Hub motor selection guidance: 3kw unbranded vs 5kw QS

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81style   10 mW

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Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 81style » Oct 18 2018 3:36pm

Friends...
I'd like some guidance selecting between the following two hub motors (both offered from em3ev): I'm shooting for a 3kw build, so the 3kw option above seems logical, but it's an unbranded motor which makes me a little uncomfortable since I'm unable to research the product prior to purchase.

The 5kw option is made by QS, a manufacturer known for high quality products. Added benefits are redundant hall sensors and larger stator. Drawback here is the weight, which is 10lbs/4kg heavier than the 3kw motor.

So I want to get a sense from the community if the brand quality and other benefits of the 5kw motor are worth the added weight. (note: I'm not concerned about the difference in cost between the two motors).

Thanks for whatever insight and guidance you can offer.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by spinningmagnets » Oct 18 2018 5:16pm

Once you are committed to a 3-kW build, it will never be light. You will not toss it around onto a bike rack mounted to your car, or pull it up with ropes onto the ceiling of the garage. That being said...I have manipulated a 5-kW hubmotor bike, and the weight was astonishing. I would rather build a 3-kW rear hub, and add a geared hubmotor onto the front to gain some extra power.

You may find that the 3-kW hub is enough by itself (adding ferro fluid), so...I would try that first. Just get a 5-kW battery pack, you wont regret over-speccing the battery.

52V X 100A, or...60V X 85A, or...72V X 70A

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 81style » Oct 19 2018 11:27am

spinningmagnets wrote:
Oct 18 2018 5:16pm
I have manipulated a 5-kW hubmotor bike, and the weight was astonishing.
Do you think a 10 lb reduction in weight would make a significant difference in your experience?

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by neptronix » Oct 19 2018 12:04pm

10lbs more is alot when the bike is already 70lbs.

This is why i'm a fan of the leafmotor 1.5kw on about 4kw of peak power, tuned to do 2kw continuous ( it can handle it, it's underrated ).
I could still pretty easily flip the bike over for a tire change or carry it upstairs with a few grunts along the way :lol:

Some people claim that hubsinks and ferrofluid on such a small motor increase it's continuous capability to 2.5-3kw.

The mxus 3kw ( or one of it's clones ) gets you 2 more lbs and a more likely realistic rating for the 45mm hubs is around 2500w continuous.. add ferrofluid and/or a hubsink and you are up to meeting a 3kw continuous requirement.
( yes, i owned a leafmotor and a MXUS 3kw.. the 3kw was very underwhelming. Later found out that the 3kw rating was done in a 20" wheel, which is a real cheater way to do it. )

Otherwise if you want low weight and high power, RC motors with dual stage reductions to the rear are the only way to go. But those setups are kinda exotic and still in the 'fabricators only need apply' stage at this time.
Efficiency is everything :bolt:

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 81style » Oct 19 2018 1:02pm

neptronix wrote:
Oct 19 2018 12:04pm
10lbs more is alot when the bike is already 70lbs.
I actually anticipate that my final build will weigh in at over 100 lbs since I'm using an EEB frame and looking to incorporate the largest battery that will physically fit (upwards of 20s10p).

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by josephm15234 » Oct 24 2018 4:34pm

I'm basically in the same boat. I'm going to be placing my order soon on em3ev and am leaning more towards the 5kw QS motor. Only thing I'm hesitant on is the fact that you can only use the single speed freewheel on it. I guess its not that big of a deal when its pushing so much power though haha.

Did you make a decision on which motor yet?

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 2WheelsMovesTheSoul » Oct 24 2018 5:27pm

81style wrote:
Oct 19 2018 1:02pm
neptronix wrote:
Oct 19 2018 12:04pm
10lbs more is alot when the bike is already 70lbs.
I actually anticipate that my final build will weigh in at over 100 lbs since I'm using an EEB frame and looking to incorporate the largest battery that will physically fit (upwards of 20s10p).
LOL, my EEB is already 148lbs with a 20s14p pack, 18" moto wheels, tubes and tires. Probably end up closer to 165lbs once I get my 22s19p pack.

