Brushless Geared hubmotors: BIG list & details

[Reid Welch]

Gears: planetary gears are lossy compared against direct drive.

Plastic gears have been made since 1920, at least.
These were popular aftermarket replacements for the generally-noisy Model T's helical-cut half-speed gear
for the valve operation. It ran from a vanadium steel gear pressed and keyed to the crankshaft, and was usually failsafe, though sometimes the spokes of the cast iron timing gear would break (very rarely).

Customers who wanted silence purchased aftermarket gears made not of metal, but of linen cloth composite: linen, the strongest fabric, laminated, dozens of layers, in phenolic resin. These ran dead quiet and were strong,
IF made by a reputable manufacturer. I had but never used a Westinghouse brand Ford timing gear.
It was a beautiful thing and would have served well.

---
got in to grab the exact url becuase I'm too ignorant to do it otherwise.
NO edits whatsoever. submit, see your post, it says. otay.

Now, today we have super-tough plastics suitable for the extreme punishment of direct-crank driven ICE engines.

For instance, the Honda generators use a molded, not laminated, tough plastic that does not soften in hot, hot engine oil.
Nylon, if that's what these geared motors use, is relatively soft and gets very soft when heated at all.

By actual timed report (engine hour meter), one RV user of a Honda EU2000 got fully 10,000 hours service from his plastic timing gear.
I cannot overemphasize how much more severe this service is, than a three-gear planetary, smooth rotation motor:

the IC engine using a direct drive timing gear slams and whams the gear teeth with every explosive impulse.
Yet, today, there ARE plastic composite gears that WOULD last nearly forever in a geared hub motor.

Are the Chinese manufacturers green with inexperience? Laminated timing gears of old often ran for tens of thousands of miles, or for decades, without failure. And their service life was like, a hundred times rougher than that seen by three-gear planetary smooth rotation low power electric motors.

"Nylon", if that's what they are all using, is Three Stooges material for this sort of duty;
it may work for a long time; then again: shock and lugging and over-powering and heat may ruin them.

IMO, there is no desirable reason to have a steel planet gear in one of these motors: sure, it will work,
but why? It is not 1908 anymore and noise of steel spur gears is often considerable, and soft steel on soft steel, if not run in oil, may no wear well at all. Grease is a poor lubricant for fast running gears,
but is often the only lubricant that'll stay put.

Better gears are in our future. They will be plastic. Find out what Honda uses and use that exact brand of plastic, and test the material til failure.

My opinions,
r.

__________

url grab, not an edit.

[Mark_A_W]

"Gears: planetary gears are lossy compared against direct drive."

You are kidding me right?


Direct Drive motors are bogged down in inefficient low RPMs for ~4x longer than Geared motors.


A Bafang on 48v 10A will accelerate as hard as my big DD motor on 60v 30A with 1/4 the power used...we just tested them. I have more top end, but the bafang is amazing for such a small lightweight motor. My motor doesn't light up till ~25kmh, then it pulls till ~45kmh. The bafang pulls from standstill till about 40kmh.


Yes there is a RPM, which if you just *sat* there forever, the DD motor is more efficient. But in the real world we stop and start.

[Reid Welch]

"Gears: planetary gears are lossy compared against direct drive."

You are kidding me right?

No. Learn more about gears and their inherent losses.
I spoke of planetary spur gearing: the most inefficient, nearly, of all gears other than bevel gears.

Direct Drive motors are bogged down in inefficient low RPMs for ~4x longer than Geared motors.

Absolutely true; no argument here.

A Bafang on 48v 10A will accelerate as hard as my big DD motor on 60v 30A with 1/4 the power used...we just tested them. I have more top end, but the bafang is amazing for such a small lightweight motor. My motor doesn't light up till ~25kmh, then it pulls till ~45kmh. The bafang pulls from standstill till about 40kmh.

Yes, because the tiny motor itself is spinning at a high and efficient rpm, as you well know.

