Seeking good advice for e-roadbike

[francoisr]

Hi group,

I'm trying to put together a bike for my commute. There's a lot of wizdom in the forum that I'd love to learn from.

Last summer I rode rear wheel 2806 9C, 36Vx10Ah NiCad battery pack and the Cycle Analyst mounted on an old, cheap mountain bike, 26" wheel. All but the bike coming from ebikes.ca. I loved the experience. I used it for my 20 miles, mostly flat commute. With hard pedaling, I could maintain 43 km/h (27mph), reaching the V/RPM limit of the motor( 9C-2806 / 36V). The 36Vx10Ah pack was too little for full throttle all the time so I used the CA to limit the Amps to 10A which gave me power for the whole 20 miles. I charged the battery on both ends of the commute.

My dislikes: bike was a bit heavy overall, rim brakes were on the weak side, I would have liked a little more top speed to cut time down to 1h, need to hold the half throttle all the time, bad aerodynamics.

Having learnt from last year I'm considering getting equipped with a recent but used road bike (with curved handlebars) for lighter weight, for the choice of riding position and the better aerodynamics. What I'm not after is high torque or acceleration: I'm willing to trade off torque and acceleration for greater top speed with hard pedaling.

I want to keep my budget under $1000 for the bike, kit & battery. Here's the setup I'm considering:
* a recent, used 700c road bike with curved handlebar for under $500.
* 500W Cute 128SX front wheel motor & kit.
* 48V x 10Ah LiFePO4 battery.
I'm considering a basic kit from BMS Battery. Either Sensor or Sensorless.
Overvolting from 36V to 48V would boost my no-load speed to +30MPH which I should be able to reach with hard pedaling.

My question or concerns regard the throttle, the brakes and the mounting on curved handlebars . The BMSBattery kit and most kits I've found as well as individual part target hybrid or mountain bike with straight handle bars.
* Full grip throttle do not fit on curved handlebars.
* Thumb Throttles that must be held all the time are not compatible with the 2 riding positions.
* Brake levers with cut-off switch not design for curved handlebars.

Crystalyte has a Cruise Control, the Cycle Analyst now has a similar feature too which kicks after 8 secs of holding the throttle but I need some cutoff feature.
Would a pedelec/PAS do the trick? Stop pedaling = stop powering? I have no experience with those. PAS are on/off, not proportional, right? So with a CruiseControl instead of a throttle, resuming pedaling from a stop would immediately power the motor at the % of power preset in the Cruise Control. That seems to be a acceptable setup.

Bottomline, can a PAS effectively play the same role as cut-off brakes?

Are there cut-off switches that fit the brake cable (vs brake levels). I could imagine a brake cutoff switch that would install on the wheel end on the cable, not on the level but I haven't seen those on the market, does that exist?

I'll choose a bike with non-carbon forks. Do I need torque arms with this 500W motor? Does that change if I get a 15Amps controller or limit the current to 10 Amps?

Any other comments on the kit or combo I'm putting to together to electrify a road bike are welcome.

Regards,

 

[FMB42]

I, myself, would consider using something other than "drop" (i.e. "curved") handle bars (especially on a front drive setup). I say this for a number of reasons (i.e. throttle and/or brake lever mounting problems, etc, etc, that seem to be common with drop handle bars).

Have you considered using a "clubman" style motorcycle handle bar design (as show in the link below)?

http://www.motorcycle-superstore.com/1/4/68/4917/ITEM/Bikemaster-Clubman-Handlebar.aspx?SiteID=SLI|Handlebars&WT.MC_ID=10010

These "clubman" bars might allow you to mount the throttle and brake levers while still providing some of the lowered riding position you desire. However, clubman bars would require the use of a "removable faceplate handle bar clamp" rather the old style "pinch handle bar clamp".