If you ain't jumping this bish, get the QS motor, I've pushed over 10k thru mine and with the FF+hubsinks and it hits 60mph with ease.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 81style » Oct 24 2018 6:05pm

Nice to see some activity on this thread. Thought it may have fizzled.
josephm15234 wrote:
Oct 24 2018 4:34pm
Only thing I'm hesitant on is the fact that you can only use the single speed freewheel on it.
Single speed is the only way I go because there's enough stuff crowding my limited handlebar space that I don't need to add a shifter up there too. Also, I find derailleur tuning to be horribly tedious. I can do without. When converting a multi-speed to a single-speed, I use a beefy freewheel spacer.
josephm15234 wrote:
Oct 24 2018 4:34pm
Did you make a decision on which motor yet?
Not yet. I'm going to weight my (incomplete) build to project final build weight and get an idea of how significant a 10lb increase in weight will be.
2WheelsMovesTheSoul wrote:
Oct 24 2018 5:27pm
LOL, my EEB is already 148lbs with a 20s14p pack, 18" moto wheels, tubes and tires. Probably end up closer to 165lbs once I get my 22s19p pack.
Heaviest. Build. Ever. Where do you get battery packs that large?
2WheelsMovesTheSoul wrote:
Oct 24 2018 5:27pm
I've pushed over 10k thru mine and with the FF+hubsinks and it hits 60mph with ease.
Even if I end up with the 5kw QS, I'd probably limit it to 3kw max via CycleAnalyst since that's currently the upper limit of my comfort zone.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 2WheelsMovesTheSoul » Oct 25 2018 10:34am

2WheelsMovesTheSoul wrote:
Oct 24 2018 5:27pm
LOL, my EEB is already 148lbs with a 20s14p pack, 18" moto wheels, tubes and tires. Probably end up closer to 165lbs once I get my 22s19p pack.
Heaviest. Build. Ever. Probably... :lol: It was 148lbs last time I weighed it.
KIMG0393[1].JPG
Since then I've added a moto style seat, 80w LED headlight, turn signals, tail light, moto horn, bar end mirrors, a BT audio system, a second DC/DC converter, USB 2a charge port, a bulk charge port with a 50amp Anderson connector, a needle bearing throttle with 0-5v converter, alarm, GPS tracker, dual 1080 DVR, light sensor for automatic headlights, Mudhugger fender, faux fork gaiters and CRF-50 front and rear fender
KIMG0445[1].JPG
Still a work in progress.

Where do you get battery packs that large? Build them. Pulling a range of 60-120a during my rides.
2WheelsMovesTheSoul wrote:
Oct 24 2018 5:27pm
I've pushed over 10k thru mine and with the FF+hubsinks and it hits 60mph with ease.
Even if I end up with the 5kw QS, I'd probably limit it to 3kw max via CycleAnalyst since that's currently the upper limit of my comfort zone. I thought the same at first, but my single cylinder KTM makes 63hp and weighs in at 255lbs. I'm used to it. Surprisingly, I prefer the EEB since its so quiet and doesn't rattle my teeth.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by Jonno » Oct 25 2018 11:31am

Hi guys,
My EEB about 120lbs with a QS205 on a 19" rim + 5.6kgs of apt AE96600 controller and 100v @20.8ah. single speed as you can't keep up with it past about 17mph. Controlled via a CA V3.
3 position switch eco 100a, offroad 200a and mad 300a+. Weight is realistically not a factor on EEBs as you're never going to make a lightweight bike .

As for EM3EV's 3k motor - I had one a couple of years ago - nice motor . obviously not a patch on a QS205. Sold it to upgrade and it's still going strong.

