Any experience with the QS 17x4.5 12-14KW liquid cooled hub motor?

[E-GSX]

After sizing my project for battery space, I'm considering using a hub motor vs the existing shaft drive on my GSX1100G. The 9" diameter x 14" long 80KW direct drive motor has several drawbacks:
1) It looks to be really expensive ($5,400 motor & controller) vs about $2,300 for the 17x4.5 12~14KW below.
2) It would require a u-joint to mate the bike's shaft drive to the motor shaft. While I'm sure this could be fabbed, it's an additional cost.
3) The motor (or even a smaller diameter/shorter one) eats up room I need for batteries. Since my bike has an upper & lower fairing, I am limited on how wide a battery pack can stick out up front.

The most common 12KW version hub drive comes on a 17x6.0 width rim. I have a nearly new 160/70-17 rear tire on the bike, but from what I've read it can only be used up to 5.5~5.75" wide rims. The minimum size shown on the QS site is 180/55, which is a shorter & wider tire. AFAIK, my OEM rim is 4.5~5" wide (caliper measurement on outside of rim bead area but not the widest part). A basic search showed the common 17" hub motor rims are either 3.5" for the 3KW~8KW or 6" for the 10KW/12KW.

While I was typing this, I saw QS Motor is a member here and had a hub drive thread that began in 2015. I saw there was a "new" 17x4.5 12KW fluid cooled hub motor, and apparently there was/is a 14KW version. The hyperlink there didn't work, but I found a current listing on Ali Express that says it is no longer available:
https://www.aliexpress.us/item/2251832816692903.html?gatewayAdapt=glo2usa4itemAdapt. There is a listing on Alibaba.

Specs are favorable for my application. Fluid cooling for the motor and if needed for the controller would be relatively easy since my bike has a large oil cooler up front (Suzuki Advanced Cooling System). It's also rated for higher speed (170KMH or 105MPH) than the 6" version. I'd like to find out if anyone here has used this particular hub drive.

Finally, I'd like to find out of this 12~14KW motor would be sufficient for 800 pounds of rider and bike at freeway speeds (70-80 MPH sustained). The specs on the QS site for both versions claim torque of 200 – 350N.m, which is far more than my 1127cc ICE ever made (99 peak).

 

[dominik h]

Your GSX1100 Motor has 99Nm at the crank, and with the gearbox and the final drive you get about 300-800Nm at the wheel, depending on which gear you drive.

 

[E-GSX]

Thanks. Writing a spreadsheet using the gear/primary/secondary/final ratios and data from a similar Suzuki engine's dyno sheet, I get a range of around 400-768 NM. I input 1500 RPM for 1st gear to get it moving & that was around 512. I'm not super concerned about acceleration, so I'll continue to look into this. I'm not sure this hub motor is still made, so it may be a moot point.

EDIT- Heard from QS, it's discontinued.

 

[dominik h]

Google says YM has a 15kw and a 20kW 17" hub motor without water cooling.
But I think they are also 6" wide and I can't find any datasheets.

 

[dominik h]

TingTong Motor has also announced a watercooled hub motor with up to 57kw peak

 

[E-GSX]

Thanks, that's why I joined here, to learn about other possibilities. I see that site also sells higher power mid drive type motors. I can't get the site to load entirely in English though.

 

[dangerzone]

After sizing my project for battery space, I'm considering using a hub motor vs the existing shaft drive on my GSX1100G. The 9" diameter x 14" long 80KW direct drive motor has several drawbacks:
1) It looks to be really expensive ($5,400 motor & controller) vs about $2,300 for the 17x4.5 12~14KW below.
2) It would require a u-joint to mate the bike's shaft drive to the motor shaft. While I'm sure this could be fabbed, it's an additional cost.
3) The motor (or even a smaller diameter/shorter one) eats up room I need for batteries. Since my bike has an upper & lower fairing, I am limited on how wide a battery pack can stick out up front.

The most common 12KW version hub drive comes on a 17x6.0 width rim. I have a nearly new 160/70-17 rear tire on the bike, but from what I've read it can only be used up to 5.5~5.75" wide rims. The minimum size shown on the QS site is 180/55, which is a shorter & wider tire. AFAIK, my OEM rim is 4.5~5" wide (caliper measurement on outside of rim bead area but not the widest part). A basic search showed the common 17" hub motor rims are either 3.5" for the 3KW~8KW or 6" for the 10KW/12KW.

While I was typing this, I saw QS Motor is a member here and had a hub drive thread that began in 2015. I saw there was a "new" 17x4.5 12KW fluid cooled hub motor, and apparently there was/is a 14KW version. The hyperlink there didn't work, but I found a current listing on Ali Express that says it is no longer available:
https://www.aliexpress.us/item/2251832816692903.html?gatewayAdapt=glo2usa4itemAdapt. There is a listing on Alibaba.

