side


Different Side


Single Stage Reduction

[larsb]

.. 40ish MPH is more than enough
Torque 450 N.m is the goal - Yes that is a lot but is what new Electric Trials bike have; so close is goal. I'm not looking to implement on a clutch on this build. I'm not too good with 2 stage reduction, so go big on the motor and just do 10t/50 or more teeth in rear was my thought. I don't know how that affects other aspects of my build. Background: I have some good skills. New to electric motors, but definitely at home with everything mechanical.

I'm looking at 2 stage, and it doesn't look overly complex to make one.... I've seen two basic designs Stage 1 on opposite side of 2nd stage and then Stage 1 and 2 on same side of motor.

My questions...

• Am I wrong to assume its better to go big with 4000 QS motor and go direct 10/50+ teeth in the wheel?

• Is it better to go as small as I can with the motor (3000 QS) and use gearing to generate more torque for the savings it would bring me on battery?

• Any parts web links or videos on 2 stage reductions - It cant be as simple as a plate and some gears/shaft/bearings? Belt or Chain?

Your application is very much dependent on what trials means for you, if you want instant 450Nm torque and rockhopping then i’d go for 2-stage 3kW motor and 1:10 gearing or so.

My build with 1:8 single reduction requires a huge sprocket that might be in the way for true trials riding where you’ll likely want as much ground clearance as possible.

As you’re not looking for high top speed then 4k motor and single reduction is not the best, that is not the most efficient way of building it for high torque.

And yes, 2-stage is as simple as some bearings, axles and plates. Which configuration you choose is dependent on your available space. I’d think opposite side jackshaft is better since forces are more balanced on the shaft and it likely takes up less space. If you’re in the US then staton-inc.com and sickbikeparts.com has a lot of parts (mc master carr etc off course also)

Come to think of it, the 3k motor would be easy to do a 2stage gearing on since its’ got so many fixation holes on both sides. Two plates could easily serve both as mounts and jackshaft holders.

You want a battery capable of 200A dc and a controller capable of 500A phase current to get the most out of this motor.

[larsb]

Starting to build a carbon fibre box under the seat for the APT96600 controller. I love/hate carbon layups, the high cost of mistakes makes it a ”win big or lose big” game.

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All the f*ckups are yet to be done, don’t know yet what they will be

[larsb]

Rear fender and mounts are printed, like it! I might do a carbon overlay on the fender to give it some strength, i’ll see when i get it.

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[larsb]

Adding some epoxy/carbon layers to the controller box with vacuum forming.

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I have a bad feeling about this run, the vacuum bag sucked in so quickly that i didn’t have enough hands to hold it in place in the corners. I tried to release vacuum and reposition it but there’s a risk that the layers were shifted, especially along the edges. Mierda!

We’ll see in 8 hours how it turned out.