Jonno
EEB frame, 888 forks, QS205 V3 , APT AE96600 600a controller, 113V @ 21AH Lipos 20c 325a burst, Hope 203mm brakes, CAV3 with GPS : faster than you want to go :lol:

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 2WheelsMovesTheSoul » Oct 25 2018 12:40pm

Jonno wrote:
Oct 25 2018 11:31am
Hi guys,
My EEB about 120lbs with a QS205 on a 19" rim + 5.6kgs of apt AE96600 controller and 100v @20.8ah. Weight is realistically not a factor on EEBs as you're never going to make a lightweight bike.
Ahh, yes. Someone is speaking my language.

I don't think anyone bought and built up an EEB frame to save weight. The appeal for me was the oversized battery compartment with a rigid, sturdy frame plus the built in torque plates on the swingarm.

Even at 150lbs, the bike feels nimble and very easy to ride. Several of my supermoto buddies have ridden it and compare it to the size, feel and performance of an XR100.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by harmonist » Oct 25 2018 9:24pm

Yeah there's no way you'll limit it to 3kw with that setup, 3kw sounds powerful but isn't much really, I've got an eeb with the smaller edge 1500w hub and I push that over 6kw every ride for taking off at a good speed in front of traffic at the lights, even then I long for some more watts on occasion, the 12fet controller didn't last long so using 18fets now, top speed around 45-50mph but never need to use it, around 35mph is a good cruise speed for me, one day I'll get a QS too I think if the edge doesn't last :)

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 81style » Oct 26 2018 10:49am

Thanks for the input everybody- really helps frame my thinking.
Jonno wrote:
Oct 25 2018 11:31am
As for EM3EV's 3k motor - I had one a couple of years ago - nice motor . obviously not a patch on a QS205.
2WheelsMovesTheSoul wrote:
Oct 25 2018 12:40pm
I don't think anyone bought and built up an EEB frame to save weight.
2WheelsMovesTheSoul wrote:
Oct 25 2018 12:40pm
Even at 150lbs, the bike feels nimble and very easy to ride.
harmonist wrote:
Oct 25 2018 9:24pm
Yeah there's no way you'll limit it to 3kw with that setup, 3kw sounds powerful but isn't much really
So I guess I'm leaning toward the QS option now. Future proofing is never a bad idea.

Next question would be whether I should use 17" or 19" rims. I'm fully aware of the torque vs speed tradeoffs, but considering the outer diameter of the QS motor and the inner diameter of the rim...
  • Would spoke angles on a 17" rim be too extreme, causing unnecessary tension at the nipple? I'd be using 10 gauge spokes.
  • Would access to the inflation valve be a problem with a 17" rim due to limited clearance?
  • Are inner tubes easier to find for one size or the other?

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 999zip999 » Oct 26 2018 11:03am

I love my powervelocity 18fet bt controller. The QS 205 could use a 24fet. Would be a little scary. But you could tune via your phone
Plus a temperature probe so your motor will last a very long time. You need 6k or more for a real smile. The kind that's can't be wiped off.
Last edited by 999zip999 on Oct 26 2018 11:38am, edited 1 time in total.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 2WheelsMovesTheSoul » Oct 26 2018 11:33am

81style wrote:
Oct 26 2018 10:49am
Thanks for the input everybody- really helps frame my thinking.

So I guess I'm leaning toward the QS option now. Future proofing is never a bad idea. :bigthumb:

Next question would be whether I should use 17" or 19" rims. I'm fully aware of the torque vs speed tradeoffs, but considering the outer diameter of the QS motor and the inner diameter of the rim... Nah, if a QS 273 can fit, this 205 should be fine. viewtopic.php?t=83797
  • Would spoke angles on a 17" rim be too extreme, causing unnecessary tension at the nipple? I'd be using 10 gauge spokes.
Shouldn't be too bad.
  • Would access to the inflation valve be a problem with a 17" rim due to limited clearance?
No, the right air tool should have the correct angle to mate with the valve stem.
  • Are inner tubes easier to find for one size or the other?
Personally this... and availability and selection of tires is ultimately what got me on the 18's. There's also the matter of how wide the swingarm is VS the max width of tire. With a 17" you can run a 3.25" or 3.50" rear tire but with a 19" the widest you can fit is a 3.00". Say you run the 17" with a fat 3.50" rear, that rim + tire + tube combo might weigh 2-3lbs more than a 19" with 2.75 or a 3.00. There's quite a bit more than the torque vs speed tradeoffs to consider.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 81style » Oct 26 2018 12:25pm