Yes there is a RPM, which if you just *sat* there forever, the DD motor is more efficient. But in the real world we stop and start.

In my real world I drive on level ground at 20mph,
often without stops, for many miles at a time (28 miles the other night). IF I were going cross country,
a direct drive motor would beat your geared hub motor for electrical and =mechanical= efficiency.

That said, I am a big, big fan of geared hub motors. That's why I bought one myself: an eZee.
It pulls from a standing start, it is quiet, it is efficient enough at rated speed to draw only 20Wh/m,
which is probably pretty close to, but not fully equal to that of a direct drive motor of ideal winding characteristic for the speed and load it works at, at steady, high, road speed..

Most of my reply is in red font today because I just had a tooth pulled twenty minutes ago.
I'm bleedin', I tell you, bleeding! Ha ha! I'm a very EFFICIENT bleeder.

And boy, do I know planetary transmissions, from Boston pencil sharpeners to the Model T and other early auto transmissions.

Geared hub motors are the bees knees for me: small, efficent enough, torquey...
...are we in any disagreement, other than for your first, aggressively rude statement?

I love you just the same and will make you a "friend" in my profile list of effers.

Kind regards,
yr pal,
Reid

[Mark_A_W]

"Gears: planetary gears are lossy compared against direct drive."

You are kidding me right?

[color=#FF0000]No. Learn more about gears and their inherent losses.
I spoke of planetary spur gearing: the most inefficient, nearly, of all gears other than bevel gears.

I am a Mechanical Engineer Reid. I know a reasonable amount about gears.

[Reid Welch]

Mark is now a "friend" because I have never met an Aussie I could not like.
They rule and they are all plain, honest speakers. Kudos for the man.

I remember Dom Harvey, no longer active here, and Aussie Jester, and others:
all first class blokes who would give you their last bottle of beer along with a smile.
Wonderful people, Australians.
Too bad most of them come from former, criminal stockades

Yr pal, Puck...rhymes with....

[Reid Welch]

I am a Mechanical Engineer Reid. I know a reasonable amount about gears.

Then prove it, mate, with words and or piccies? You can get almost any data in a trice from the WWW.

Anyway, I wuv you (becuase I have never pissed off an Australian before; I thought they were all bomb proof?
Look at what they did for the Allied Forces during the last world war?
Without Oz, we'd all be goose-stepping with Dorothy, ja!


)the pain pills are working. can you tell? off for a nappie; see your discussion rebuttal in twelve hours or so(

Cheers and fun,
Epicycloidal Reid, who never finished high school, but who did get six Vicodin from the kindly dentist.

[Reid Welch]

Google Book Search is such a help in learning about past and present manufacturing techniques.
The older books are in the public domain, and so, can be quoted or copied.
Here is the very best (then and probably now) SILENT gear material, which I referenced to above.
It's infinitely tougher than "nylon", though today specialized plastics, moldable like nylon, make the machined laminated cloth gear unnecessarily costly, therefore obsolete. But for strength? This old problem was long ago solved. From: http://tinyurl.com/q2n9s8

