Hi [mention=23760]Collis123[/mention] , 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....

[mention=4809]vfr400[/mention] - 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:

https://www.pedelecs.co.uk/forum/threads/wheel-building-tongxin-in-brompton-wheel.5090/page-2#post-65911

 

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.

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?

 

https://bmsbattery.com/ebike-battery/950-18000-48v10ah116ah14ah-li-ion-alloy-01-case-ebike-battery-pack.html#/137-color-black/514-cells_capacity-samsung_35ah_14ah

 

https://bmsbattery.com/ebike-battery/937-17937-48v125ah145ah175ah-bottle-10-frame-e-bike-battery-pack-with-usb-output.html#/509-cells_capacity-samsung_35ah_175ah

 

 

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

 

https://bmsbattery.com/ebike-battery/166-48v10ah-li-ion-shrink-tube-ebike-battery-pack-ecitypower-battery.html

Edited November 10, 20196 yr by Collis123

[mention=24280]TomCC[/mention] - 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. [mention=23760]Collis123[/mention] 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...

[mention=24280]TomCC[/mention] - 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. [mention=23760]Collis123[/mention] 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.

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.

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.

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?

Edited November 10, 20196 yr by vfr400

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.

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.

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).

Edited November 10, 20196 yr by vfr400

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.

https://enerprof.de/en/ebike-batteries/softpacks/36v-10s-batteries/202/softpack-battery-36v-10ah-bms-20a-xlr-3-with-m50?c=10

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.

https://enerprof.de/en/ebike-batteries/softpacks/36v-10s-batteries/202/softpack-battery-36v-10ah-bms-20a-xlr-3-with-m50?c=10

That pack uses 21700 cells so a lot bigger than 18650s. It's more or less equivalent to a 30 cell 18650 pack.

Oh now you've almost made me wish I'd held back a little longer!

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...

Edited November 10, 20196 yr by Paradad

I do like the look of that softpack [mention=12956]wheeliepete[/mention] !

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.

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?

It's even possible the wiring is the same as others "Q" series motors I guess.

I would think they are the same, no reason they would be different. What colours do you have?

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?

All motors are the same. Three phase wires, 5 hall wires and a speed sensor wire. The connectors will fit the controller directly. How do you need a wiring diagram?

All motors are the same. Three phase wires, 5 hall wires and a speed sensor wire. The connectors will fit the controller directly. How do you need a wiring diagram?

Hi, if I can unpack that a bit, what you're saying is that all motors from all manufacturers use the same wiring layout? Same number of hall sensors / wiring layouts and colour coding? If the connectors (when they arrive) are also standard then this may be a moot point but I'm genning up before the build. Could you point me to somewhere where the wiring is described ? I've not found anything .

I would think they are the same, no reason they would be different. What colours do you have?

Sorry Pete, I'm working back up the stack!

 

Here's a photo....

 

Sorry Pete, I'm working back up the stack!

 

Here's a photo....

 

[ATTACH=full]33202[/ATTACH]

 

The wiring in your pic above is the only standard with manufacturer's.

Unsensored hubs only have the three thicker phase wires Blue,Green & Yellow.

Sensored hubs have the three thicker phases and Five or Six hall sensing wires, Black, Red, Blue, Green, Yellow and some have a sixth white for a speed sensor.

 

I have Bafang, Yose , Aikema and Mxus hubs they all have the same motor wire colours in a moulded Julet connection and are totally universal in swapping over. Bafang mid drive is the same using a standard wire layout.

 

Over thinking and worrying isn't needed take it from us there is no real issue with marrying up hubs to controllers, except to make sure colour sequence matches if non julet connection is used.

Edited December 1, 20196 yr by Nealh

there is no real issue with marrying up hubs to controllers, except to make sure colour sequence matches if non julet connection is used.

Good to know, cheers

Just want ed to pick up on the point of wiring - it's incredibly unsual for even a ompany to stick to standards, very refreshing to know the ebike motors are sticking to a common standard. It has highlighted how little INkow about how themotoros actually work - can anyone recommend a site and can go to read and educate myself?

Thought I'd also note that the wheel parts have all finally arrived and I have built the Q70 motor into a Sun CR18 rim as suggested by VFR. 120mm spokes fit perfectly using a cross 1 lacing pattern.

can anyone recommend a site and can go to read and educate myself?

Try this one:

https://www.pedelecs.co.uk/forum/categories/electric-bikes.1/