2WheelsMovesTheSoul wrote:
Oct 26 2018 11:33am
Nah, if a QS 273 can fit, this 205 should be fine. viewtopic.php?t=83797
The example you reference is on 18" rims and radially laced. Because I'm considering cross-lacing on a 17" rim, this may be an apples and oranges comparison. Thanks tho.
2WheelsMovesTheSoul wrote:
Oct 26 2018 11:33am
  • Are inner tubes easier to find for one size or the other?
Personally this... and availability and selection of tires is ultimately what got me on the 18's.
I'm planning on using Shinko 244 tires. They come in 3x17 and 2.75x19, so I figure that would work fine in either scenario.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 81style » Oct 26 2018 12:31pm

2WheelsMovesTheSoul wrote:
Oct 26 2018 11:33am
There's quite a bit more than the torque vs speed tradeoffs to consider.
Indeed, which is exactly why value the ES community's input on these matters.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 81style » Oct 26 2018 2:28pm

2WheelsMovesTheSoul wrote:
Oct 26 2018 11:33am
With a 17" you can run a 3.25" or 3.50" rear tire but with a 19" the widest you can fit is a 3.00". Say you run the 17" with a fat 3.50" rear, that rim + tire + tube combo might weigh 2-3lbs more than a 19" with 2.75 or a 3.00. There's quite a bit more than the torque vs speed tradeoffs to consider.
Shinko provides a fairly comprehensive tire spec sheet. Time for me to do some caliper measurements on my EEB frame.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 81style » Oct 26 2018 10:29pm

81style wrote:
Oct 26 2018 2:28pm
Time for me to do some caliper measurements on my EEB frame.
Took measurements this evening and turns out that the 17" rims will fit much better than 19" rims in terms of both width and diameter, even with the wider tires. So there we have it: 17" wheel set with QS motor prevails!

Thanks everyone for your wisdom and counsel. Couldn't have broken out of my analysis paralysis without the ES community. :D
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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by amberwolf » Oct 28 2018 1:44am

81style wrote:
Oct 24 2018 6:05pm
2WheelsMovesTheSoul wrote:
Oct 24 2018 5:27pm
LOL, my EEB is already 148lbs with a 20s14p pack, 18" moto wheels, tubes and tires. Probably end up closer to 165lbs once I get my 22s19p pack.
Heaviest. Build. Ever.
Not really. CrazyBike2 was more than that, over 200lbs. The SB Cruiser trike is twice CB2's weight (more now with the new additions).

There's other heavier bicycle-class builds here on ES, and definitely heavier motorcycle-class ones.


FWIW, big battery packs can be made in a number of ways; I'm using EIG cells like those from older Zero Motorcycles; they just bolt together via wires, busbars, or whatever you want to make, in whatever S and P you like. But the cells are hard to get new, so thankfully they still work well when used, for the ones I have anyway. There's some in the for sale used section, IIRC, though I don't know their condition. I'm using 14s2p, for about 2kwh.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by amberwolf » Oct 28 2018 1:51am

81style wrote:
Oct 24 2018 6:05pm

Even if I end up with the 5kw QS, I'd probably limit it to 3kw max via CycleAnalyst since that's currently the upper limit of my comfort zone.
If you're using a throttle/controller based around torque control vs speed control, you probably won't need to do that.