Specs are favorable for my application. Fluid cooling for the motor and if needed for the controller would be relatively easy since my bike has a large oil cooler up front (Suzuki Advanced Cooling System). It's also rated for higher speed (170KMH or 105MPH) than the 6" version. I'd like to find out if anyone here has used this particular hub drive.

Finally, I'd like to find out of this 12~14KW motor would be sufficient for 800 pounds of rider and bike at freeway speeds (70-80 MPH sustained). The specs on the QS site for both versions claim torque of 200 – 350N.m, which is far more than my 1127cc ICE ever made (99 peak).

The GSX1100G is one of the bikes I own. It has a massive torque, hence Suzuki opted for a hydraulic clutch so that the bike would not wheelie and put too much stress on the gears and shaft drive. The engine is restricted, it has around 100HP but can be tuned to have over 200HP without adding boost (turbocharger or compressor) if the head is remachined.

You could not get that much power from the Chinese factory made radial hub motors or mid drives. Their torque and power specs are often overrated, providing info for peak power instead of continuous power. Yuma does have a 25kW continuous motor, QS seems to be lagging behind last time I tried to ask for a custom made hub motor.

The torque from your engine is at the crankshaft, hence your bike will have around 800Nm (Newton-meters) in first gear at the wheel when your rpm is at the top of the torque curve (roughly at 8000 to 8500 rpm). There is no way a radial electric motor like the ones produced by QS or Yuma could have that much power or torque, this is axial hub motor range.

Axial hub motors could be as light as 12kg to 25kg and produce 60kW continuous to 250kW peak with torque which could outperform any ICE on the market and match a turbocharged Hayabusa. However, the price for such a motor is an order of magnitude higher than what you have available in China or elsewhere, most are custom made.

Most high performance bike manufacturers from Europe like Energica or KTM simply stack a couple of shaft driven electric motors and pair them to reach the desired torque and power, then transfer that with a chain to the rear sprocket. They do that because it is simpler and cheaper. The bikes with hub motors have better performance, but are twice as expensive.

In the end it comes down to what you want to acheive. The water cooling is a complexity which is good for very demanding mission requirements. You would be better off with a well designed concept and powerful batteries than water cooling. The 12kW hub motor would not be enough for continuous freeway speeds of 70mph to 80mph of 400 pounds of mass.

However, a 25kW continuous motor would. I am following what the Chinese are able to do, and it is possible that in two to five years they might be able to come to that level of cheap engineering. The newest 25kW Yuma motor is proof of the concept in a 13 inch wheel rim, we will see if QS can match a similar product which would be bellow the $900 or 900€ level.

Why 900 and not a thousand, you may ask? Because you have to calculate at least a hundred buck to resolve all the quality control and other issues before your hub motor or anything that comes from China becomes fully functional. I am writing from experience, they can make good motors but you need to take care of all details.

 

[E-GSX]

Thanks for all that info. First, I don't see ever hitting 8K RPM in 1st gear. Next the GSX motor makes peak torque of 99 Nm around 4,750. I wrote out a spreadsheet with the primary/secondary/ each gear in the trans and final drive ratios. With 99 Nm @ 4,750 RPM, in 1st gear the rear wheel would see a whopping 1,272 Nm. Again, that's an unreal situation since no one that daily rides launches at 4,750 RPM to take off from a stop. At a more realistic 25 Nm (the dyno chart I saw for a similar GSX1100F didn't go below 2K RPM) for a 1,500 RPM launch, this figure drops to 321. With the OEM motor, in 5th gear at 4,750 I had 449 Nm at the rear wheel. The peak rolling (realistic) RW torque for 2nd, 3rd, and 4th were 845, 658, and 552 respectively.

I agree with you the hub motor won't work here, plus the one sold that is 17 x 6" wide is too wide for me. The 3.5" one is no longer sold, so moot point.

I'm currently looking at the new SiA 200-50 gear reduction "hairpin" motor. It has an internal 2.5:1 reduction and is capable of a steady 12kW (max of 28kW) @ 72V, but is supposed to be highly under rated. The smaller 4kW rated QS138 90H V3 for example is supposed to handle 20kW with no problem. This motor @ 72V outputs 175 Nm at the shaft. At 72V, I estimate since all I've have behind that is a 2.67:1 final drive, that I'll see 467 Nm at the rear wheel. At 96V, I estimate this figure to be around 233 shaft for 622Nm RW. If for some reason this does not work, I can use it with a belt drive system presuming I can get a splined adapter made for my rear wheel. For a battery pack, I'm looking at the 4695 cell, which in 26S8P would give me over 20kWh from a pack that fits into the frame.

I'm not buying anything anytime soon, so I'll keep learning and watching the market as things progress.