840. Bakelite Micarta-D Gears and Pinions. - T. D. Lynch and R. E. Talley. (Elect. J. 13. pp. 368-371, Aug., 1916.)—Noise represents in itself a loss of power, but the chief reason for giving it serious consideration is that it is necessarily associated with vibration. Direct loss of energy due to vibration is of particular importance at high speeds. By eliminating noise, the wear and tear on machinery is reduced and the efficiency of workers is increased. A suitable non-metallic gear material must have sufficient strength to keep the face width reasonably narrow ; it must be hard enough, to wear well, and must not shrink or swell. Metallic reinforcement should be unnecessary, so that two muting gears can be made of equal width to obtain uniform wear. A product of heavy duck bonded with bakelite by heating under very high pressure goes by the trade name of Bakelite Micarta-D. This material is as strong as cast iron ; it is proof against oil, atmosphere, and vermin, and, unless conditions arc unusually severe,, it can be used without bush or flange. The teeth need never be shrouded, and the width of the gear is determined only by the power to be transmitted. The physical properties of this material are:— Tensile strength, parallel to laminations, 10,000 Ibs. per sq. in.; compression strength perpendicular/parallel to laminations, 35,000/17,000 Ibs. per sq. in. ; transverse strength, max. fibre stress perpendicular or parallel to laminations, 17,000 Ibs. per sq. in. ; coefficient of expansion (per in. per 1 deg. C., 0-00002 in. parallel to, and 0-000085 in. perpendicular to laminations ; sp. gr., 1-4; weight per cub. in., 005 Ib.; shrinkage practically zero" up to 100° C. ; oil absorption practically zero ; water absorption (50 hrs. immersion at 21° C.), 0-25 to 2 % by weight, depending on relative amount of edge exposed. The same tools may be used as for steel when cutting teeth, but the cutting speed may be increased 25 % and the feed 50 % ; turning may be done at 400 to 500 ft. per min. with a tool of 30° cutting angle and 10° clearance. Metal end- plates should be used on heavy Micarta-D gears, and always when the pitch diam. exceeds 4 times the face width. The thickness of the end-plates is governed by the torque at the hub. With light torque the chief function of the end-plates is to act as washers, and J in. to J in. thickness is sufficient. With heavy torque the end-plates must strengthen the keyway, and should be J in. to | in. thick, or even be in the form of flanged bushings. Notes on design and applications of these gears are given in the original. Spur, bevel, spiral, and helical gears can be made from Micarta-D. In order that they may mesh properly with metal gears, both must be cut true, lined up accurately, and properly spaced between centres. The back-lash allowance should be double that usual for steel. Free lubrication with oil or grease is necessary. Generally Micarta-D gears can be substituted for steel (untreated), cast-iron, or bronze gears, and with the same dimensions as the metal gears which they are to replace ; they will outlast raw hide and other non-metallic gear materials, and, in some services, will outlast cast iron.

I hope this was of general interest.
The old tech stuff was generally extremely well thought out by men of long and trained experience:
it was the golden era of the Mechanical Age.

______________________

Two corrections at least, are in order:

THANK YOU, Mark, for making me think, even under sedation.

Secondly, the timing gear referenced is not in this thread. I must fetch a link, or just re-describe the gear:
It was a beautiful thing, Westinghouse branded, molded and patent-dated in the face of the gear
and the phenolic-bonded laminations, all hand-laid, many, many layers of cloth, all saturated with thermosetting phenolic resin.
It was a glossy, brown, wonder of workmanship, as was the die it was pressure-cast in, and then the machining of the teeth, beautifully done.
It was a premium product for the demanding Fordist, the man tired of the whine and clatter of the stock, cast iron, half-speed gear.

These things had to be incredibly strong and fatigue resistant, to resist the un-damped, extremely nasty,
hammer-like harmonic vibrations of the slender four-throw Ford crank. Other makers, including Mercedes Benz, used such silent gears in the 20s and 30s, if in lieu of "silent" timing gear chains, which, long term, proved a better method overall.

[Reid Welch]

I learn as I think. I am no engineer but I tremendously respect engineers and others here, like fechter and Bob Mc Cree (I name them only because they are virtual charter members.

=======

About planetary gearing: I was in error. There is nothing inefficient in a well-made three gear reduction box.

The plastic gears can all deform a bit and so, each tooth can shoulder its share of the load.
Efficiency should range (reading old books now) above 95%.

The accuracy of the pinion placement (same for all three gears relative to the sun gear) and smoothness of the mating parts, and bearings: all the details of fine machine work; count for more than perhaps any other aspect of a geared hub motor.

That, plus gears which are heat resistant and tough and fatigue resistant.