Here's a link the describes the two different stem types:

http://www.brightspoke.com/c/understanding/stems.html

 

[docnjoj]

Drop bar throttle mounting.

http://endless-sphere.com/forums/viewtopic.php?f=3&t=25334

otherDoc

 

[dogman dan]

Just my opinion, but you are heading up another road with that setup. It will take you to a nice place, but not where you want to be. (faster)

I'd keep the motor, but run it on 18s lipo. Use a Lyens 12 fet controller, but lower the amps to about 30. The bike needs to be built to carry some weight and take a pounding. For most of us, that's a Full suspension MTB.

All this will cost a lot, but you can start out by running 12s lipo on your existing bike, then upgrade to the same motor with disk mount on another bike as funds allow. Just switching to 50v fully charged will help a lot, and may end up being all you need.

Your biggest problem is the lame battery. Even just buying a 48v 15 ah pingbattery would give you the 30 mph and the range. Whether lipo or lifepo4, you need a bigger battery so you can run hard all the way.

 

[hillzofvalp]

What kind of 700c road bike is it? Age? steel/aluminum? type of fork? The reason I ask is that I am trying to convert a road bike as well with a mac motor from cell man (haven't bought it yet). I would like to see what other people are doing, and how safe they think it is on their given frame.

 

[dogman dan]

With the right mounting hardware, Alu rear dropouts should be fine. I'd stay away from carbon front forks though. Fit is the big issue, those bikes always have a cup on the dropout to contain a QR wheel. So get the c washers from Ebikes -ca.

I wasn't saying it's a bad idea, just not the way to go for a 30 mph 20 mile blast. Perfect for 15-20 mph, hypermiling, running on just pedals when possible. A different kind of ride than what the op seems to want.

 

[Uncle Ron]

Hi group,

I'm trying to put together a bike for my commute. There's a lot of wizdom in the forum that I'd love to learn from.

* Thumb Throttles that must be held all the time are not compatible with the 2 riding positions.
* Brake levers with cut-off switch not design for curved handlebars.

Crystalyte has a Cruise Control, the Cycle Analyst now has a similar feature too which kicks after 8 secs of holding the throttle but I need some cutoff feature.
Would a pedelec/PAS do the trick? Stop pedaling = stop powering? I have no experience with those. PAS are on/off, not proportional, right? So with a CruiseControl instead of a throttle, resuming pedaling from a stop would immediately power the motor at the % of power preset in the Cruise Control. That seems to be a acceptable setup.

Bottomline, can a PAS effectively play the same role as cut-off brakes?

francoisr,

You're getting a lotta good advice here and I'll only speak to my direct experience on a small part of your task.

I truly love the cruise control built into the controller of my Amped Bikes kit. It's one of the main things that makes e-triking a joy and I use it all the time even in heavily stop and go city biking. A thumb throttle without cruise is a medical issue waiting to happen, while a thumb throttle with cruise is a joy and superior for on road cycling, IMO.

I suspect that you are over thinking this with the PAS thingy. I'm not sure how it would work with the cycle analyst, but other iterations of cruise control are easily cut off by flicking the thumb throttle slightly as well as just touching the brake levers for cut off.

 

[LegendLength]

I'd keep the motor, but run it on 18s lipo.

I'd also recommend lipo because it will suit both your bike and the Cute motor which are both very light.

 

[dogman dan]

Yeah, once commited to a really light setup, lipo is just about the only way to go. But ride length will suffer unless you carry a lot of it, or pedal with motor off a lot.

Here's an idea for the OP. Build your light road bike, but for now, run it on the battery you have. Keep the original bike, and use it when you want more speed.

Later, as funds allow, start buying lipo. You'll love the old bike if you get a new controller, like a 120v one, and run a small pack of lipo on it.

Similar to this. http://endless-sphere.com/forums/viewtopic.php?f=6&t=25167

At that point you have two bikes. One that runs 12s 10 ah lipo with the light bike, and can hypermile quite a ways. The other is a 24 s 5 ah drag racer you'll enjoy for sure! All by buying just 4 6s lipo packs and a charger.