Building a light ebike with Q100 motor : advices ?

Jil

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Sep 7, 2017
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Bordeaux, France
Hello,

I'm planning to build a light gravel e-bike (target : below 14kg with battery), in the same spirit than the Orbea Gain.

I'm looking for some advices :
- which model of Q100 is the most indicated ? I'm looking for a max continuous power of 250W, and the lightest/smallest motor. I'm thinking about the Q100 CST.
- Is it possible to use it safely on the long term in 48V or even 52V (it is branded for 36V) ?
- what are the alternatives to the Q100 ? I'm thinking also about the Bafang G370, or the Aikeman P250.01
- what are the best and smallest controllers for the Q100 (or the alternative motors) ?
- I would like to use a torque sensor on the bottom bracket (like this one : https://www.bafang-e.com/en/components/component/sensor/sr-pa3132st.html), do you think it's a good idea ? Or a simple PAS will do the job ?
- I'm looking for a small device for controlling the power, with no screen (like on the Orbea Gain, just a button with different color lights to indicate the assistance level). What off-the-shelf models could do the job ?
- my battery should be a 2P/13S or 2P/14S.

Thanks in advance for your help !
 
The Q100 used to be an Aikema clone, but now they all seem to be genuine Aikema, so they're the same thing.

Nothing is straight forward. Many of us have used the Q100C, which is a good motor, but it is quite wide at around 142mm if you have a disc brake. The other thing is that the spoke flanges are off-set from the centre, so you need a substantial dish in the wheel unless your frame is off-set too.

Secondly, there are three speed versions: 201 rpm, 260 rpm and 328 rpm. You have to chose your version carefully to match the voltage and your modal speed. This motor is not a torque monster, so it won't be able to hold a high speed without a lot of assistance from you. If you put the 328 rpm one in an MTB and used a 48v battery, something would burn, but it might work in a road bike as long as you don't use it for hauling you up hills. You have to decide how and where you want the power to help you before deciding which version and which voltage you use.

36v for light assistance. 48v for everything else. 201 rpm if you want the piwer mainly to help you up hills. 260 rpm if you want to maintain a high cruising speed. 328 rpm if you're a very fit cyclist who just wants the ultimate cruising speed.

The 201 rpm at 48v and 15 amps is the same as the 260 rpm at 36v and 20A. The 260 rpm at 48v and 15A is the same as 328 rpm at 36v and 20A.
 
I've just 'finished' my Q100h build using a Charge Plug 0 single speed bike and a 260rpm Q100H.

I've done around 50 miles so far and its been great :)

I went for a 52v 6aH battery that sits in a seat bag nicely and a 20amp PSW Power sine controller.

Using PAS, I normally keep it on level 2 / 3 and it handles most hills around my way fine. It shows around 400w max on PAS when going up a fairly steep hill.

I've set the controller to limit the amps slightly, its on '7' in the P settings (out of 10) so its probably pulling more like 17amps currently. This means I can use the throttle without worrying about it, full throttle gives me just under 800w.

So far, the motor battery and controller haven't got that warm even after hammering it for a 6 mile ride to work. The battery drops from 58v to about 52 ish after that ride too.

Fresh off the charger the top speed looks to be about 26mph, the single speed gearing does spin up a bit at that speed but its nice to keep it simple.

53203883_1146197002208801_4442658787263227616_n.jpg
 
Thanks for your help.
And nice build Lovelock :thumb:
 
Lovelock said:
I've just 'finished' my Q100h build using a Charge Plug 0 single speed bike and a 260rpm Q100H.

I've done around 50 miles so far and its been great :)

I went for a 52v 6aH battery that sits in a seat bag nicely and a 20amp PSW Power sine controller.

Using PAS, I normally keep it on level 2 / 3 and it handles most hills around my way fine. It shows around 400w max on PAS when going up a fairly steep hill.

I've set the controller to limit the amps slightly, its on '7' in the P settings (out of 10) so its probably pulling more like 17amps currently. This means I can use the throttle without worrying about it, full throttle gives me just under 800w.