----
my intuitively derived opinions... I'm full of them,

Reid

[GTA1]

There is no doubt that technically, very light, strong, and high quality gear sets can be made of a variety of materials --- not just Nylon molded gears.

There are ways to reinforce plastic or resin, use composites or ceramics combine it with metal facings, etc. to get high tech gears that are almost better than metal in every way.

The real question is what is the art of the possible coming out of Chinese manufacturers.

Most of the Chinese Manufacturers are decades away from the point where they have the ability, scale, and scope to be able to market, service, and support products that are well made, well, supported, and provided with reasonable spares and maintenance over a reasonable time: i.e. 7 years.

The best of the Chinese vehicle manufactuers (car and motorcycle) are capable of that now inside China and in a few select markets.

However, China also have hundreds, perhaps tens of thousands, of other small shops, businesses, etc. who can't do that.

What they CAN do is to put together a product that looks good on the surface, works for a while, and sell it for what appear to be a cut rate price.

The dominance of these cut rate firms, in turn, undercut the "name brands" who do provide good engineering, customer service, etc. from charging too high a premium.

Thousands of people who are willing to import the untried products into the major US and other markets from cut rate firms and new entrants, in turn, frustrate the efforts of name brands in building a "name", and getting enough of a premium to support after sales and support, and R&D into products that really work.

What it means for us (the buyers) is the market is filled with mediocre products that by and large don't stand the test of time, and do not gain the benefits of having manufacturers and distributors that are in the game for the long haul.

The exceptions are brands based in the US etc. like Bionx that source their own components, insist on strict quality controls, and of course, charge sky high prices.

Anyone got any ideas as to how to move this forward?

[grandmasterE]

Does anyone have any experience with the BMC 1000W hubmotor yet? If so, give up the details (speeds, acceleration, batteries, and controller)

E.

[Muad'dib]

Does anyone have any experience with the BMC 1000W hubmotor yet? If so, give up the details (speeds, acceleration, betteries, and controler)

E.

I'm building one right now, hope to have it up and running by the weekend. It'll be running at 48v and 50amp. The seller (electric-bikes.com) recommended a 40+amp controller, apparently it needs a lot of power. Waiting on Headway cells, in the meantime I have 5ah of Lipo to get started with. I expect to be able to go 40+mph, but we'll see what the real life speeds are.

[64ragtop]

I was waiting for that myself, Muad'dib, hope it goes well. Sounds like it could be a really happy weekend

ATB

BC

[DahonElectric]

The exceptions are brands based in the US etc. like Bionx that source their own components, insist on strict quality controls, and of course, charge sky high prices.

Anyone got any ideas as to how to move this forward?

During the dawn of the microcomputer age, we had a choice. Build our own computer kit or buy from pre-made and somewhat expensive computers. Remember the IBM XT or AT?!? Or the Apple IIe compared to the clones of questionable quality. Today, we still pay premium prices for Apple computers and PC clones, but they are of good quality and prices to justify the means for lower prices.
Why? I think it is because the acceptance of the personal computer in the internet age drove down prices and offer quality products to entice people to continue buying not just one computer, but many.

