Brompton Cute Q70 question

TomCC

Just Joined
Oct 13, 2019
1
0
Hi everyone, long-time-reader-first-time-poster.

I can't find any examples of people using the Cute Q70 motor for a Brompton conversion - I'm amazed and confused! Am I missing something obvious? It seems to have been available a while and fits the front forks without having to spread them.

Assuming there's no reason it won't work, I'd appreciate some advice on the parts I'd need for a conversion - BMS don't offer a complete conversion kit. How does the below look?
1. Q70 motor, 328 rpm (https://bmsbattery.com/motor/868-16985-q70-36v250w-front-driving-v-brake-hub-motor.html#/214-rpm-328)
2. Bottle battery/ built in controller (https://bmsbattery.com/ebike-battery/932-17760-36v10ah116ah14ah-new-bottle-battery-pack.html#/138-color-silver/323-controller-s06s_hall_sensor_sine_wave/380-display-lcd3/514-cells_capacity-samsung_35ah_14ah) with these selections:
- Display: LCD 3
- Controller: S06S Hall sensor sine wave
- Cells/capacity: Samsung 3.5AH / 14AH
3. S-V12 pedel sensor (https://bmsbattery.com/parts/705-dual-hall-sensor-12-signals-easy-assembling-pas-ebike-kit.html)
4. Thumb throttle (https://bmsbattery.com/parts/904-thumb-level-throttle-with-waterproof-plug.html)

Total cost incl. shipping = £390

Are all of these parts compatible? Are they easy to fit? I have no electrical know-how ( can't solder, don't have a volt meter, wouldn't know what to do with one if I did) but I'm a competent home mechanic. My plan is to mount the battery unit on the Brompton main frame, in front of the seat pillar.

Any and all advice would be greatly appreciated.

- Tom
 

Paradad

Pedelecer
Nov 2, 2019
30
1
So let's look at a recipe for about 10km range :
Q70 - MOTOR (thanks Tom)
KT sinewave controller with brake cutoffs and PAS - CONTROLLER
KT LCD4 Screen - small and neat - SCREEN (Thanks @vfr400 )
Small 36v 5.8 Ah bottle battery - BATTERY (ditto!)
Bag for the battery - BAG
Spokes Calculator
Rim
This post has got me interested & I'm thinking of putting this together - maybe with a bigger battery but I think this would give a pretty and useable set up.
Thoughts?
 

Collis123

Finding my (electric) wheels
Aug 24, 2019
11
0
So let's look at a recipe for about 10km range :
Q70 - MOTOR (thanks Tom)
KT sinewave controller with brake cutoffs and PAS - CONTROLLER
KT LCD4 Screen - small and neat - SCREEN (Thanks @vfr400 )
Small 36v 5.8 Ah bottle battery - BATTERY (ditto!)
Bag for the battery - BAG
Spokes Calculator
Rim
This post has got me interested & I'm thinking of putting this together - maybe with a bigger battery but I think this would give a pretty and useable set up.
Thoughts?
How straight forward do you think it will be to add the motor to the rim and spokes?

And having used a Swytch kit that is limited at 15mph, I recommend a bigger battery to give you a bit more juice on the flats. Just put the battery in a front bag because it will probably be too heavy to mount on the handlebars.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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Basildon
You don't need a bag for the battery. It's fully waterproof. Just fit a bottle holder on the handlebars or wherever you want it. If you're going to use a bag, a bare cell-pack with BMS will be a lot cheaper.
 

