Rieju 50cc conversion

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drewjet   10 kW

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Re: Rieju 50cc conversion

Post by drewjet » Sep 25 2018 4:40am

Looking Great!

larsb   10 kW

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Re: Rieju 50cc conversion

Post by larsb » Sep 26 2018 3:04pm

Thanks drewjet!

I tried some jwpf type connectors today, must say i love the size and feel.

Look at this little guy: JWPF IP67/three pin connector -it's barely larger than the wires:
image.jpeg
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larsb   10 kW

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Re: Rieju 50cc conversion

Post by larsb » Oct 07 2018 11:13am

I got the QS motor, EM150s controller and belt drive running today.

Man, what a difference to the kelly kls / revolt combo!! :D :D :D

It pulls more than the kelly/revolt even though the kV of the motor is close to the double and geardown is lower so current delivered must be high. If i get more than 6 months before the controller breaks then i'd recommend it 100% - we'll see!

Max setting for phase current for the Votol controller is 470 Amps..
Last edited by larsb on Oct 14 2018 2:51pm, edited 2 times in total.

larsb   10 kW

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Re: Rieju 50cc conversion

Post by larsb » Oct 08 2018 3:34pm

It seems the domino throttle doesn't work with the Votol EM150s controller, it only powers the motor from a standstill.
The controller powers down as soon as the switch in the throttle is activated and won't start again until from a standstill. I guess the switch breaks the power in the throttle drive circuit which the controller senses and goes into fault mode. That's annoying as i really like the Domino throttle - it's worth it's price.

I switched to a crappy half twist throttle i had and it works fine. Only "minor" flaw is that i trimmed this throttle (when in a low power system) to turn on instantly so power ramp up is really steep. I nearly crashed on my first ride just taking off, the Rieju's got a lot of oomph now :lol:

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fechter   100 GW

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Re: Rieju 50cc conversion

Post by fechter » Oct 09 2018 8:49am

There should be a way to make the Domino throttle work. Most likely you just need to add some fixed resistors in series with the ground and 5v lines so the signal stays in the same range as a hall throttle. If the signal gets too high or too low, the controller senses a fault and shuts down.

Do you know what the resistance of the Domino throttle is? With Magura throttles I think 1.2k was needed for the resistors.

Below is a diagram of a setup using trimmer pots. This works too and is adjustable. Fixed resistors are much smaller but you need to get the value right.
Magura resistors 2.gif
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larsb   10 kW

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Re: Rieju 50cc conversion

Post by larsb » Oct 09 2018 9:08am

Thing is it works from zero to full throttle without fault, it's when the throttle switch in the domino is activated when you release the throttle during driving that the controller faults.

My guess is that the switch breaks the 5v to ground connection (for safety reasons in case of shorted pot) which faults the controller. I don't think it's fixable with resistors because of this..

What would the diagnostic be otherwise? From standstill throttle low voltage is ignored but after start of rotation it faults at too low/zero volt of throttle?

What is the lowest output of a hall throttle, is it more than zero?

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fechter   100 GW

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Re: Rieju 50cc conversion

Post by fechter » Oct 09 2018 12:46pm

Minimum output for a typical hall throttle is around 0.7v.

I have never seen a Domino throttle first hand. I would think the switch would be wired separately from the pot to operate a contactor. You could use an ohmmeter to see what the switch is doing. It may be possible to take the throttle apart and bypass the switch.
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madin88   100 MW

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Re: Rieju 50cc conversion

Post by madin88 » Oct 09 2018 12:58pm

fechter wrote:
Oct 09 2018 12:46pm
I would think the switch would be wired separately from the pot to operate a contactor.
Thats how it is.

Image

larsb   10 kW

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Re: Rieju 50cc conversion

Post by larsb » Oct 09 2018 1:04pm

Switch seems to be independent from the throttle signal based on the picture.. Then it should be the throttle low voltage error that shuts down the controller.
Throttle low volt is programmable but it does not change the values in the program even though i save..

I will measure the Domino.
Last edited by larsb on Oct 14 2018 2:54pm, edited 2 times in total.

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Re: Rieju 50cc conversion

Post by larsb » Oct 09 2018 1:26pm

I measured the throttle:
- Switch is not connected to throttle signal circuit (great!)
- Low resistance (with wiper closest to the measured contact) is about 20ohm on one side and 40ohm on the other.
- max resistance end to end is 5.5kOhm

If i put 1 kOhm resistor on both in and out side then signal span would become 0,7-4,3V, that should do it.

Thanks guys!
Last edited by larsb on Oct 11 2018 12:58am, edited 1 time in total.

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fechter   100 GW

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Re: Rieju 50cc conversion

Post by fechter » Oct 10 2018 12:37pm

larsb wrote:
Oct 09 2018 1:26pm
I measured the throttle:
- Switch is not connected to throttle signal circuit (great!)
- Low resistance (with wiper closest to the measured contact) is about 20ohm on one side and 40ohm on the other.
- max resistance end to end is 5.5kOhm

If i put 1 kOhm resistor on both in in and out then signal span would become 0,7-4,3V, that should do it.

