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[m1santhrope]

hello, i have a 7 mile each way commute with a steep climb for the first mile on the way to work, so i have been looking into buying an ebike.

I already have a fully kitted out 29er with 35mm road tyres and naturally would rather convert it than have to sell it.

Please can you help me put together a shopping list of the items i need to buy including any specialist tools i will need to undertake the conversion.

I already have a rack so would prefer the battery located over the rear wheel.

The bottom bracket is 76mm wide.

Many thanks.View attachment 22010

 

[Deleted member 4366]

How fast do you want it to go. How far? How heavy are you? What sort of hills?

 

[DynatechFan]

I am converting a 26" wheel MTB for similar duties and went down the geared rear hub route with a kit from YSBattery on ebay - seems decent kit for the money, not built it up yet mind (though I did buy it on the recommendation of another poster on here who rates the kit)

 

[Deleted member 4366]

If you want the nicest electric bike experience, the Q128c with a KT sine wave controller (plus LCD and PAS) and a 48v battery is e-bike nirvana. There's lots of other nice kits that all do the job. The only things to avoid are controllers that don't have an LED/LCD control panel. Non-sinewave controlers make the motor coarser and noisier. Rear motors are safer and quieter than front ones, and generally give better handling and traction.

 

[h0ward]

d8veh,

I am intending to convert a 26" wheel bike using your recommended combination (36V Q128c motor & 48V battery), thanks.

What are the pros and cons of a 20A vs 17A (or other) controller, please?

I shall be commuting, 15 mile round trip, mostly flat, sometimes with a significant head wind, but no stops. I am reasonably fit, so really just need pedal assistance, generally to around 20 mph. I am more interested in battery range and longevity than all out speed, whilst cutting a few minutes off my present journey time. Occasionally I would like to travel further, on more varied (hilly) terrain, and sometimes a little faster, all up weight 90kg. I don't think that I shall need to use the full 20A at 48V, so would a 17A (or even lower-rated) controller be more suitable,? In essence I guess I want the system optimised for efficiency and reliability, if poss.

I am happy with your recommended motor, more robust, and powerful than the Q100, if a little heavier, I understand? Battery I shall source in UK due, in part to the shipping costs from China. The Eclipse units at 48V 12Ah look good, is the standard/supplied charger ok in your opinion, or worth an upgrade (expensive though)? Torque arms from BMS too. I have a rim, and know about spoke length and wheel building.

OP, sorry if I am hi-jacking your post, but my requirements seem similar to yours (despite the smaller wheels), D8veh can probably advise if the 36V or 48V version of the motor goes better with the 29er wheels. I too am keen to convert rather than buy finished bike (more fun).

Sorry if I am repeating questions already answered, but I couldn't find them. As a newbie, I have read quite a few posts here (and elsewhere), and have found the info invaluable and enlightening, thanks to all!

 

[BornAgainCyclist]

If you have a look at the search results for Q128C there is a wealth of info about sourcing various components from different places and what you would need to do in each case with pics of completed conversions too which really helped me. I think there is someone else who is doing exactly what you are thinking in one of the threads. The BMS battery with controller and waterproof connectors with the Q128C really was plug and play. The wheel was self-laced but dished by an LBS and the biggest challenge was getting the PAS one which needed some grinding to fit.

 

[Deleted member 4366]

d8veh,

I am intending to convert a 26" wheel bike using your recommended combination (36V Q128c motor & 48V battery), thanks.

What are the pros and cons of a 20A vs 17A (or other) controller, please?

I shall be commuting, 15 mile round trip, mostly flat, sometimes with a significant head wind, but no stops. I am reasonably fit, so really just need pedal assistance, generally to around 20 mph. I am more interested in battery range and longevity than all out speed, whilst cutting a few minutes off my present journey time. Occasionally I would like to travel further, on more varied (hilly) terrain, and sometimes a little faster, all up weight 90kg. I don't think that I shall need to use the full 20A at 48V, so would a 17A (or even lower-rated) controller be more suitable,? In essence I guess I want the system optimised for efficiency and reliability, if poss.

I am happy with your recommended motor, more robust, and powerful than the Q100, if a little heavier, I understand? Battery I shall source in UK due, in part to the shipping costs from China. The Eclipse units at 48V 12Ah look good, is the standard/supplied charger ok in your opinion, or worth an upgrade (expensive though)? Torque arms from BMS too. I have a rim, and know about spoke length and wheel building.

OP, sorry if I am hi-jacking your post, but my requirements seem similar to yours (despite the smaller wheels), D8veh can probably advise if the 36V or 48V version of the motor goes better with the 29er wheels. I too am keen to convert rather than buy finished bike (more fun).

Sorry if I am repeating questions already answered, but I couldn't find them. As a newbie, I have read quite a few posts here (and elsewhere), and have found the info invaluable and enlightening, thanks to all!

That setup seems to be perfect with 26" wheels. I guess that it wouldn't be too bad with a 29" wheel, but if you're not bothered about speed, the 48v 201 rpm version will give about 20 mph with better efficiency than the faster setup.

The current is a difficult one. I only have a 14A controller, which gives all the power I need for our steep hills and my weight of 80kg. With the PAS, the current is limited at each level, so the maximum current makes little difference. If you have a high current controller, you can always turn it down, but with a low one, you can't turn it up. The 20A controller would therefore be the logical choice, except that you might get lower current and longer range on level 1 of the 14A one. You have to decide what you want.

Reliability isn't really an issue, except that higher currents put a bit more strain on the battery when you use them.

 

[h0ward]

Thanks, BornAgainCyclist, and d8veh, and m1santhrope,

Detailed answers, great! The BMS battery with integrated controller looks really neat, especially with the waterproof connector, I reckon a very good solution. Only downside is shipping cost, probably not more than UK all-in, unless it develops a fault and needs returning. BMS seem to have a good reputation.

Still undecided exactly which motor to choose, as I am quite light I favour the 36V (with 48V battery). I shall make an effort to assess my present speed, and work from that: 20+ mph (36V motor & 26" wheel) would be more than adequate, but 19mph (48V) a tad slow, but closer to legal. Thanks for the clarification regarding controller choice, all makes sense now. Drawing 17A from the battery at max PAS setting might be a good compromise for me (headroom), who knows, I may lend the bike out occasionally. I suspect that I'll be happy with any of the combinations in reality, in any case a different controller later would be cheap enough.

I did read some of the other Q128 threads. I am more than happy that I have enough info now. I hope that the answers might benefit m1santhrope (OP), and others as well. If/when complete, I'll post some details. Great forum!!!