Electric Assist Motors; some questions

Per ¡Jones:
The tricycle on which it will be used weighs in at around 35 lb or so
dry. OTOH, the rider is handicapped and not known for coordination
and dexterity... I would prefer one that wouldn't engage from a stop.

I see a safety issue there.

These things are 98% Chinese-made and quality/reliability is what you
would expect.

I've had my own throttle jam several times, but I know what to do when
it happens.

The person in the situation you describe could be killed or seriously
injured if a stuck throttle threw them out into traffic, for instance.

In fact somebody I knew saw their very young niece go through a plate
glass window a few years ago: she was riding a 4-wheeler that nobody had
any business letting her ride... In that case, I don't think the
throttle jammed - but she got confused with the throttle...
--
Pete Cresswell

On Tuesday, November 4, 2014 8:50:36 PM UTC, Lou Holtman wrote:
User Bp wrote:
Andre Jute wrote:
throttle, and DIY midmotors are in their current stage of
development strictly for experts and masochists.


There's a grain of truth in that statement, but I would not discount
mid-drives if you have some space and know-how. I fitted an EcoSpeed
mid drive to an old Schwinn Town & Country trike for my 97 year old
father, it worked very well.

The only thing masochistic was fitting the mid-drive into the very small
amount of space available. With a longer frame, which I think the OP has,
it would not be hard. Having a separate wheel to drive strikes me as a
very mixed bag: Very simple drive train, but if geared for steep hills
might have some wierd behavior on extremely steep hills and slippery
surfaces.


The components were bought from http://www.ecospeed.com/
Battery pack was from http://www.batteryspace.com

Hope this helps,

bob prohaska

Geez. Walk in any bikeshop in the Netherlands and you can buy them ready to
go:
http://www.koga.com/nl/fietsen/elekt...va.htm?frame=H
This is just an example. I believe 50% of the new bikes sold is electric
assisted here. Unbelievable succes story over here

--
Lou

Yup, and the motor in that Koga you hold up as an exemplar perfectly illustrates my point. For those who don't know, the Bosch motor in the Koga and a number of other European commuter bikes is currently the best electric motor for (commuter) bicycles anywhere in the world. However:

1. It is OEM only. As far as I know, there is no consumer availability. Even if he should want one, Jones can't get one. Neither can anyone else. (Presumably there is some second-hand availability for the handyman and the masochist and the daydreamer.)

2. At Lou's URL take a good look at the bike. That's a specially built frame. So even if Jones can source a Bosch (and all the peripherals), he'd have to perform grimly serious surgery on his wife's bike to fit the motor.

Here's an available mid-motor, which has none of the disadvantages of all the others so far suggested, and which could, if nothing goes wrong (not necessarily a likely event), be a bolt-in installation as simple as front drive hub motor:
http://www.bmsbattery.com/central-mo...ral-motor.html
Again, as in the hub motor kit I suggested, this is a complete kit, a bolt-in job, with nothing for Jones to manufacture or source elsewhere, except the battery which he can buy at the same place
http://www.bmsbattery.com/36v/683-bo...e-battery.html
to avoid doubling up on delivery charges. This kit fits in the bottom bracket shell. It is however likely to be a more fraught installation, and in action it is less controllable and pleasant than the front hub motor, because a certain coordination of throttle with the driven rear wheel's gear cluster is required, whereas the front hub motor kit I prefer is indifferent to throttle position at gear changes. I spent several weeks of my spare time looking into a central motor and decided to wait for the next iteration, which most likely will have some kind of torque management to soften gear changes. One thing was firmly fixed in my mind though after my survey of the midmotor field: the Bosch is the best but it impossible for the aftermarket because it requires a custom frame that cannot ever be repurposed, and the second best central motor is the Bafang in my URL above, which, though a bit rough at the edges, leaves the rest for dead as crude and unsophisticated (motors bolted on top of frame members, extra transfer chains and gears, Jesus, how gross can even techies get?).

Jones, if you still haven't given up: Your wife is in no great danger from a 250W motor (even the high-torque one I've suggested) even if operated only on throttle rather than "automatically" as a pedelec. (As I explained elsewhere, she can't operate her bike as a pedelec because that reduces the motor's input just when she'll need it most; you may have to install the pedelec bits purely for legal reasons but the better kits have a convenient switch between throttle and pedelec operation.) Today I tried my bike on the motor from a standstill. My Utopia isn't as heavy as it looks (it is built with custom-designed and -drawn Columbus tubes -- the clowns on RBT who claim it is heavy are talking through their arses, as usual) but fully loaded with tools, battery, water, sketchbook and paintbox, with leather luggage to carry it all, it is no carbonweight either because it is designed to survive, and triumph over multiple circumnavigations. I had no problem getting the bike to run up to a slow walking speed on the throttle without me aboard, and with me aboard there was a significant hesitation before the front tyre started rolling. A stuck throttle is possible but no really a great problem, because the impulse is to hit the brake, and then the motor cuts out -- a proper installation kit, as in the setup I gave you two sources for, includes brake handles you fit that cut out the motor under braking, regardless of throttle position. I also tried, with me aboard, to make the bike do something dangerous under careless handling of the throttle, and I don't quite see how anything serious is going to happen though, if the lady were my wife, I wouldn't conduct practice rides in heavy traffic, because shooting out into traffic is the one scenario with a possibly unfortunate ending. For the rest, especially on a tricycle, I suppose one could bump a wall or a tree, but that's about the extent of it.

Another thing. You said something about a walking pace up hills. That is exactly what you buy and fit a motor to avoid! If a walking pace is good enough, all you have to do is give her better gears, and she can pedal ever slower. What the motor does, the way I and every experienced cyclist I know with a motor use it, is to use the motor to fill up hills so that speed is not broken too badly, or to keep up to a safe speed in traffic, or to carry groceries that get a bit heavy for aging legs and hearts.

There is something else you should grasp. The motor and battery will add at least 10kg to the weight of the bike. When the battery is dead, that's entirely dead weight, to be pedaled along. But you can't just buy a humongous battery, because battery weight increases linearly with capacity. So you should choose the battery to serve for the longest ride and the expected fraction of use on the ride. Fortunately, the good LIPO batteries that BMS sell (the ones with the Panasonic cells) are amazingly capable. I have only 8.8Ah, and in rides of up to 20 miles I have never used up more than 50% of the battery capacity even in very hilly countryside. I think Pete Cresswell uses an even smaller battery to save weight, but I don't care about weight because I ride for exercise not speed. I can't make a specific suggestion because I don't know how far you ride, or how much your wife will use the motor, but I seem to remember that Pete quoted a Ah per miile rule of thumb. It might be worth asking him.

Andre Jute

On Wed, 05 Nov 2014 11:01:31 -0500, "(PeteCresswell)"
wrote:

Per ¡Jones:
The tricycle on which it will be used weighs in at around 35 lb or so
dry. OTOH, the rider is handicapped and not known for coordination
and dexterity... I would prefer one that wouldn't engage from a stop.

I see a safety issue there.

These things are 98% Chinese-made and quality/reliability is what you
would expect.

I've had my own throttle jam several times, but I know what to do when
it happens.

The person in the situation you describe could be killed or seriously
injured if a stuck throttle threw them out into traffic, for instance.

Just touch the brake and the motor shuts off. Some can be programmed
that they will not restart untill the throttle is closed. That makes
them pretty well fail-proof and idiot proof.

In fact somebody I knew saw their very young niece go through a plate
glass window a few years ago: she was riding a 4-wheeler that nobody had
any business letting her ride... In that case, I don't think the
throttle jammed - but she got confused with the throttle...