So far, the motor battery and controller haven't got that warm even after hammering it for a 6 mile ride to work. The battery drops from 58v to about 52 ish after that ride too.

Fresh off the charger the top speed looks to be about 26mph, the single speed gearing does spin up a bit at that speed but its nice to keep it simple.

53203883_1146197002208801_4442658787263227616_n.jpg
Nice one.
 
Thanks guys :)

As a reference, I would probably go for the 201 rpm motor If I had to start again or when this motor blows.

I can only compare against a q128c at 201 but it did seem to climb a bit for effortlessly.

A 201 at 52v should still do 22 - 24mph and that is plenty, doing 26 on this is really starting to push where I feel comfortable on a push bike.

For the non UK. 26mph = nearly 42KMPH
 
Please don't double post;
https://endless-sphere.com/forums/viewtopic.php?f=2&t=99193&p=1452394#p1452364
It's considered to be bad form.
You could have just "bumped" your original post.
 
motomech said:
You could have just "bumped" your original post.

Yes you're right, I realized it a posteriori.
 
Following your advices, here is my final shopping list, what do you think about it ? Any additionnal advice ? Except components for the battery other than cells and BMS (I already have them), do you see anything missing ?

Motor (201 rpm) : https://bmsbattery.com/ebike-kit/618-16306-q100c-cst-36v350w-rear-driving-ebike-hub-motor-ebike-kit.html#/213-rpm-201
Controller : https://bmsbattery.com/controller/546-s06s-250w-torque-simulation-sine-wave-controller-ebike-kit.html
LCD : https://bmsbattery.com/parts/670-17063-s-lcd3-lcd-meter-for-s-series-controlers-ebike-kit.html#/137-color-black/485-connector_type-waterproof_connector
18650 cells : https://eu.nkon.nl/rechargeable/18650-size/lg-inr18650m36-3600mah-10a.html
BMS : https://www.aliexpress.com/item/Lithium-Li-ion-Battery-Power-Protection-Board-10S-36V-16A-BMS-PCB-PCM-Board-for-Ebike/32955001373.html?spm=2114.search0104.3.22.32134b2dLnmH3R&ws_ab_test=searchweb0_0,searchweb201602_6_10065_10068_319_10892_317_10696_10084_453_454_10083_10618_10304_10307_10820_10821_537_10302_536_10902_10843_10059_10884_10887_321_322_10103,searchweb201603_54,ppcSwitch_0&algo_expid=8358d4d4-acc0-4579-b812-87522b3466fd-3&algo_pvid=8358d4d4-acc0-4579-b812-87522b3466fd&transAbTest=ae803_3
Wires : https://bmsbattery.com/parts/603-copy-wire-for-s-series-display-meter-ebike-kit.html
https://bmsbattery.com/home/910-q-series-motor-cable.html

I already have PAS and speed sensor :
https://bmsbattery.com/parts/579-ten-poles-pas-pulse-padel-assistant-sensor-ebike-kit.html
https://bmsbattery.com/parts/661-king-meter-speed-sensor-ebike-kit.html
 
Hi Docw,
By "balance" you mean equalizing the tension during charge and discharge ?
Why do you say there is no balance function ?
A BMS is clearly made, among other things, to balance your cells. How do explain the connection of this BMS to each cell if there is no balance function ?
 
No mention of balance current in the specs.

A BMS usually stops charging when any single group reaches the maximum set point, usually 4.20 volts. If you have a situation where one group is at 4.1 or 4.0, those groups never reach full charge unless the BMS can balance them. It does this by discharging the high group slightly, and then re-starts the charging. It keeps doing this til the whole pack is even. Might take a long time.

Like you, I originally thought all BMS circuits would naturally include balancing. Many do not.

Some users here don't want balance circuits. In that case, the connections to each cell are only used to detect overcharge and undervoltage..
 
You don't need the motor cable because it already comes with one and there are better BMSs. On Aliexpress/Ebay, there are some good small ones that give 20A and have all the functions you need. You don't need that LCD wire either.

Did you see this battery I made?
https://www.pedelecs.co.uk/forum/threads/how-to-make-a-lightweight-battery.28437/
 
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