Hub Motor queries

[Lurkin]

I am planning my next bike now. The prior was a hardtail, 250w Bafang mid drive.

Requirements are:-
- higher reliability
- more power. thinking probably 1000- 1500w should be sufficient.
- low complexity motor
- inconspicuous to avoid unwanted attention (rules out mid drives like GNG etc)

So that leaves hub motors, drive drive or geared. I was originally planning a high power bike with a flux frame and 3000w mxus motor. Whilst this would have the ease of use with a decent battery compartment, it's just for commuting on bike trails with a max speed of ~45km/h and a crusing speed of around 35km/h - seems like is overkill/ over expenditure. Accordingly, I considering switching back to a bike retrofit.

I've had a bit of search on the net re hub motors but not too sure where to start. Really, I need a hub motor which is smaller and can pass off as a large hub or dynamo hub rather than a larger motor. i.e. the brake disc and cassette should help conceal it.

At this stage I think I would prefer direct drive because I really, really appreciate the simplicity of the design. However, others have noted geared hubs would extend range (will need to do 80km per day on this).... I really don't want to have to deal with fiddly plastic gears again.

What can you suggest for me?

 

[Nobuo]

I don't think it would be possible to have a small DD hub, smallest direct drives are about 245mm diameter and weight ~6Kg. Smaller ones need gears to reaching reliable rpm.

If you don't have the stealth look as a main, I would put together this components in order to make a powerful build that fits your speeds requirements.

48V 1000W continuos ~1500W peak front or rear hub build, for around $286

- Motor: Conhismotor 1000W DD hub 6.5Kg (~1500W peaks and indeed capable of more) ($142 if you buy two units)
http://www.aliexpress.com/item/High-Quality-Cheap-ebike-wheel-front-motor-48V-1000W-Ebike-Front-Hub-Motor-Brushless-Gearless-Hub/32226913046.html

- Controller: 15 fets 48V 1000W
http://www.aliexpress.com/item/High-Quality-GREENTIME-15-Mosfets-48-84V-1500W-Dual-mode-Sensor-Sensorless-Brushless-DC-Motor-Controller/32218294528.html?http_swift_null=

- thumb throttle, brake cut and regen acivator aluminium levers, 3 speed switch:
http://www.aliexpress.com/item/Electric-Bicycle-Thumb-Throttle-without-Handle-Bars-no-battery-indicator-no-on-off-switch-Wuxing-Brand/583516197.html
http://www.aliexpress.com/item/Free-Shipping-All-Aluminum-Alloy-Brake-Lever-for-Electric-Bike-Ebike-Brake-Lever-Electric-Scooter-Brake/1998595017.html
http://www.aliexpress.com/item/Free-Shipping-Chinese-Electric-Bicycle-3-Speed-Control-Switch-Ebike-Three-Speed-Switch-3-wires/753911955.html

- spokes (40 units):
http://www.aliexpress.com/item/E-bike-bicycle13G-Black-Anodized-spokes-and-copper-nipples/1886690978.html

Only the motor have added duty customs extra costs

 

[Lurkin]

How often do geared motors actually fail/ require parts or servicing? (I'm referring to ones used in their expected wattage, not overvolted etc)

 

[Nobuo]

As long as I know it depends of quality, I've heard 3 years, 6 months, never.. but late or soon gears teeth finally broke for impacts, too much power, too much weight..

One of the most strongest geared hubs known are Mxus XF07

http://www.aliexpress.com/item/36V-...-Motor-Front-Wheel-Drive-MXUS/1880894600.html

http://www.aliexpress.com/item/XF-X...r-electric-cars-matte-silver/32375526066.html

 

[Drunkskunk]

Geared hub drives are actually less efficient than a direct drive at cruising speed. they only extend your range if you do a whole lot of stopping and starting. But geared drives are much easier to hide.

The strongest geared drive by far is the MAC 500w Available from here. All gears can fail, but the MAC is one of the very few geared motors strong enough for off road use. Failure is very unlikely when used within recommended limits (1500 watts peak) Its smaller than a Direct drive motor, and would more or less hide behind a 203mm disk and sprocket set.

A direct drive motor would be 5-10% more efficient at cruising speed and nearly dead silent running, but nothing on the market could be hidden. it's going to be obvious you have something huge in your wheel. The Old Crystalyte 408 series motors were smaller and even quieter, but they aren't sold anymore. If you happened to find one used, it would be something to consider.

 

[Nobuo]

I'm agree with all, very informative.

I would add only that another little difference is that geared ones has less drag than DD, because their freewheel/clutches built-in are maybe more indicated if the bike is going to be used several times full pedalling.