FWIW, it's nice to have the power when you do need it, like emergency acceleration to get out of the way of traffic that doesn't see you (or doesn't care), when braking would get you killed.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by 81style » Oct 28 2018 11:12am

amberwolf wrote:
Oct 28 2018 1:51am
81style wrote:
Oct 24 2018 6:05pm

Even if I end up with the 5kw QS, I'd probably limit it to 3kw max via CycleAnalyst since that's currently the upper limit of my comfort zone.
If you're using a throttle/controller based around torque control vs speed control, you probably won't need to do that.
Excellent thought. I'll be using a Phaserunner with CA3 in this build, so I'll take a look into the configurations along these lines. Thanks.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by Bg-electric-cycle » Oct 28 2018 11:43am

What front forks are you riding on? I noted the double disc brake. Overall very nice build. :bigthumb:
2WheelsMovesTheSoul wrote:
Oct 25 2018 10:34am
[quote=2WheelsMovesTheSoul post_id=<a href="tel:1420953">1420953</a> time=<a href="tel:1540420024">1540420024</a> user_id=55955]LOL, my EEB is already 148lbs with a 20s14p pack, 18" moto wheels, tubes and tires. Probably end up closer to 165lbs once I get my 22s19p pack.
Heaviest. Build. Ever. Probably... :lol: It was 148lbs last time I weighed it.
KIMG0393[1].JPG
Since then I've added a moto style seat, 80w LED headlight, turn signals, tail light, moto horn, bar end mirrors, a BT audio system, a second DC/DC converter, USB 2a charge port, a bulk charge port with a 50amp Anderson connector, a needle bearing throttle with 0-5v converter, alarm, GPS tracker, dual 1080 DVR, light sensor for automatic headlights, Mudhugger fender, faux fork gaiters and CRF-50 front and rear fender
KIMG0445[1].JPG
Still a work in progress.

Where do you get battery packs that large? Build them. Pulling a range of 60-120a during my rides.

[quote=2WheelsMovesTheSoul post_id=<a href="tel:1420953">1420953</a> time=<a href="tel:1540420024">1540420024</a> user_id=55955]I've pushed over 10k thru mine and with the FF+hubsinks and it hits 60mph with ease.[/quote]

Even if I end up with the 5kw QS, I'd probably limit it to 3kw max via CycleAnalyst since that's currently the upper limit of my comfort zone. I thought the same at first, but my single cylinder KTM makes 63hp and weighs in at 255lbs. I'm used to it. Surprisingly, I prefer the EEB since its so quiet and doesn't rattle my teeth.
[/quote]

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by neptronix » Oct 28 2018 5:35pm

81style wrote:
Oct 19 2018 1:02pm
neptronix wrote:
Oct 19 2018 12:04pm
10lbs more is alot when the bike is already 70lbs.
I actually anticipate that my final build will weigh in at over 100 lbs since I'm using an EEB frame and looking to incorporate the largest battery that will physically fit (upwards of 20s10p).
That's exactly why i like using the lightest motor you can get away with.
It's better to move battery weight than motor weight when modern batteries are still lacking in capacity per kg.

The lightest motor you can get away with can often times be more efficient too, so those big heavy batteries go further.
Currently 20S10P with the highest energy density cell gets you only 2.6kw-hrs.
If you're gonna run a motor at 3kw continuous, the fun comes to an end after a meager ~50 minutes..

Sad reality of a high power build.

4kwhr battery though? now we're talkin.
Efficiency is everything :bolt:

My first major build: 8T MAC motor on a Trek 4500.
The new all-arounder: Leafmotor 1500w on a Turner O2 full suspension.
The monster scooter: ? on a Cannondale Semi Recumbent.

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Re: Hub motor selection guidance: 3kw unbranded vs 5kw QS

Post by Chalo » Oct 28 2018 7:32pm

2WheelsMovesTheSoul wrote:
Oct 24 2018 5:27pm
LOL, my EEB is already 148lbs with a 20s14p pack, 18" moto wheels, tubes and tires. Probably end up closer to 165lbs once I get my 22s19p pack.

If you ain't jumping this bish, get the QS motor, I've pushed over 10k thru mine and with the FF+hubsinks and it hits 60mph with ease.
Who did you find to insure it? Was it hard to get a title for it?
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

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