Buy list: opinions are welcome v2.0

[Arbol]

A few days ago, I opened a thread, "Buy list: opinions are welcome":

http://www.pedelecs.co.uk/forum/threads/buy-list-opinions-are-welcome.17190/#post-211792

One of the comments rang a bell on me: a light weight bike will not be as nimble as before, when electrified. I also recall having read that d8veh said it is better to have different bikes for different usages. Despite the fact that originally I wanted a "one size fits all" bike, I now think probably is best to have at least two:

One, my current Rockrider 8.1, leave it as it is. In fact, I have a love affair with her, yesterday I was more than 2 hours pushing my limits in a nice environment, and she reacted every time as she had to. It was one of my best bike experiences ever. I definitely do not want to change her.

Ok, now I need a vehicle for urban usage. I have been talking with a guy here in Barcelona who has built a few single speeds with q100 and ku63. He has a good taste with the components, and he puts the cables inside the frame, etc. I once tested an electrified bike he had built, and it worked pretty well.

This guy has suggested something like this (the blue one):

http://www.barcelonetabikes.com/page/6

But with aero wheels (a bit wider), black spokes, a q100 motor (I prefer a q100h 260rpm, both because of the increased torque and being black) and a ku63. Only throttle. Rear dropout is 120mm, but he says he can take out the extremes of the q100, which leads from 135mm to 128mm, and the steel frame could be widened a bit (he has done that before).

I would add one of the new high c-rate BMSbattery 36v10Ah batteries.

I am doubtful if I could use a ku93 instead. I believe the ku93 is 22A max. 36V*22A is 792W. I recall d8veh said he used a q100 with 12s (44V) at 17A, which is 748W. I do not know if this is too much, or if it would be better to stick with the ku63. Also, the ku93 is apparently huge, as big as the ku123, which is a drawback.

The guy has told me this configuration could easily climb the moderate hills I will usually have, so there is no need for a BPM and bigger battery.

I would put the battery inside one of these panniers:

http://www.planetx.co.uk/i/q/BASMGBLP/selle-monte-grappa-bauletto-leatherette-pannier-bags

(when riding, I would put the chain in the other pannier, which would stabilize the bike laterally). Of course, I will sew something above to look like there is nothing on the base of the pannier, in case somebody opens it.

I want to put the pannier on the seat post rack d8veh recommended. The only issue is how to add some struts to the frame of the bike above, which can be fixed to the rack too, in order to make everything stronger.

The final issue is where to put the controller: either inside the opposite pannier of the battery, on top of the shelf of the rack (covered by the panniers) or below the shelf of the rack.

Mmm decisions decisions decisions.

What do you think about this build?

 

[Geebee]

I love the super light assist option as the bike still feels the same, ground handling is still easy, smaller battery pack.
I found a Tongin more than enough when healthy, it was 180w rated and max power was 24v at 12 amps it was enough to make 15% grade easy at low speeds as opposed to almost killing you after a long ride.

 

[jerrysimon]

The only other alternative is to try the smaller Keyde motor. At 1.5kg and 90mm diameter it is not much larger than a dynamo in the front wheel. Depends how hilly it is where you are as it peaks at about 300W.

Here is the Tongxin and Keyde side by side.

Another advantage of the larger Tongxin is its virtually silent when engaged. The Keyde is quiet but not silent. I have a black Keyde but I am not sure if the Tongxins come in black.I am about to try it in my next project a lightweight 531 framed city commuter.

Jerry

 

[Geebee]

You could screw the controller upside down under the rack base.
The drop outs are nice and flat so a hole each side for the rack stays.
Front of the rack could be a flat plate from the mudgaurd screw hole to the front of the rack base.
The Q100b sounds good, a bit more grunt as the bike is single speed.

 

[Arbol]

Jerry, I believe there is not much advantage with the Keyde / Tongxin for my build, since I do not have specific requirements for front dropout size.

If I understand correctly, a q100h is more powerful than these motors, and just slightly heavier. As a consequence, if a q100h fits, it is "better" than the Keyde / Tongxin.

Also, I want a throttle, and I believe a Keyde does not accept a throttle.

