Recommendation for girlfriend

[Arbol]

Since I have started exploring e-bikes, my girlfriend has asked me if I could add a kit to her bike:

She is going to use her bike only for her work trip: 9.2km one direction (and 9.2km back). She does not need to bike on the road (there are specific bike lanes). The trajectory is always uphill, with soft but non-negligible slopes (the return way is of course quite easy). She weights about 50kg. Lightness of the whole package is more important than sheer power.

She is going to leave the bike on the street. I have been thinking about pinheads for seat and wheels, and two Us.

The problem is electrification. The idea would be that she uses a front basket (she has one, even though it does not appear in the pic; in the pic, you can see the support for the basket), and once she arrives to work, she puts the battery inside the basket and takes it with her, leaving the bike without the battery.

As a consequence, both controller and motor should be relatively stealthy.

I have been thinking about those battery bottles with a controller inside. I guess those battery bottles can be extracted on a daily basis without suffering damage.

There is the possibility:

http://www.bmsbattery.com/36v/567-bottle-ebike-battery-controller.html

but I do not know the quality of the batteries. And d8veh argued the s06p does not work with a q100, and a s06s with halls would be difficult to install.

There is also from xofo:

http://www.xofomotor.com/display.asp?id=753

which apparently has "good" cells (samsung or panasonic). I could buy a xofo motor http://www.xofomotor.com/display.asp?id=781, which I guess is better than a q100 (but not 100% sure). But I do not know which controller is the one inside the bottle package, and if it is a good and safe controller.

Of course, another option would be to choose a nice case such as http://www.xofomotor.com/display.asp?id=796 but then I do not know where I would put the controller (but maybe somebody has a good idea where to put the controller, from looking at the picture, and this option becomes feasible).

Any ideas? Regarding:
1. Which controller: inside bottle, or outside
2. Which battery: bottle or nice case (I discard a frog since I have read they have some problems)
3. Which motor: q100, xofo or another one

 

[Deleted member 4366]

It wouldn't be practical to disconnect the controller whether it's in a bottle battery or not because there's too many connectors. Jerrysimon uses a big multipin connector on his Bromptons, but he has a very minimalistic setup, which means a sensorless motor and no PAS or brake sensors, which would leave thee throttle wires, three motor wires and two for the battery = 8 wires, 6 of which have to carry high current (15 amps).

If you use a front motor with the battery in a basket on the front,the steering will be a bit strange to say the least. You'd be better spreading the weight a bit.

At 50 kg, any motor should be OK, but to get the stealth you require will need a bit of imagination and inventiveness, Some kits provide a plastic box to put the controller in, which clamps to the seat-post.

 

[KirstinS]

I think OP meant the battery and basket would be removed on arrival at work

Not that it would mounted there when cycling

Could be wrong !

 

[KirstinS]

My controller is inside a normal plastic water bottle (cut open and tap end together again ) on a normal bottle holder

Adds an element if stealth IMHO

 

[Arbol]

I think OP meant the battery and basket would be removed on arrival at work

Not that it would mounted there when cycling

Could be wrong !

Yes, sorry if I was not explicit enough: if I chose the bottle (+controller), the bottle would be located on the top tube (usually bikes have two holes for a bottle, on the down tube; the bike has two holes for a bottle, but on the top tube).

My girlfriend would extract the bottle when she arrived to work, and she would put the bottle inside the basket, and she would take the basket with her. The bottle support (including the controller) would be left anchored on the bike.

 

[Arbol]

Some kits provide a plastic box to put the controller in, which clamps to the seat-post.

How do these kits clamp? With screws, or just straps? I ask for security reasons: with screws, I could be relatively confident it is unlikely somebody will start unscrewing the controller in the middle of the street. But if it were straps, a burglar could do it easily.

I guess that you are referring to something like:

http://www.bmsbattery.com/controller/365-ku63-controller-case.html

Does this work only for KU63/65, or also for s06p/s06s?

