A few questions

[barod]

Hi, I posted earlier in the introduce yourself section, I'm looking to convert my Giant hybrid to help me with a 20 mile daily commute from Warrington to Manchester. I really like the sound of a Q128c with a 48v battery as mentioned in a number of other threads, but before I go ahead with any purchases could I have some views and advice please on the following:

1. What are the pros and cons of having the controller separate? I like the sound of the Panasonic 48v 11.6ah battery from BMS that comes with a controller built in – it strikes me as one less set of gubbins to have to mess about with! What's not to like?
   
   
2. The bike has an octalink BB rather than a square taper, what issues does that raise and how should I deal with them? Am I right in thinking it impacts the PAS setup?
   
   
3. The bike also has a 9 speed cassette on the back at the moment. From what I've read that should be OK with the Q128c, shouldn't it?
   
   
4. And finally, it's got hydraulic disc brakes. What's the best way of having a safety cutout with them please? Any suggestions for where to go for the necessary parts?

I've picked up that I'm likely to have to swap the current 160mm rotor for a 180mm. My plan is to buy the motor bare and get my friendly local mobile bike mechanic to build it into a wheel for me, so that I've got more confidence in the quality of the finished article. I guess I can get him to sort out the fit and alignment at the same time.

I look forward to hearing from you all.
Dorab

 

[Deleted member 4366]

4. you don't need brake cut-outs on that setup because the controller doesn't make the motor run on.
3. That'll be OK.
2. That'll be an exercise in creative problem solving. There's loads of solutions, but you can't just fix it and plug in.
1. Not really much difference. The included controllers always have too much cable, so you have to find a way to lose or hide it. That's not difficult. I prefer a separate controller because it's easier to change if a better one comes along, though I suppose you could always dig out the battery ones if you wanted. The battery is the same with or without the controller.

 

[Nealh]

1. Plug and play neat tidy compact fitting.
No leeway if replacement needed.
Dolphin type battery controller is small/compact so nigh on impossible to retro fit.

2. There are octalink pas systems available. Hollowtech /gxp type easier to work with.

3. Good to go.

4.Handy if you use a throttle
A sensor and magnet are quite easy to rig up if required,

 

[Benjahmin]

You mention a 48v , 11.6Ah battery. This gives you 556.8Wh. I've seen various estimates of Wh/mile consumption for an average rider of between 10 and 20 Wh/mile. I'm guessing you're quite fit so would be at the low end of this, so say 10Wh/mile, giving you a battery range of 55 miles - ish. Warrington to Manchester, quite hilly? Windy? Cycling against the wind after a long Fridays work, feeling a bit knackered !? Might want to consider a bit bigger battery, range anxiety is a horrible thing when you know you're on a 20Kg bike.

 

[barod]

Thanks to all you night owls for the quick and helpful responses.
I need to think some more about the battery power and choice between separate or integrated controller. I don't think of it as being particularly hilly between Warrington and Manchester, but then again I've yet to suss out my route! I'd be able to charge the battery during the day, so that would alleviate some of the range anxiety, but maybe a battery with a bit more oomph wouldn't be a bad idea - although with the gears on the bike I would probably still be able to trundle along without too much effort, albeit painfully slowly! If I was really too knackered for the ride then at least there would be an option to get on the train...
Holidays are coming, so the project will be on hold now until next month, but I'll no doubt be back for further advice once I get properly started.
Thanks again,
Dorab

 

[topographer]

Someone's already doing it:
http://www.pedelecs.co.uk/forum/threads/oxygen-scross-mtb-ongoing-review.28142/page-5#post-386864

 

[barod]

Someone's already doing it:
http://www.pedelecs.co.uk/forum/threads/oxygen-scross-mtb-ongoing-review.28142/page-5#post-386864

Hey, thanks for pointing that out to me. That's incredibly similar to what my journey's going to be, so I'll be interested to see what route he follows, particularly inside the M60. An early Strava run shows him following the A56, which I'd rather avoid - much happier keeping away from the cars if at all possible, it's better for all concerned

 

[barod]