Paradad

Pedelecer
Nov 2, 2019
30
1
Hi @Collis123 , got be honest, haven't done it for years. I used to find wheel building tough but satisfying.. I'd only do it now if i couldn't buy what i need ready made. In this instance I think I'll do it to use the q70 - and to be sure of a good quality front wheel. In this case the kits on ebay are just too much of an unknown quantity for me. I know there will be much swearing ahead if I get started.... :D
@vfr400 - yup, good point. bag not needed but i think is looks pretty& is also convenient option for carrying the battery about off the bike. That said I am looking at alternative batteries. I share concern about range, so I'm still lookin at that. The rest of it looks okay to me. Im tempted to start hitting the "sod it" buttons and start ordering soon.
That said I just found a thread on this forum of interest. Same idea using a fatter motor:
 
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Collis123

Finding my (electric) wheels
Aug 24, 2019
11
0
Hi @Collis123 , got be honest, haven't done it for years. I used to find wheel building tough but satisfying.. I'd only do it now if i couldn't buy what i need ready made. In this instance I think I'll do it to use the q70 - and to be sure of a good quality front wheel. In this case the kits on ebay are just too much of an unknown quantity for me. I know there will be much swearing ahead if I get started.... :D
@vfr400 - yup, good point. bag not needed but i think is looks pretty& is also convenient option for carrying the battery about off the bike. That said I am looking at alternative batteries. I share concern about range, so I'm still lookin at that. The rest of it looks okay to me. Im tempted to start hitting the "sod it" buttons and start ordering soon.
That said I just found a thread on this forum of interest. Same idea using a fatter motor:
Let us know what you decide to do! I can't reiterate enough how much I don't think the battery you have selected will be sufficient (unless you are only planning on going very short distances). The predicted range is never as good as expected in reality.
 

Collis123

Finding my (electric) wheels
Aug 24, 2019
11
0
What about one of these batteries? Would give you the extra range and speed? There might be a smart way of mounting it on the front of the bike above the wheel. Going to cost a bit more money, but you could come up with something pretty impressive?




Or this one if you want to save money and just place it in a bag? This is smaller as well.

 
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Paradad

Pedelecer
Nov 2, 2019
30
1
@TomCC - you've stayed very quiet :) So, inspired by this thread I've decided to go for a 36v 10AH Hailong battery and the Cute Q70. It won't be as pretty as some but I think will work well enough on the cross bar and shouldn't interfere with folding while also giving me the longer range I'm looking for. @Collis123 I think 48v may be too much for this wee motor & personally I'd be concerned about over heating. My main aim for this is to avoid sweatyness rather than increase speed, so 36v it is.
I'll let you know how I get on in a few weeks from now...
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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@TomCC - you've stayed very quiet :) So, inspired by this thread I've decided to go for a 36v 10AH Hailong battery and the Cute Q70. It won't be as pretty as some but I think will work well enough on the cross bar and shouldn't interfere with folding while also giving me the longer range I'm looking for. @Collis123 I think 48v may be too much for this wee motor & personally I'd be concerned about over heating. My main aim for this is to avoid sweatyness rather than increase speed, so 36v it is.
I'll let you know how I get on in a few weeks from now...
I think you'll find that battery and the ones in the post above yours too big and heavy for a Brompton. Personally, I wouldn't go any higher than 30 cells (1.5kg). 30 cells can get you a good 9Ah, which would take you at least 30 miles of moderately hilly riding without sweating.

The guy who rides the Brompton I converted said that even with a 30 cell battery, the bike was still too heavy to carry anything much more than into the boot of a car. He concluded that if you want to fold and carry the bike, a removable battery would be essential.
 

Jonah

Esteemed Pedelecer
Aug 23, 2010
882
246
EX38
I think you'll find that battery and the ones in the post above yours too big and heavy for a Brompton. Personally, I wouldn't go any higher than 30 cells (1.5kg). 30 cells can get you a good 9Ah, which would take you at least 30 miles of moderately hilly riding without sweating.

The guy who rides the Brompton I converted said that even with a 30 cell battery, the bike was still too heavy to carry anything much more than into the boot of a car. He concluded that if you want to fold and carry the bike, a removable battery would be essential.
I concur, small and light suits the Brompton best, in a small removable bag on the luggage bracket. 30 cells would give you 10.5ah with decent cells. Also, now that narrower motors are available I would avoid the options that require stretching the forks.
 

