BROMPTON conversion (80mm wide)

Hans Bontinck

Finding my (electric) wheels
Feb 12, 2015
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Hi there!

I have a Brompton Rear Wheel to spare and am hoping to convert this using a front wheel pedelec hub.

Keyde seems to be a bit unreliable. So i'm considering this kit (http://www.h9.com.cn/product/?id=193).

1 The obvious question, is this one good value for money?
2 Will i be able to reuse the existing spokes of my once rear wheel (BWR S-A 3 speed)?

Thank you for your help
 
D

Deleted member 4366

Guest
It's unlikely that you can reuse your spokes, but a set of spokes is only about £7 from Ebay.

That kit looks OK, but if you get it and something goes wrong, you'll be pretty much on your own.
 

Hans Bontinck

Finding my (electric) wheels
Feb 12, 2015
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Hi D8veh,
Thank you for your reply.
But, this manufacturer is one of the most trustworty, right?
Would i better off buying the separate parts?
In an ideal world, i'd copy past a recent conversion of someone else. That would make my build more fool proof :).
 

trex

Esteemed Pedelecer
May 15, 2011
7,703
2,671
That ORK motor has 83mm axle width. You'll need to spread the fork a bit.
 
D

Deleted member 4366

Guest
Spreading the forks is no problem. They can go right up to 100mm.

I've just had another look at that kit. It has a frog battery. I don't know how well that fits to a Brompton, plus, some of the Chinese ones have weak mounts that crack. The controller looks a bit non-standard, so there won't be much help from here to wire it up or if it goes wrong.

The supplier is probably trustworthy like most of the Chinese ones, but you don't get any warranty. It's a shame Morphix has disappeared because he was selling some good stuff for Brompton conversions.

It might be better to get a Q85 and S06S, though the fastest one at 328 rpm will max out at 15 mph. If speed is important, you could try the 24v one at 36v, which would give about 22 mph, or the 36v one at 44v or 48v, which would mean using lipos to get a small enough battery. You can get them from BMSBattery .
 

Hans Bontinck

Finding my (electric) wheels
Feb 12, 2015
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Hi Thanks!
Weight is more important than range for me. I do not mind if it maxes out at 15 mph. I'll pedal the extra 3 miles if i want to go faster :)

What is the difference between a S06s and s06p? I am asking this because BMSbattery offers bottle battery packs with the s06p but not with the s06s.

Secondly, is such a bottle battery waterproof?

Thanks!
 
D

Deleted member 4366

Guest
S06P is a square-wave controller and sensorless. It doesn't work very well with the Q-series motors.

The cylindrical bottle batteries are not very waterproof, especially the BMSB ones.
 
D

Deleted member 4366

Guest
That's the problem with a Brompton: Where to fit the battery. The only logical places, to me, are on the frame in front of the seat or in a bag behind the seat. unless you can make a custom battery, lipos would be high on my list of possibilities.

Your BMSB link doesn't work (for me).
 

Hans Bontinck

Finding my (electric) wheels
Feb 12, 2015
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THanks D!veh.
IMHO Lipos are rather expensive and last only approx. 400 charge cycles. Moreover, i've read that in order to preserve battery life, it is recommended to max. decharge until 80% of the capacity.
So, i really think i'd ideally prefer a 4 or 5 Ah lifepo4. As long as it gets me accross my daily trajectory (5-6 miles on a hilly road), i'm happy.

Where can i find good battery holders? Any suggestions?

PS. The link without brackets might work :) https://bmsbattery.com/ebike-battery/495-36v9ah-lifepo4-electric-bicycle-battery-pack-battery.html
 
D

Deleted member 4366

Guest
That battery is LiFePO4. Too big and heavy tor a Brompton. I wouold disregard everything you read about lipos. They'll last more than a year using them every day. By then, there'll probably be better batteries anyway. This 80% discharge is a load of ballcox. If it says 5Ah on the wrapping, that's what you get from them. If you want to try and get more cycles out of them by only using 80%, get 6Ah, then you won't notice the reduction, but you'll have 20% more weight. The only things you should consider for lipos is whether you have the knowledge to use them safely and whether you want to put up with the slightly more complicated charging procedure, which is not too bad for a small pack compared with a big pack that you need to break down each time you charge.
 

Hans Bontinck

Finding my (electric) wheels
Feb 12, 2015
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D

Deleted member 4366

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You need a minimum C rate of 5, so they're all OK.

The chargers are normally 6S, so 6S packs would be best. You can get 12S packs and chargers, but they will be much more expensive.
 

Hans Bontinck

Finding my (electric) wheels
Feb 12, 2015
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Hello all,
I've let some months pass, and will now go ahead and buy the kit with these http://www.hobbyking.com/hobbyking/...500mah_6S_25_50C_Lipo_Pack_EU_Warehouse_.html Lipo's.

But i am very confused on the charging situation.

The most comfortable would be to parallel "balance" charge 2 6s packs.
Which chargers do you recommend? I've read other configurations consisting of 2 chargers that are paralel connected.

I understand only a 12s charger can read the cells individually.

I've searched around, found detailed fool proof walktroughs for a 10s pack.

What chargers do you recommend? Which Balance board? What kind of connectors should i buy ? .
Thank you for helping me out.
best
 
Hello Hans,

If you are looking for a high-end charger you might want to check out the Cycle Satiator from ebike.ca.

pros
- suitable for all battery types
- profiles can be programmed via pc and stored
- highly customizable
- high quality

cons
- pretty expensive. but it should be the last charger you buy in a lifetime

Can be ordered directly from the manufacturer Grin Wheel Technologies (the founder Justin is awesome!) in Canada or from the company I work for, Ebike Solutions, in Germany.

We've brought a Brompton conversion kit to the market ourselves, and I have come to drive it regularly and developed a certain fondness for electrified Bromptons. Concerning the battery question, we often put custom made batteries in the Brompton-Mini-O-Bag in the front of the bike. Personally I like that because I can remove the expensive battery while parking the bike and I always have a place to put my lock when it's not in use. And the bike retains full foldability (that a word?). However, when folded, the combined weight of front motor and battery are a bit challenging, the bike tilts in one direction while being carried up stairs (cellar, train etc.).

I'd love it if you could post updates on how your conversion goes and how the driving experience is.

best
Paul