 

[Arbol]

You could screw the controller upside down under the rack base.
The drop outs are nice and flat so a hole each side for the rack stays.
Front of the rack could be a flat plate from the mudgaurd screw hole to the front of the rack base.
The Q100b sounds good, a bit more grunt as the bike is single speed.

In fact, I have found a shop in Barcelona making hard plastic boxes of different shapes and sizes.

I could try to build a box to be screwed to the water bottle holes of the seat tube, in order to fit the battery and the KU63. The battery is about 25cmx9cmx7cm, and the controller is slightly less than 10cm long (and the other dimensions are narrower than the battery). So, if the seat tube is longer than 35cm (there are water bottles of almost 9cm, so 9cm wide should not be a problem), I believe I could fit a box encasing both the battery and the controller.

I have to see if this could work, but probably it would be better for weight distribution to have the battery and controller inside the triangle rather than outside, at the rear rack. d8veh insists a lot on the importance of weight location. Of course, also weight would be lower, without a rear rack and a pannier (hard plastic is very light).

 

[Arbol]

Editing the previous post:

I believe it is unlikely the seat post is long enough to allow a 25cm long, 9cmx7cm width battery, and a 9.7cm controller such as the KU63 in vertical position.

So, the controller should be put "flat". But then there is the problem the KU63 is 9.7cm long in a flat position, and since the connections also take some space, it could be the length of the KU63 widely surpasses the 10cm mark, which I believe is mostly the limit in width inside the triangle.

Funnily, the S06S/S06P are shorter, 8.6cm in length. So, 8.6cm plus the cables would possibly be a bit more than 9cm, which would fit with the 9cm width of the battery. Then, it could make sense to make the fully fledge throttle + PAS + ebrakes + LCD.

Does anybody know how much length there is in the combination of a S06S plus the cables, until one can start "turning" the cables?

 

[Deleted member 4366]

I don't think that the Q100H makes any more torque than the standard one, but it has a higher speed. The torque of the standard one starts to fall off at about 12 mph as the motor approaches its top speed, while as the Q100h can hold on toits torque up to a higher speed. If you compare the torque at 8mph, they're probably the same, but by 12mph, the Q100h starts to creep ahead. At 18mph the standard Q100 is making zero torque, while as the Q100H is still producing something meaningful.

In summary, there's no torque difference, just speed difference.

These results are when running at the same current. I don't know if the Q100H has more capability to run at a higher current, which will produce more torque. The standard Q100 gives quite good torque and 20% extra speed when you run it at 44v. It would therefore be interesting to see how the Q100H runs at 20 amps and 36v, or it might make a nice high-speed motor for a light-weight bike at 44v.

None of these diminutive motors are going to be converted to torque monsters by feeding them loads of power, so don't think that they'll be dragging 100kg riders up 15% hills without pedalling.

 

[jerrysimon]

Also, I want a throttle, and I believe a Keyde does not accept a throttle.

It does if you use a third party programmable controller

Jerry

 

[patpatbut]

Editing the previous post:

I believe it is unlikely the seat post is long enough to allow a 25cm long, 9cmx7cm width battery, and a 9.7cm controller such as the KU63 in vertical position.

So, the controller should be put "flat". But then there is the problem the KU63 is 9.7cm long in a flat position, and since the connections also take some space, it could be the length of the KU63 widely surpasses the 10cm mark, which I believe is mostly the limit in width inside the triangle.

Funnily, the S06S/S06P are shorter, 8.6cm in length. So, 8.6cm plus the cables would possibly be a bit more than 9cm, which would fit with the 9cm width of the battery. Then, it could make sense to make the fully fledge throttle + PAS + ebrakes + LCD.

Does anybody know how much length there is in the combination of a S06S plus the cables, until one can start "turning" the cables?

I have S06S controller and I am able to fit all the connectors (including hall) and cables in the small controller case from BMSbattery. Yes it is very busy and you need to press it hard to close the case but it is dorable.

The main part is to replace most of the connectors with JST one. You can get it cheap on ebay.

Pat

 

[Arbol]

Why do you need to replace most of the connectors?