Collis123

Finding my (electric) wheels
Aug 24, 2019
11
0
I concur, small and light suits the Brompton best, in a small removable bag on the luggage bracket. 30 cells would give you 10.5ah with decent cells. Also, now that narrower motors are available I would avoid the options that require stretching the forks.
I tend to disagree. I used the swytch kit for a while and that was about 3.5kg or maybe even 4. As long as you mount it low down by the wheel it will have a low centre of gravity and you won't even feel the extra weight.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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Basildon
I tend to disagree. I used the swytch kit for a while and that was about 3.5kg or maybe even 4. As long as you mount it low down by the wheel it will have a low centre of gravity and you won't even feel the extra weight.
Do you fold it frequently? If so, how do you deal with it? How many cells in your battery?
 
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Jonah

Esteemed Pedelecer
Aug 23, 2010
882
246
EX38
I tend to disagree. I used the swytch kit for a while and that was about 3.5kg or maybe even 4. As long as you mount it low down by the wheel it will have a low centre of gravity and you won't even feel the extra weight.
My 10ah Swytch kit is 3.5kg but mounts on the handlebars. I find it ok because it’s so much lighter than the Sparticle kit I had previously (about 9kg) which was mounted on the luggage bracket. A heavy weight on or over the front wheel, even if low down noticeably effects handling. 3.5kg isn’t bad but 2kg is better. I wouldn’t want much less than 10ah though.
 

Collis123

Finding my (electric) wheels
Aug 24, 2019
11
0
Right. If I was thinking of DIY'ing a brompton now I would seriously consider just waiting for the new Swytch kit that will be available next year. The battery is tiny. Not going to be possible to DIY anything close atm.
 

vfr400

Esteemed Pedelecer
Jun 12, 2011
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Right. If I was thinking of DIY'ing a brompton now I would seriously consider just waiting for the new Swytch kit that will be available next year. The battery is tiny. Not going to be possible to DIY anything close atm.
The Swytch kit just uses standard battery cells and motor. The kit gives an easy solution, but you can get the same yourself. The battery is just a a 20 cell one using 2500mAh cells, like Samsung 25R to give 180Wh. That's enough for about 15 miles with some hills. the larger capacity battery will use 3500 mAh cells. I hope they chose those wisely. The motor shown in their photos is a Q100 (Q70 for narrow forks).
 
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vfr400

Esteemed Pedelecer
Jun 12, 2011
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Basildon
If you are looking for lightweight with decent capacity this might be worth considering in 10S2P format as long as you are not running over 15 amp controller.
That pack uses 21700 cells so a lot bigger than 18650s. It's more or less equivalent to a 30 cell 18650 pack.
 

Paradad

Pedelecer
Nov 2, 2019
30
1
Oh now you've almost made me wish I'd held back a little longer! :D
However, I'm commited now. It's a fair point about the weight for carrying - and partly with that in mind I was considering a set of two (or more) smaller batteries which could be very effective (I think the bottle with that grey case from rockbros looks like a great combo). However - I very rarely carry my Brompton anywhere. It lives in the back of the car and comes out when I get to the city limits so I wanted enough power to get in and out with a bit to spare. I *think* it'll look Okay but I'll post some photos later and let the pedelecs community judge !
The key factors for me were then:
- range (based on 80% charge)
- locakable if I have to leave the bike in town
- frame fixings and case part of the package
- low impact on the overall form factor of the bike when folded
Others will surely have different requirements and I really hope we get to see different builds coming out and see how they get on. Especially some more powerful rear hub designs... :p
 
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Kwozzymodo

Pedelecer
Sep 9, 2017
177
40
62
Lincolnshire
I am going to try and build a ‘Brompton Kit’ in the next few weeks. I think you need the Q70 front wheel motor as a starting point, as the fork widths on my folders are <80mm. I’ll report back with pics once The Project is complete.
 

Paradad

Pedelecer
Nov 2, 2019
30
1
So my Q70 arrived this week. The details provided by BMSBattery have been ever so slightly less than useful!

Does anyone have a colour coded wiring diagram? It's even possible the wiring is the same as others "Q" series motors I guess. Any thoughts anyone?