Electric bikes need this acceptance as an alternate means of transport. Currently, North Americans view bicycles as recreational vehicles so roads are for cars and bikes be damned. So there's a perception among us that we must match the speed of our bikes at least with some cars. The speed of ebikes can reach up to 60km/h or higher, but this is no longer a bicycle. There is also a perception that riding an ebike somehow degrade our ability to become fit, which is not true. What's true is that, you never get to the level of Lance Armstrong if you ride a bike with assist, but heh it's better than driving a car most of the time where you get no exercise. In order to move forward, we must convince the masses that riding an ebike is cool and an ebike is an alternative to your second car. Bionx bikes, while highly priced, are actually not at all expensive at all and is a good direction they take. No ebikes have a strain gauge and a computer console like all Bionx bikes do. If you need those, you need to buy a PowerTap hub (about $1000+) and a Cycle Analyst ($150) and make the CA work the same as the Bionx control panel. The Bionx bike was like the old microcomputer age where a mouse and a graphical interface was considered lame. DOS and command line was considered the true interface like what we do with our hobby ebikes. Today, a normal Joe and Jane would only deal with a computer using a mouse and Windows or Mac OSX. To move forward, makers must design a electric bike system that rids of all the technical aspect of the bike electrical designs and efficiency and offer solutions that the rider needs. I mean, it's all fine and dandy to talk about the engineering aspect of which drive system is more efficient. I tended to talk that way to my clients before -- I too work in the electrical engineering field. Problem is, this is information overload to them. They are not interested in listening to gears, amps and volts -- in fact they are a major turnoff. They are only interested in one thing and that is, what can an ebike do for me. Today, an ebike does nothing more than an expensive bike with assist that can make you go faster. And yet, you can't take an ebike to compete in an Ironman event either, so making no sense to own an ebike for the masses. And this is true today.

An ebike is only useful to people who have to commute long distances with varying and challenging terrain. For short range travel of less than 10km, a normal bike will work fine. An ebike is useful for people who don't want to commute in congested cities like in Holland, where a bike (albeit slower than a car) can get to places faster than a car could. An ebike makes sense for people hauling stuff.
And yet, I have not seen ebike makers offer solutions like this. All they have done is offer low cost kits with powerful motors at cheap prices. How could a normal Joe and Jane know what to do with it?

[WonderProfessor]

All they have done is offer low cost kits with powerful motors at cheap prices. How could a normal Joe and Jane know what to do with it?

By visiting http://www.endless-sphere.com ...

[Reid Welch]

It has been about one month. It's a lot to wade through on page seven, and most of the verbiage is MY FAULT.

To repeat to make sure there is no error of any reader taking my assertions as truth.
I was wrong. Planetary spur gearing is perfectly efficient as any other sort of spur gearing.

But it DOES tend to make noise. So "we" gear makers, that is, have long used silent materials for gears, even rawhide was used in the nineteenth century for special applications; leather steeped in gutta percha or shellac to make it stronger yet.

For a gear maker to employ NYLON, if that's what they use in Bafangs and eZee motors, etc, is absolute ignorance on parade, or OK for 12mph motors that won't be seeing any tough service, no road shocks, etc.
Nylon: cheap, quiet, soft, thermoplastic that loses even more strength as heated, it then melts at some point.

There are, another poster noted, a variety of moldable (cheap to make) gear plastics that are tough and forever. Whatever Honda uses in their one-lunger four strokes for the half time gear, is silent plastic, tough, heat proof and durable in this super-severe service. Wham, wham, wham, as the ICE engine explosions shock the gears with every ignition.

There is no sense in using steel planets in motors of any sort.
Soft steel against soft steel (the ring) make a very poor wearing combination.
Hard steel against hard steel run in oil, like a proper auto transmission, preferably helical cut, is fine. But not soft steel running in grease, not for a long term of say, ten thousand miles. It won't/can/t wear well. And it may tend to be noisy as heck. Or quiet. Depends on the luck of the machinist. But metal against metal spur gears running at high speeds almost always are NOISE.

Nylon is the worst plastic, practically, for this sort of ebike motor service.
It is not strong enough for long use, especially under shock loads and high temperture.

But I was wrong wrong wrong in asserting that planetary transmissions are lossy.
I was thinking, in error, of the Model T transmission. It is very lossy in "low gear",
but for different reasons than obtain in a fixed-ratio geared motor.

Eh, I'm a blowhard, but most of what I say has mostly truth to it.

Sorry for aggravating or misleading anyone reading this far. I apologize!

r.

[Stevil_Knevil]

Reid, buddy ..you graduated directly from a currie/SLA rig --to a gear-reduced eZee hub motor kit with Ping LiFePO4 battery

New rig is WAAAY more efficient, ya? Guess what -your rig is one of the most efficient eBikes in the terrestrial (or aquatic) world.