However, by my experience, I would choose mainly DD hubs because the regenerative brake that is really strong, useful and can extend the range between 5% - 10%

 

[markz]

1500W leaf dd - Direct Drive aka DD are silent
MAC geared, geared motors fail when they over-heat, by stalling it when you throttle up. Geared are noisey.
LeafMotor.com
Yescomusa.com
em3ev.com
ebikes.ca
Greentime on Aliexpress (Motors, Controllers, Throttles, no batteries)

 

[dogman dan]

Gotta love a guy who wants to be inconspicuous, but run 1500w. I suppose compared to a typical 3000w setup, it will be a lot less conspicuous.

IMO, what gets conspicuous is speed, not power or size of motor. This is one reason I really like the slow wind direct drive motors. You can run 1000-1500w, (48v and 20-25 amps) have great power for hills, have great efficiency in stop and go, and since it's only going to go 20 mph or so, great cruise efficiency too.

But you can't sell this Endless Sphere crowd on it. :lol:

Not knocking the geared motors though, They are light, smaller than dd motors, not that loud, not that fragile, and have more top speed. Chances are, A Mac or similar larger geared motor run on 1000w will please you. I sure like mine. The only caveat is don't jump them, and if you do huck a small pop like riding off a curb, get off the throttle to land. If you do break one that way, the fix is really easy.

 

[Nobuo]

IMO, what gets conspicuous is speed, not power or size of motor. This is one reason I really like the slow wind direct drive motors. You can run 1000-1500w, (48v and 20-25 amps) have great power for hills, have great efficiency in stop and go, and since it's only going to go 20 mph or so, great cruise efficiency too.

Thanks for the input!

I have a simple question:

If I have both similar motors pulled at the same voltage, one a high kv motor and another a medium kv motor, I know that for a cruise stable speed, for example 20mph on both, the efficiency is the same if I'm not wrong.

If I get the medium kv motor and pull it with the voltage enough to reach the same speed that the high kv motor, both at full throttle, which one is more efficient?

the medium/low kv motor at higher voltage, or the high kv motor at lower voltage?

 

[Lurkin]

I really like the slow wind direct drive motors. You can run 1000-1500w, (48v and 20-25 amps)

Welcome to suggest an alternative to those already noted in this thread. 1500w is not a "must have". I just don't want to buy another underpowered tinker toy which will drop it's guts every 3,500 km.

Bearing mind 80km per day x 5 days a week = 400km per week.
3,500km/400km = ~9 weeks.

So I'm expecting problems every nine weeks from the current set up.. which is the main reason for going for a (hopefully) more durable, higher power set up.

The speed will be about the same. 20mph = ~32km/h which is roughly what I will be travelling at. I don't want rocket speed, it's not conducive to avoiding accidents whilst zombieing in the morning to work. The additional torque will probably also come in handy.

Is a 9kg frame too heavy for this? Do you think a flux frame is too conspicuous?

I suspect the Mac motor is going to be the pick.

 

[oobagooba]

Stealth and reliable around 1200w, a few geared hub motors are beefed up by vendors/manufacturers. Being in Aus best is probably Mac from Paul, could get your battery & controller from him now or upgrade later, 12fet, 25r, etc. Also have choice of hub windings speed vs. torque.

This guy in california http://gocarlite.com/product/high-end-geared-motor-kit/ has cheap US shipping w/ beefed up Mxus geared. It is a good kit but only 25a. I have one, does around 40kph on flats with good hill power.

Grin canada may have a hi-end gear motor but they cost more. what is a flux frame?

 

[Lurkin]

Stealth are selling a stealth fighter frame variant under the name Flux. Upside - easy to house battery, downsides being weight and that it doesn't have the rear triangle of an ordinary bike, thus looks odd.

I think I will go down the bike retro fit rather than flux. It's too odd looking to pass as a ordinary bike.

I just can't bring myself to butcher a brand new bike in order to change it into a ebike. I was considering buying a Giant Stance and going from there.

I take it I will need torque arms. Is the best method the DoctorBass screw/glue on, or is a bolt on enough? It would be better if I didn't have to modify it in a way that is not reversable, but I take it the axle thickness is much greater than an ordinary bike?

 

[dogman dan]

Oh yeah, another way to be inconspicuous, a Stealth frame, or any other "battery box with wheels" frame.

Re the slow motors, once spun up to a reasonable speed, any differences in efficiency will be pretty damn small and hard to measure. Exact same motor, but different windings and voltages I mean. Then you also get some big differences that can happen depending on the volts and amps you use, or the wheel size, combined with your weight, and how you ride.

Bottom line, if you keep you wheel pretty small, and the power pretty high, the performance improves so much you don't lose anything much anymore when you leave a stop sign. If you want the best efficiency from any hub motor, 20" wheel for the win.

