QS 3000w midmotor

Electric Motors and Controllers
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PITMIX   100 W

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Re: QS 3000w midmotor

Post by PITMIX » Dec 03 2020 2:36am

Qs made an important commercial gesture on shipping costs when ordering a Qs 138 90H and they supplied the motor shaft for the 70H in addition to 2 different gears.
The video :
https://youtu.be/ExonkHtjLsg
Aixam 550 Twin retrophite Qs 138 70H, Thermo-Nucular electronics 24F, LG Chem 20s 60Ah

Shazzy   10 mW

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Re: QS 3000w midmotor

Post by Shazzy » Dec 07 2020 5:39pm

I have the new V2 138 motor with the spine shaft. I wanted to fit a 520 sprocket - anyone managed to do this without any issues?

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PITMIX   100 W

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Re: QS 3000w midmotor

Post by PITMIX » Dec 08 2020 2:17am

The latest version of the Qs 138 70h in version 2 is now available with the keyed motor shaft for a pulley and an adapter for a 428 14T pinion. It's good news.
https://fr.aliexpress.com/item/10050016 ... f02&is_c=N
Aixam 550 Twin retrophite Qs 138 70H, Thermo-Nucular electronics 24F, LG Chem 20s 60Ah

HrKlev   100 W

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Re: QS 3000w midmotor

Post by HrKlev » Dec 09 2020 2:18am

Shazzy wrote:
Dec 07 2020 5:39pm
I have the new V2 138 motor with the spine shaft. I wanted to fit a 520 sprocket - anyone managed to do this without any issues?
JTF1903 sprocket. Ebay got lots of them. Its a tight fit if the motor is brand new, but if it has been running with the sloppy stock sprocket it glides right on. Nothing a small dead blow hammer wont fix, though.
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DIY lightweight mid drive with torque sensing build thread: viewtopic.php?f=6&t=107622

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PITMIX   100 W

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Re: QS 3000w midmotor

Post by PITMIX » Dec 09 2020 7:31am

You should replace the 2 sprockets with larger diameter models to reduce the stress on the motor and reduction shafts as well as the chain. You can keep the same ratio between the 2 sprockets, but simply increase the number of teeth on the 2.
Aixam 550 Twin retrophite Qs 138 70H, Thermo-Nucular electronics 24F, LG Chem 20s 60Ah

HrKlev   100 W

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Re: QS 3000w midmotor

Post by HrKlev » Dec 09 2020 11:05am

Yeah, I probably should. Could not find a bigger sprocket for the gearbox than 12T, so I would have to get some custom made. I need to get this thing (6x6 atv) up and running asap, so I will have to go back and fix some things later.
DIY lightweight mid drive with torque sensing build thread: viewtopic.php?f=6&t=107622

Soap_62   1 µW

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Re: QS 3000w midmotor

Post by Soap_62 » Jan 03 2021 3:24pm

Hello, bringing up the sprocket thing again, i got the QS 138 90H 4kw with the Tapered Hub.
It comes with an 14t sprocket, wich looks very very bad :? , and i dont want to shred a chain on it.. :wink:

Did anyone find an fitting sprocket for this tapered shaft ? (looks like the Pulley mount shaft, page 11 this thread)

(tapered from 25mm to 21 with woodruf key)

larsb   1 MW

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Re: QS 3000w midmotor

Post by larsb » Jan 07 2021 3:43pm

It’s not a standard interface. best bet is to grind it down and just bolt the sprocket you want to the outside of the mount. Could be done with simple tools.

rider119   1 mW

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Re: QS 3000w midmotor

Post by rider119 » Jan 13 2021 3:11pm

PITMIX wrote:
Dec 03 2020 2:36am
Qs made an important commercial gesture on shipping costs when ordering a Qs 138 90H and they supplied the motor shaft for the 70H in addition to 2 different gears.
The video :
https://youtu.be/ExonkHtjLsg
How do you plan to swap the rotor shaft? Are the laminations just keyed in place? No epoxy or anything holding them there?

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PITMIX   100 W

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Re: QS 3000w midmotor

Post by PITMIX » Jan 14 2021 12:56am

I don't know it's not my motor and my friend hasn't tried replacing the shaft yet. For the moment he has welded the pinion, and if one day the shaft breaks he will replace it.
Aixam 550 Twin retrophite Qs 138 70H, Thermo-Nucular electronics 24F, LG Chem 20s 60Ah

guiga   1 mW

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Re: QS 3000w midmotor

Post by guiga » Mar 06 2021 10:39am

hey how do you guys remove the pulley from the motor? i got a QS 138 90H 4kw and already broke my bearing removal tool. the bolt nut was hard but my inpact wrench did the job.
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flippy   10 MW

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Re: QS 3000w midmotor

Post by flippy » Mar 06 2021 1:04pm

heat up the sprocket with a butane burner used for copper pipes.
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PITMIX   100 W

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Re: QS 3000w midmotor

Post by PITMIX » Mar 06 2021 1:37pm

You must use a plumber's claw wrench to lock the pinion and a wrench with an extension to remove the nut. With an impact wrench it does not work. The nut is glued with varnish, it needs to be heated slightly.
Aixam 550 Twin retrophite Qs 138 70H, Thermo-Nucular electronics 24F, LG Chem 20s 60Ah

guiga   1 mW

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Re: QS 3000w midmotor

Post by guiga » Mar 06 2021 5:41pm

Already remove the nut , now i have to wait for a new removal tool. I will try to heat up a bit carefully , dont wanna damage the seal.

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PITMIX   100 W

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Re: QS 3000w midmotor

Post by PITMIX » Mar 07 2021 1:37am

You don't need any special tool to remove the pulley just have a rubber mallet and a triangular shaped shim to insert between the pulley and the motor flange. With a few small blows of the mallet the pulley will come out. If you damage the seal it is easily replaced. The reference is written on it, it is a standard model.
Aixam 550 Twin retrophite Qs 138 70H, Thermo-Nucular electronics 24F, LG Chem 20s 60Ah

Stevebequik   10 mW

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Re: QS 3000w midmotor

Post by Stevebequik » Mar 07 2021 4:47pm

Does anyone have real world Kv’s of the 138 3kW vs the 4kW.
On my bike, I have a massive 82t rear sprocket to get the performance I’m looking for. But it’s just too easy for the chain to get full of mud and cause problems.
Wondering if the 4kW 138 90, may have a lower Kv.
Would love to be able to keep the simplistic single reduction.

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PITMIX   100 W

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Re: QS 3000w midmotor

Post by PITMIX » Mar 07 2021 5:06pm

The data of the engines are real in the descriptions. The Qs 3kW has an actual kV of 73. The Qs 4kW runs at 7000rpm maximum so the kV is 97.
Aixam 550 Twin retrophite Qs 138 70H, Thermo-Nucular electronics 24F, LG Chem 20s 60Ah

j bjork   10 kW

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Re: QS 3000w midmotor

Post by j bjork » Mar 07 2021 5:20pm

From what I can tell the kv of my 138 70h is 60, not 73.

Stevebequik   10 mW

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Re: QS 3000w midmotor

Post by Stevebequik » Mar 07 2021 6:32pm

I agree, my 70 has a Kv of 60 and this corresponds to the nuc controller reading of 300eKv for a 5 pole motor. The 2kw qs 120 only has a Kv of around 38.
Was hoping the 90h may of been less then the 70, but looks likes it could be much higher.

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