Thanks guys!
Yep, that should do it. The ground side resistor will affect how much 'dead band' there is before the motor starts going. It's nice if the dead band is not too large. If you find too much dead band, increase the ground side resistance.
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larsb   10 kW

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Re: Rieju 50cc conversion

Post by larsb » Oct 13 2018 6:35am

Changed my mind, wanted to keep the available throttle band and since i had no issues for the high throttle i just added 470 Ohm to the low/ground side. That should raise the low voltage output to 0.4V
Result is a decent amount of dead band, really good throttle response and no controller faults :D :D
IMG_2543.JPG
IMG_2543.JPG (402.12 KiB) Viewed 615 times
The Rieju now tops 105km/h when it's unrestricted so i'm thinking of (eventually) doing a change in downgearing, 22:140 instead of 22:105 to give max 80km/h 8)

The belt drive is great so far, only sound from the drivetrain is from the idler wheel which has an audible hum.
I think idler might be too small, could be at least 22t, also probably slightly out of shape due to the milling in my diy CNC. Let's hope it doesn't lower the belt life.
Last edited by larsb on Oct 13 2018 3:20pm, edited 2 times in total.

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fechter   100 GW

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Re: Rieju 50cc conversion

Post by fechter » Oct 13 2018 11:44am

You could put the idler on the smooth side of the belt. The idler pulley could be smooth too. This would reduce the noise a lot. I see this done on many other belt applications.
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larsb   10 kW

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Re: Rieju 50cc conversion

Post by larsb » Oct 13 2018 1:12pm

The tension problem is there's slack created during suspension compression. I couldn't fit an outside idler on the swing due to many reasons (primarily couldn't find the space)

An outside frame fixed idler gives lowered tension during the suspension compression but an inside, frame fixed idler increases tension as the slack grows (since the suspension moves towards the tensioner)

I think i have the best balance with the idler i've got, but idler wheel itself could be better..
Last edited by larsb on Oct 14 2018 3:34pm, edited 3 times in total.

larsb   10 kW

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Re: Rieju 50cc conversion

Post by larsb » Oct 13 2018 2:20pm

Another pic from today, i had a great time riding/programming the controller.
The bike is a little rough around the edges with the scuffed paint and scratches all over but i like that :D
IMG_2556.JPG
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larsb   10 kW

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Re: Rieju 50cc conversion

Post by larsb » Oct 14 2018 3:41pm

The controller cutouts are annoying, can't just smash the throttle wide open as it will cutoff power. I can still get hard takeoffs but i have to be slightly slower on the throttle.

I have three battery packs with a LOT of wiring to the controller. I'm thinking of trying a capacitor bank if the cutouts are caused by the battery/wires inductance.

Is there any guide what capacitors to use, how many etc?

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fechter   100 GW

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Re: Rieju 50cc conversion

Post by fechter » Oct 14 2018 11:19pm

Capacitors won't help.

You can lower the current limit on the controller, lower the low voltage cutoff on the controller, or get batteries that don't sag so much.
If the controller is programmable, you can try to dial it in so it is just below the tripping point.

The best thing is better batteries, but expensive.
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Re: Rieju 50cc conversion

Post by larsb » Oct 15 2018 3:53am

I don't understand what you mean? Cutoffs are not from low volt error, i never reach that low.

I guess that current spikes push controller into high current error but i cannot be sure.

What is your guess Fechter?

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madin88   100 MW

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Re: Rieju 50cc conversion

Post by madin88 » Oct 15 2018 4:18am

larsb wrote:
Oct 15 2018 3:53am
I guess that current spikes push controller into high current error but i cannot be sure.
That could be the case if your battery deoesn't sag to LVC, so if you add caps close to the controller to reduce the spikes it could solve the problem.
It would also help (lower the inductance) if you twist the battery wires, or put them as close together as possible.

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Re: Rieju 50cc conversion

Post by larsb » Oct 15 2018 5:48am

I'll shorten the wires and tape them together as a first test.

A lot of info in this thread, close to 100 pages :D https://www.rcgroups.com/forums/showthr ... orkarounds

I have total length of wire over 1.2m, following cap bank could be as large as 20.000 microfarad.. Rubicon ZL caps recommended. Total cost will be about 70USD for this.
Last edited by larsb on Oct 17 2018 12:47pm, edited 2 times in total.

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fechter   100 GW

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Re: Rieju 50cc conversion

Post by fechter » Oct 15 2018 8:20am

When the controller trips, there should be some way to tell what caused it. Not sure about the model you have, but many of them have a status LED that will blink a code telling you the problem.
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Re: Rieju 50cc conversion

Post by larsb » Oct 15 2018 11:45am

No status LED on the Votol controller..

But you gave me an idea, i'll set low volt to zero just to rule out that it's the fault.

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fechter   100 GW

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Re: Rieju 50cc conversion

Post by fechter » Oct 16 2018 8:44am

Yes, try that.

I'm not familiar with that model controller, but most have some way to tell what is causing a trip.
The other thing to try is lowering the current limit. Try to get it as high as possible without causing any faults on full throttle.
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larsb   10 kW

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Re: Rieju 50cc conversion

Post by larsb » Oct 16 2018 8:53am

I will remove the high volt control also if current spikes could drive a high volt error.. It'll be interesting to see if it makes any difference

EDIT: I removed the low and high volt control, still there are cutouts.. could also be BMS on the old battery pack that trips at high current

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Re: Rieju 50cc conversion

Post by Yermommy » Oct 17 2018 8:24pm

larsb wrote:
Oct 16 2018 8:53am
I will remove the high volt control also if current spikes could drive a high volt error.. It'll be interesting to see if it makes any difference

EDIT: I removed the low and high volt control, still there are cutouts.. could also be BMS on the old battery pack that trips at high current
Definitely the BMS in that case. I ran my battery down too low this past weekend and the BMS cut everything off. I thought I would try running below 72v of charge, but the battery sagged too much, causing the BMS stopped all current. Only had to walk it back 1 mile in the city so it wasn't really that bad.

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