An aside: where did the term, 'Rig' come from?
I know that the term, 'Gerry Rigged' (originated during WW2) is considered offensive by Germans

[Stevil_Knevil]

..think back to your blue DrainBrain days

[64ragtop]

.....Planetary spur gearing is perfectly efficient as any other sort of spur gearing.

....But it DOES tend to make noise. So "we" gear makers, that is, have long used silent materials for gears....

....Nylon: cheap, quiet, soft, thermoplastic that loses even more strength as heated, it then melts at some point.

....There are,.... a variety of moldable (cheap to make) gear plastics that are tough and forever. Whatever Honda uses in their one-lunger four strokes for the half time gear, is silent plastic, tough, heat proof and durable in this super-severe service. Wham, wham, wham, as the ICE engine explosions shock the gears with every ignition.

....There is no sense in using steel planets in motors of any sort.
Soft steel against soft steel (the ring) make a very poor wearing combination.
Hard steel against hard steel run in oil, like a proper auto transmission, preferably helical cut, is fine. But not soft steel running in grease, not for a long term of say, ten thousand miles. It won't/can/t wear well. And it may tend to be noisy as heck. Or quiet. Depends on the luck of the machinist. But metal against metal spur gears running at high speeds almost always are NOISE.

....Nylon is the worst plastic, practically, for this sort of ebike motor service.
It is not strong enough for long use, especially under shock loads and high temperature.

r.

Reid, thanks for the rundown. I've thought for years why such cheap, soft, high temperature intolerant plastics are used is because They're CHEAP!
No other reason has been presented, so there ya have it! It seems that you've overlooked a possible combination, brass or bronze gears in the chain, but moldable gears will inevitably be cheaper than machined ones - and cost will always be a consideration.

What's happened to Knuckles? I thought he was pretty well engaged in finding better gear material for the Bafangs, but I haven't seen much from him lately. I PMed him about another matter and got no response.

Well, no doubt, better stuff will be forthcoming. But it'll take demand pushing the makers to use slightly better materials and not charge much more than they already do. Even a super plastic, like the stuff Honda uses, shouldn't raise the finished product price by more than ten percent or so.

ATB

BC

[Papa]

I've thought for years why such cheap, soft, high temperature intolerant plastics are used is because They're CHEAP!
No other reason has been presented, so there ya have it!

Why use "cheap" non-metal gears?....

1. Less noise
2. Lower manufacturing costs and lower replacement costs.
3. The more expensive metal sun and ring gears last indefinitely.
4. Lower weight.
5. Usually survive longer with minimal lubrication.

But most importantly...

6. The smaller, non-metal planetary gears act as fuses do in an electrical circuit - they protect the more expensive, and often, non-replaceable parts - often including electrical items such as stator windings. And when a plastic gear gets shredded, the loose fragments cause little or no damage to other, more expensive parts.

[shady8282]

I'm building a folder. Is there a geared hub motor out there that will go at a decent speed on a 20" wheel at 36v? Maybe I should just ask what is the fastest geared hub motor for a decent price? Advising me to increase to 48v, 60v or 72v is not necessary, I know what that would do. I'm looking to use materials I have on hand and just add the motor without having to double up batteries or buy new ones. So what's the fastest? Sorry to limit my question, but people on endless sphere go off in so many different directions that the original question often gets lost. Thanks.

[redorblack]

I'm building a folder. Is there a geared hub motor out there that will go at a decent speed on a 20" wheel at 36v? Maybe I should just ask what is the fastest geared hub motor for a decent price? Advising me to increase to 48v, 60v or 72v is not necessary, I know what that would do. I'm looking to use materials I have on hand and just add the motor without having to double up batteries or buy new ones. So what's the fastest? Sorry to limit my question, but people on endless sphere go off in so many different directions that the original question often gets lost. Thanks.

