Brushless Geared hubmotors: BIG list & details

[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/ECE1S09:3-in-1_Wireless_Electric_Bicycle_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:

-[youtube]YjMZ_-RmZcE[/youtube]

-[youtube]ng1FRF_T4ck[/youtube]

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?ViewItem&item=290382398527&fromMakeTrack=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.....

 

[1-track-mind]

MV
Cycle9.com has that kit (BMC v-1) on sale for $579.00 with free shipping.

 

[kriskros]

bafangs have been run at 72volt 20 amp.... try holmes hobbies.... laced motor $300...he also has puma motors

 

[The Mighty Volt]

bafangs have been run at 72volt 20 amp.... try holmes hobbies.... laced motor $300...he also has puma motors

It does not seem clear if he does it with or without all the trimmings....better mail him I guess!

 

[spinningmagnets]

A few months ago, ampedbikes.com began selling a geared hub for front or rear. 20-mph at 36V. $450 complete (wheel/controller/throttle, etc) with NO battery or charger. I "think" you can get the rear hub with a 6-gear cluster...

http://www.ampedbikes.com/kits.html

 

[Whiplash]

Hey guys, I see a lot of talk about the plastic gears, and I thought, why not take a page out of the 700R4 automatic transmission beef up book and replace the three sun gears with 4 or 5 smaller ones? The teeth seem to be the weak link and the way these planetary gear systems work, is the more planets you have the more the load is distributed over all the gears thus limiting the force applied to each tooth and making the assembly MUCH stronger! The transmission I am talking about, with added planet gears in the drive can be made more than 100% stronger by doing this, it would seem quite easy to do in this instance! I can't believe nobody has tried this?? JUST AN IDEA!! One of these babys with some good volts/amps would seem like a GREAT alternative for the slower off road mountain biking I like to do!

-Whip

 

[Mark_A_W]

Hey guys, I see a lot of talk about the plastic gears, and I thought, why not take a page out of the 700R4 automatic transmission beef up book and replace the three sun gears with 4 or 5 smaller ones? The teeth seem to be the weak link and the way these planetary gear systems work, is the more planets you have the more the load is distributed over all the gears thus limiting the force applied to each tooth and making the assembly MUCH stronger! The transmission I am talking about, with added planet gears in the drive can be made more than 100% stronger by doing this, it would seem quite easy to do in this instance! I can't believe nobody has tried this?? JUST AN IDEA!! One of these babys with some good volts/amps would seem like a GREAT alternative for the slower off road mountain biking I like to do!

-Whip

I already looked into that for my MAC motor.

It has 3 planets. But even 4 won't fit.

You need to design the motor from scratch for 5 or 6 planets.


However, the composite BMC gears are holding up fine. (As are everyone else's MAC plastic gears.)

 

[amberwolf]

Would it basically require smaller teeth on sun/planets/annular, so that more smaller planets could be used for the same ratio? And a larger diameter sun? Or does it just need the larger sun and smaller planets?

 

[Mark_A_W]

Well, you have to keep the ratios the same (or mostly the same).

Smaller teeth are weaker..could be 6 one, half dozen the other.

I'd have to partially design and analyse it. Seeings as I can't make it (cheaply), I aint doing that.

 

[Whiplash]

You would use a smaller diameter with the same tooth size but lesser count and then use more of them, the ratio would not change as that it dictated by the diameter of the outer ring gear and the inner housing diameter I believe...