 

[Scootdan]

The GSX1100G is one of the bikes I own. It has a massive torque, hence Suzuki opted for a hydraulic clutch so that the bike would not wheelie and put too much stress on the gears and shaft drive. The engine is restricted, it has around 100HP but can be tuned to have over 200HP without adding boost (turbocharger or compressor) if the head is remachined.

You could not get that much power from the Chinese factory made radial hub motors or mid drives. Their torque and power specs are often overrated, providing info for peak power instead of continuous power. Yuma does have a 25kW continuous motor, QS seems to be lagging behind last time I tried to ask for a custom made hub motor.

The torque from your engine is at the crankshaft, hence your bike will have around 800Nm (Newton-meters) in first gear at the wheel when your rpm is at the top of the torque curve (roughly at 8000 to 8500 rpm). There is no way a radial electric motor like the ones produced by QS or Yuma could have that much power or torque, this is axial hub motor range.

Axial hub motors could be as light as 12kg to 25kg and produce 60kW continuous to 250kW peak with torque which could outperform any ICE on the market and match a turbocharged Hayabusa. However, the price for such a motor is an order of magnitude higher than what you have available in China or elsewhere, most are custom made.

Most high performance bike manufacturers from Europe like Energica or KTM simply stack a couple of shaft driven electric motors and pair them to reach the desired torque and power, then transfer that with a chain to the rear sprocket. They do that because it is simpler and cheaper. The bikes with hub motors have better performance, but are twice as expensive.

In the end it comes down to what you want to acheive. The water cooling is a complexity which is good for very demanding mission requirements. You would be better off with a well designed concept and powerful batteries than water cooling. The 12kW hub motor would not be enough for continuous freeway speeds of 70mph to 80mph of 400 pounds of mass.

However, a 25kW continuous motor would. I am following what the Chinese are able to do, and it is possible that in two to five years they might be able to come to that level of cheap engineering. The newest 25kW Yuma motor is proof of the concept in a 13 inch wheel rim, we will see if QS can match a similar product which would be bellow the $900 or 900€ level.

Why 900 and not a thousand, you may ask? Because you have to calculate at least a hundred buck to resolve all the quality control and other issues before your hub motor or anything that comes from China becomes fully functional. I am writing from experience, they can make good motors but you need to take care of all details.

Good day sir. I have really enjoyed reading and learning from what you have written here. I was just wondering if you have any thoughts on 2wd cycles. I have built this big scooter and it seems to be very fast and quick and really efficient for the amount of power I have compared to the huge power you guys are talking about here. I am just a newcomer and still learning my way, so your opinion would be much appreciated. I have two 72v. 87ah batteries which I was told are about 5kW each, and two QS 12kW hub motors and 680 amp controllers . I think my 0 to 60 is around three seconds and it cruises effortlessly at 70 + mph on the highway. Range looks around 100 miles at normal speeds, maybe 60 miles at real freeway speed. The acceleration seems just intense to me, even near top speed, but you would probably have a better perspective on it sir, Thank you.

 

[amberwolf]

I have two 72v. 87ah batteries which I was told are about 5kW each,

That sounds odd. 72v x 87Ah = about 6200Wh (6.2kWh). if you can only draw 5kW, that's less than 1C, which for "EV" batteries is terrible (not too uncommon for laptop / vape batteries made of low-power 18650 cells, though).

It's also only 5kW (5000W) / 72v = 69A. So if you're using:

and two QS 12kW hub motors and 680 amp controllers

Then at peak you're drawing ten times the current those batteries can handle, which should heat them quite a lot, and probably damage them quickly, if that's drawn very often. But even low acceleration would probably draw more than 69A per battery, especially at the speeds you're talking about.

So...I think something in the battery specs you have must not be correct. Do you have a link to the place the batteries came from that gives detailed specs on them?

 

[Scootdan]

That sounds odd. 72v x 87Ah = about 6200Wh (6.2kWh). if you can only draw 5kW, that's less than 1C, which for "EV" batteries is terrible (not too uncommon for laptop / vape batteries made of low-power 18650 cells, though).

It's also only 5kW (5000W) / 72v = 69A. So if you're using:



Then at peak you're drawing ten times the current those batteries can handle, which should heat them quite a lot, and probably damage them quickly, if that's drawn very often. But even low acceleration would probably draw more than 69A per battery, especially at the speeds you're talking about.

So...I think something in the battery specs you have must not be correct. Do you have a link to the place the batteries came from that gives detailed specs on them?

Hey amberwolf, thanks for the input. So sounds like my 5kW battery number is bad. They say these batteries are 6C and they are hella powerful. I run the scooter at freeway speed for over a half hour and only the controllers get even a little warm. So the battery power is rated from C output also? These say 6C continuously, 12C max pulse. So you are a great person to ask here, have you seen other people running running two wheel drive cycles on the street?