The problem with dd motors is when the wheel is 26" or larger, and the power is kept legal, at say 700-1000w depending on where you live's laws. A 48v 1000w kit that is truly 1000w max will have a controller only about 20-22 watts. In this specific situation, if you limit your speed to about 20 mph ( so no difference in wh/mi from going faster) on a fast motor, you will lose a lot of energy if you are riding in the city, stopping every half mile, or at least slowing a lot for intersections. The motor just goes bleah for the first 50 feet from each stop. Till you get to 15 mph it's wasting power. But a slower rpm motor will get out of that stalling condition at a lower speed. So it stops wasting power in only 25 feet. In this specific case, the slow motor will have longer range for sure. This is why I love them on my grocery getter.

The result is about 20% better efficiency in city riding from a slow motor, vs a faster one. This is not guessed, I saw it time and time again, riding 9 continent type motors in 9x7 winding, and slower 6x10.

Of course, if you want faster from the 6x10, then you have to run 72v, and ideally a lot more amps too. At that point things get very perky, and performance starts to approximate that of a 9x7 in 20" wheel. But the downside is now you have to carry and charge a 72v battery. So in a lot of ways, for a DD motor, the 20"wheel rules. A geared motor like a Mac has the gear reduction, and will get very good stop and go efficiency too.

On the other hand, at a steady cruise, comparing say, 25 mph, 26" wheel, and the motors are 9x7, 6x10, and a Motor similar to a Mac, and a 5304 there will only be very small differences in the wattage seen on the screen, when cruising 25 mph on all the motors, regardless of motor, voltage, or controller amps.

This makes sense, if the bikes are similar in drag, 25 mph cruise will take about 800 w for all of them.

 

[Lurkin]

I wanted a Flux alpha, but couldn't justify it looking like a bike. Fail.
Tried to buy a second hand frame through gumtree, but upon checking the frame number with the police, was warned against buying it.
Can't bring myself to butcher new bike.
Full circle - Flux Beta is the answer.

I think the discussion in the thread has been too focused about speed/1500w. The 1500w is an estimate, not a requirement. I've really only ridden 250w or 3kw+. In between is a bit of a mystery as to what will suffice or not. I'm at the stage where I probably need to go and ride a 500w, 1000w and 1500w bikes with similar weight to work out which is ideal. The problem is I don't know anyone who has those and I don't really have time to work it out.

It's entirely possible 1500w is well more than I need, I really want to pick the minimum motor requirement to get it done rather than have to lug more batteries/weight for more (unnecessary) acceleration/speed. I will probably travel at 30 - 35km/h, going up to 40km/h very occasionally. I really just picked 1500w because next step of direct drives seemed to be around that and I'm hoping they are made to a stronger construction than the 250w stuff I have had previously.

I really like the simplicity of a direct drive, not to mention to the silence of them. Geared just seems like asking for problems and noise, neither of which I want. Of the 40km (each way) trip, it's about 50/50 as to the types of riding described above. The first half involves going on the road, past the city, then onto bike trails for the other half. The second half literally has about three traffic lights to stop for.

I've pretty much narrowed down the list to:-
Nine continent motor (9c) (Controller isn't ready to be used with CA)
9C clone (BMS Battery) (failed to reply to any communication requests)
Leaf motor 1500w motor
Mxus 3000w (too much power)
Clyte TC3080? (too expensive)

I have already enquired with Paul to see if he is still selling 9C clones or similar, but he has advised there was too many problems with hall sensor failures.

BMS Battery have ignore information requests. Given they cannot be bothered responding to me at all, I cannot be bother dealing with them either.

Went to E-MTB to pick up a nine continent kit, but was advised on arrival they had run out of cycle analysts...

Not too sure what to do next. I am hoping to also use a cycle analyst with data analogger to track my rides (unnecessary, but would be sweet) so it would be ideal to have a controller which works well with Grin products (which the nine continent controller wouldn't). I have looked at buying from Grin, but between the CA/AUD relationship and shipping it gets pretty pricey.

It would be nice to buy from someone local, who has competitive pricing, controllers conducive to using a CA and can actually deliver on what they say they have... any suggestions?

 

[markz]

You want the highest Kv motor, more copper is better.

 

[Lurkin]

So of 5 * 13T or 4 * 16T I should take 5 * 13T? (48v 1500w dd leaf motor)

Hopefully it's 5 * 13t because that's what I've ordered!

 

[markz]

4 would have been higher kv.

 

[Lurkin]

5 is the slower wind though... which is what I'm after.

 

[markz]

OK, you factored in your controller and battery then for optimal speed goal. Good Stuff!

 

[Lurkin]

I take it your being sarcastic. Given I haven't bought a controller or built a battery yet, I can have any configuration I want?