Hi again,
After a respite for holidays I’m seriously back on the case with this, getting close to the point of ordering the kit. However I now have a dilemma over which motor to go for.
I had a trial run into Manchester on Saturday which went really well: the commuting route that I’d worked out seemed fine, and I was surprised and pleased to cover the 18 miles at an average of over 15mph. The return journey on another possible route wasn’t so quick, but still over 13mph even with frequent stops to check I was still on the right road (which I wasn’t always!)
Admittedly this was riding a faster bike than the hybrid I’m planning to convert, but I’m now reconsidering whether I need the power (and weight) of a Q128C if this is what I can achieve unassisted - although of course it would be different doing it day in, day out. Even so, should I be considering a Q100C instead?
I’ve done a ton of searching on these forums on the topic, but I can’t find anything that tells me what sort of speed I might be able to cruise at if I was running a Q100C 36V with a 48V battery and 17A controller or smaller (I appreciate I’d have to limit the current to below 15A?)
Ideally I’d like to be able to spin along at a little over 20 mph with a reasonable amount of pedalling effort (not expecting the motor to do all the work by any means – this is my daily workout, after all). It’s a pretty flat route, and I reckon the total weight of me, the bike and what I’m carrying will be around 90kg.
I’ve seen quite a few posts suggesting the Q100C as a lightweight (and more legal) alternative, but I’m not sure if this would be asking too much of it, even with my input? I’d be really grateful for views before I go ahead and pull the trigger.
Thanks for all the postings on this forum, it’s been a real goldmine for me. I don’t know how you folk find the time to reply so quickly and helpfully, in addition to everything else you must be doing.

 

[Deleted member 4366]

36 miles at 20 mph will require around 12 Ah at 48v. A battery like that would weigh around 3.5kg . The difference between A Q100 and a Q128 is about 1kg, so that will be the difference between a 6.5kg kit and a 7.5kg kit, or you can say that you'd have to pedal about 1% harder with the Q128 when going uphill using the same power and speed as the Q100. The Q128 is a lot more robust.

At 48v, a 14A controller would be sufficient for either motor. that's all I have and my bike can cruise effortlessly at 22 mph:
https://www.aliexpress.com/store/product/ebike-kits-LCD-display-with-controller-Big-discount/738588_1874826753.html?spm=2114.12010612.0.0.b15893akHuQvc

 

[Nealh]

,
I’ve seen quite a few posts suggesting the Q100C as a lightweight (and more legal) alternative, but I’m not sure if this would..

Q100 is no more less legal then Q128, both have a nom power rating of more then 250w.

 

[barod]

36 miles at 20 mph will require around 12 Ah at 48v. A battery like that would weigh around 3.5kg . The difference between A Q100 and a Q128 is about 1kg, so that will be the difference between a 6.5kg kit and a 7.5kg kit, or you can say that you'd have to pedal about 1% harder with the Q128 when going uphill using the same power and speed as the Q100. The Q128 is a lot more robust.

At 48v, a 14A controller would be sufficient for either motor. that's all I have and my bike can cruise effortlessly at 22 mph:
https://www.aliexpress.com/store/product/ebike-kits-LCD-display-with-controller-Big-discount/738588_1874826753.html?spm=2114.12010612.0.0.b15893akHuQvc

Thanks as always for the helpful advice. Given the hammer this is likely to be getting "robust" sounds good to me. So, Q128 it is then!
Thanks too for the link to the controller, that looks like a nice neat setup. Any suggestions about which PAS I should go for with this kit? I've just had the bike serviced and he's fitted a new Deore Hollowtech2, so I no longer have an octalink crank to worry about. Will the D12L fit with some customisation? It looks tidy if it can be installed

 

[Deleted member 4366]

To fit a PAS to a Shimano Hollowtech with 68mm BB, you need to increase the hole in the magnet disc to 25mm and flatten down the middle web to reduce the thickness, then you need to change the sensor from one side of the bracket to the other, which might mean drilling a couple of holes for the screws if it doesn't have mirror symmetry.

You then fit it to the left side after you remove both spacers from behind the bearing holders. The bracket goes behind the bearing holder and the disc goes between the bearing holder and crank arm. There's just enough thread left on the plastic cap to pull the crank together - maybe two threads.

Don't forget that the magnet disc arrows might be wrong when you fit it on the left side, so test which way it works before reassembling. don't get the dual hall sensor PAS because some of them are handed.

 

[barod]

I think I'm going to have a go at mounting the magnets on the RHS on the small chainring - that seems a lot less obtrusive than having the disc sitting proud of the crank on the left. From what I've read this should be possible, it's a question of how to fix them to the chainring and making sure they're (or the sensor is) the right way round?