I'd have to pull out the fourth battery and recalibrate the controller to verify, but my kit from PedalGreen at 36v was doing about 21mph. I added a fourth battery to it for the speed increase to 25mph. That's on a flat no wind, no pedaling. Gets about 8-10 miles of varied terrain mostly wide open throttle. Randy sells the kits without batteries, just looked and it's $319 for everything you need minus batteries. I believe from what other members here say, that it's a Bafang motor. It's a nice little controller with 63v caps and fets, so if you do want more speed, just add a battery... or two

[mwkeefer]

Shady,

There is a thread here on ES with the specs on the Bafangs (ie the motor codes)... the fastest they seem to have available would spin around 380rpm on 48v. I am fairly sure that the bafangs available from BMSBattery can be ordered in the "fastest" model bafang has available (will be able to confirm this shortly, one is on order... should be the highest RPM per volt motor bafang has - according to BMSBattery it is for 16-20" designed for 20mph at 36v (design parameter was LiFePo4 so 36v is really 43 hot to 41 within moments of discharge). I am afraid that at this point, in the low end, cheap market that is the best I can "confirm".

Don't forget in addition to over volting you could also do Delta/Wye. I am fairly sure these brushless geared hubs are mostly wye from the factory so get a slower RPM model and rewire for delta... that will increase the top end speed by 1.73 and I have seen other threads here with some details and pics of the conversion. So how fast do you want to go? 35mph on flats? if you needed that speed, go with the fastest model and re-wire it delta - should get you to 34-35mph but prb will kill gears (others are welcome to correct me - please).

Everything I've read about the bafangs (and most of the other geared hubs) indicates they work great within their designed "limits" but when you push them harder (like you would a direct drive hub) you end up with mush for gears... I assume you have read all this already also.

I think there are some of the higher end geared hubs that could perform a bit better and be more efficient but they cost quite a bit more... is an RC build totally out of the question? You could do a 2-3x legal US power RC build for about 450 + batteries (rough estimate) but it would be light, powerful, could be manually geared (a bit more complex but shiftable) for better efficiency.

We are in the same situation - 20" folder and no good, light weight, performance geared brushless hubs for the size to get a decent speed... Im fearful that anything wound fast enough will be very low torque in these 250-350w variety.

-Mike

[mwkeefer]

Wait GreenPedal? You don't mean Green Wheel, ie this one:

http://www.msnbc.msn.com/id/29259226/

more information - detailed technical background

http://optics.csufresno.edu/wiki/ECE1S0 ... _Hub_Motor

-Mike

[NewbE-biker]

Hi All, ok I'm learning about all the hub motor stuff to work on my own e-bike project and the pictures on this thread are so helpful. I found some youtube vids of what looks like the insides of these motors, and of course seeing the motion of the gears makes it way more clear how all those this-way-that-way gear ratios work. Two good vids:

-

-

Does anybody know if these are the "Bafang" motors? Thanks!

Here's the page of the motor in that video, if anyone recognizes it. I'm trying to figure out which retailers use which motors:

http://cleanrepublic.com/hill_topper_electric_bike_conversion_kit.html

?

[The Mighty Volt]

I was thnking of spending some money on but I wanted to wait and see what you guys thought of it first.

http://cgi.ebay.ie/ws/eBayISAPI.dll?Vie ... Track=true

BMC Geared Brushless Rear Hub.

36v 25A rated controller. I have a 48v 20Ah battery....how would that mate-up to this kit??

400W rated....hmm.....I was looking for something that had a bit more animal..would this 400W hub have some torque, real hill climbing stuff??

And the price?....US $649.95, steep, or fair? {plus another $100 to ship it to me but thats OK and more than competes with inferior chinese posting options}

Anyways, if I bang this sucker on my bike, and mate it to a 48v 20Ah mother, how am I going to feel?
Here is a pic, I am sure the seller will not mind, as I am basically advertising it for him.....