 

[KirstinS]

They are plastic brackets with screws

But I wouldn't worry - controller is 30 quid to replace and hard to remove with cutting off wires and connectors

Never heard of just a controller being stolen - what's the point. No resale value in a damaged bit of niche equipment that was only 30 quid to start with

Either the whole bike will go or the battery as they are the expensive and sellable bits

And you are going to remove the battery

Just get a decent lock is best you can do IMHO

 

[Deleted member 4366]

Another consideration is the rain. If the bike is left out all day in the rain, disaster will follow unless you take special precautions. Nothing that a few freezer bags and some rubber bands can't fix, but you need to seal the disc mount holes in the motor, ans stick some silicone up the wire exit, and make the wire exit downwards fir a drip loop.

It's a very tight squeeze to get the controller and the connectors in those plastic boxes. It's easier if you cut off some of the bigger connectors and solder direct. You normally have a connector at the motor, so you don't need them at the controller, and the large battery one can be moved nearer the battery. The two brakes can be spliced onto one connector, solat leaves one rake, throttle and PAS, which should fit. Cut off the connectors that you don't need like cruise, speed restrictor etc. The box supplied with the 8Fun kit is a bit bigger, so not such a problem, though it's still tight.

If you go to Xofo, they have a waterproof controller and harness. The controller clamps to the seatpost. MXUS have a similar system. Both Xofo and MXUS have their own factorys where they make the motors and other stuff, so you get a bit more support than the average Chinese factors.

http://www.mxusebikekit.com/shop_show.asp?cid=46
http://www.szxfmotor.com/ProductsAllZ5.asp?id=160&Str=KITS

 

[jackhandy]

I think you'll find it tricky to find anywhere to mount a bottle battery on that frame (in the photo) remembering you need room to latch the battery into place.
Your only option might be under the diagonal & it'll be very wet down there, as well as having the weight pulling down from the cradle.
You may have to consider a frog battery, which should be ok if she'll not be bunny-hopping big kerbs et al . But I see the seat's too low for that too.

 

[KirstinS]

I think you'll find it tricky to find anywhere to mount a bottle battery on that frame (in the photo) remembering you need room to latch the battery into place.
Your only option might be under the diagonal & it'll be very wet down there, as well as having the weight pulling down from the cradle.
You may have to consider a frog battery, which should be ok if she'll not be bunny-hopping big kerbs et al . But I see the seat's too low for that too.

Won't it fit on the top bar ? Looks like there are water bottle nuts there ?

 

[Arbol]

Won't it fit on the top bar ? Looks like there are water bottle nuts there ?

Exactly, there are water bottle nuts on the top bar. My doubt is whether the bottle nut closer to the seat tube is "too close" to the seat tube: the bike is small in size, and that bottle nut is at 9cm from the seat tube. Will the bottle+controller fit?

 

[Deleted member 4366]

I have these dimensions for the sideways opening bottle battery. if this one fits, so will all the other 36v ones, but it looks like a no for this one:

 

[Deleted member 4366]

What about a front Q100 kit with the battery and controller securely locked in a top-box like this. nobody would expect anything other than waterproofs in there. You could even bolt in a false bottom so that it's impossible to get at the battery without tools even id they could prise the box open:

http://www.ebay.co.uk/itm/M-Wave-Bicycle-Rear-Carrier-Top-Box-RRP-32-95-/191005294960?pt=UK_SportGoods_CyclAcces_RL&hash=item2c78cd8170

http://www.bmsbattery.com/ebike-kits/420-250w350w-q-85100sx-motor-e-bike-kit.html

http://www.bmsbattery.com/36v/183-36v-10ah-lithium-ion-electric-bicycle-battery-pack.html

http://www.ebay.co.uk/itm/SAKURA-BICYCLE-TOP-BOX-WITH-KEY-AND-MOUNTING-BRACKET-/151212151926?pt=UK_sportsleisure_cycling_bikeparts_SR&hash=item2334f25476

 

[Arbol]

Yes, d8veh, this is a solution I have been considering: add a rear basket (one of those top boxes would be too fancy for Barcelona burglars, but baskets are apparently ok, since many bikes left on the streets have baskets), cover it with black cloth, and put a false bottom, with the battery and the controller being hidden below the false bottom.

The basket could be something like:

http://www.bikester.es/basil-cento-canastilla-trasera-negro-265253.html

This is possibly the most flexible solution, and with the additional bonus the battery could be left at the bike when parked.

A problem I find is a rear basket requires a rear carrier. But my girlfriend's bike has only one hole at the seat stays (at the center of the seat stays) as opposed to the two (lateral) holes that can be used to attach most rear carriers:

Do you know if this hole can be used with rear carriers, or it has other functions, and a rear carrier cannot be attached to this bike? Maybe something like http://www.bikester.es/asista-carry-portabultos-para-bicicletas-negro-269427.html could work?

A second question: d8veh, you recommend a front q100 with the rear top box. Why not a rear q100 instead? I guess wiring is simpler in this way, and usually people say a rear motor rides better than a front motor.

 

[Deleted member 4366]

A rear motor is better, but you don't really want all the weight on the back. It'll be OK as long as you can get the battery close to the seat-post.

Racks should be no problem. Many use that hole for fixing.

 

[jackhandy]

What - on top of the top bar?
I didn't even consider that: With the seat set so low, I suspect the rider's quite small & might find it a tad obtrusive; But if that's the ony option...

 

[Arbol]

I have these dimensions for the sideways opening bottle battery. if this one fits, so will all the other 36v ones, but it looks like a no for this one:

The picture above gives the "normal fixing screw range" as 100mm, but I have measured the distance between the holes of the water bottle holder in my bike, and it is something like 70mm. Does this mean my bike cannot accept this kind of bottle? Or the guides of the bottle can be adjusted to any distance between the holes?

 

[Deleted member 4366]

The 100mm is a slot, so the screws can go anywhere in that range. You can drill the extrusion to extend that range a bit. The important dimensions are the 125mm from the end of the battery to the first possible fixing position, and then the next 205mm to the end of the battery.Bear in mind that you still need a bit of frame clearance to get the battery in and out. This is the sideways fitting battery. If you have the type that unclips vertical, you need good clearance at the top to get it out.

 

[Arbol]

In my girlfriend's bike, the fitting is not possible. In my bike, I believe it is possible.

I only can find this battery with controller at BMSbattery and at xofo. At xofo they have not replied to my email. At BMSbattery, there is no brand for the cells, so I assume they are low quality cells, so the max amperage of 15A accepted by the controller is probably not reached (it says 10A max amperage at the webpage, so I assume they are using a 10A BMS).

I tried to contact b-t-n.cn, but Kevin Fang very bluntly told me he was not going to service me since I was willing to buy only 1 piece.

BMSbattery has also the problem that apparently the controller inside the bottle is the S06P (even though they give also the option for the S06S in their webpage). And the Q100C apparently does not work too well with sensorless controllers.

So it seems the ideal solution would be a xofo battery (which I believe they allow to choose the brand of the cells, at least this is possible with their bigger boxes) and an XF-V(K). I have never heard complaints about this motor for running with a sensorless controller. Probably the motor is too big for such a battery (I would guess the effective power is not going to be more than with a Q100C, given that battery, but maybe I am wrong?) but it seems the least bad option.

Does anybody know how to efficiently contact xofo?

 

[Deleted member 4366]

Although I've recommended Xofo in the past, I've had a recent e-mail from him saying that he doesn't want to supply to non-trade customers.

10 amps max on the battery means 10 amps continuous max. Burst will be double, so that battery will be OK with a 15 amp controller.

That's a bit weird about Kevin Fang because he has an Aliexpress website where everything is qty1. I guess for some items, he has to buy in a minimum quantity.