 

[amberwolf]

Hey amberwolf, thanks for the input. So sounds like my 5kW battery number is bad. They say these batteries are 6C and they are hella powerful. I run the scooter at freeway speed for over a half hour and only the controllers get even a little warm. So the battery power is rated from C output also? These say 6C continuously, 12C max pulse.

The C rating is a wierd number, because capacity and current capability are not actually directly related parameters, but the definition of C rate implies that they are. What it means is that, for any specific cell, the number given before C is multiplied by the capacity in Ah of the cell (or battery if the C rate is for an entire pack), to give an A number (current capability).

So for a 6C cell, to know what current it can do, you'd need the cell Ah to multiply by. Your pic shows 87.5Ah, which means 6 x 87.5 = 525A.

The 12C pulse (for how long (pulse length), and how often (duty cycle)?) would be twice that.


BTW: what you're showing are cells, which is different than what the battery full of them can do. What the battery can do is limited by the wiring and connectors into the battery pack itself, interconnections between cells, number of parallel cells (if any), and the BMS (if any).

So, if you have only a 1P pack, then it's max continuous current (assuming all items in series with the cells can do this) is 525A. It's max pulse is twice that.

I couldn't find info on what your present BMS can do; a previous one you used (if it's not the same) was only 100A, and if your new one isn't better than 100A is your limit, beyond which the BMS should turn off the output and shutdown your system completley from total loss of input voltage and current from the battery.

Whatever your BMS current limit is, that's what should happen beyond it. If it doesn't, then your BMS is not doing it's job either because it's defective or has failed or is wired wrong so that it can't actually disconnect the output from the cells.

Some BMS have a "soft" limit range in which it waits a certain amount of time before doing that, but above which it has to do it instantly or else be damaged or allow cell damage.


Assuming everything in there is capable of 525A, then at nominal 72v that's 72 x 525 = 37800W continuous.

If it's all capable of the pulse current, then you could have twice that power for however long the cells and other parts are rated to be used at that.

So you are a great person to ask here, have you seen other people running running two wheel drive cycles on the street?

Around here where I live, rarely.

For myself, both of my most-used builds, CrazyBike2 and SB Cruiser trike, have been 2WD for most of their useful lifespans, and bicycles have always been my only transportation (excepting very very rare rides from other people, less than once a year typically). The future SBC MkII trike and Cloudwalker Cargo Bike, if ever built, will probably also be 2WD or AWD.

Here on the forums, there are a number of 2WD+ / AWD builds of bicycles, scooters, etc., with their own threads you can probably find using those as search terms in thread titles. How they're used outside of whatever is in their threads I don't know.

 

[Scootdan]

The C rating is a wierd number, because capacity and current capability are not actually directly related parameters, but the definition of C rate implies that they are. What it means is that, for any specific cell, the number given before C is multiplied by the capacity in Ah of the cell (or battery if the C rate is for an entire pack), to give an A number (current capability).

So for a 6C cell, to know what current it can do, you'd need the cell Ah to multiply by. Your pic shows 87.5Ah, which means 6 x 87.5 = 525A.

The 12C pulse (for how long (pulse length), and how often (duty cycle)?) would be twice that.


BTW: what you're showing are cells, which is different than what the battery full of them can do. What the battery can do is limited by the wiring and connectors into the battery pack itself, interconnections between cells, number of parallel cells (if any), and the BMS (if any).

So, if you have only a 1P pack, then it's max continuous current (assuming all items in series with the cells can do this) is 525A. It's max pulse is twice that.

I couldn't find info on what your present BMS can do; a previous one you used (if it's not the same) was only 100A, and if your new one isn't better than 100A is your limit, beyond which the BMS should turn off the output and shutdown your system completley from total loss of input voltage and current from the battery.

Whatever your BMS current limit is, that's what should happen beyond it. If it doesn't, then your BMS is not doing it's job either because it's defective or has failed or is wired wrong so that it can't actually disconnect the output from the cells.

Some BMS have a "soft" limit range in which it waits a certain amount of time before doing that, but above which it has to do it instantly or else be damaged or allow cell damage.


Assuming everything in there is capable of 525A, then at nominal 72v that's 72 x 525 = 37800W continuous.

If it's all capable of the pulse current, then you could have twice that power for however long the cells and other parts are rated to be used at that.



Around here where I live, rarely.

For myself, both of my most-used builds, CrazyBike2 and SB Cruiser trike, have been 2WD for most of their useful lifespans, and bicycles have always been my only transportation (excepting very very rare rides from other people, less than once a year typically). The future SBC MkII trike and Cloudwalker Cargo Bike, if ever built, will probably also be 2WD or AWD.

Here on the forums, there are a number of 2WD+ / AWD builds of bicycles, scooters, etc., with their own threads you can probably find using those as search terms in thread titles. How they're used outside of whatever is in their threads I don't know.

I really appreciate your help understanding the C rate and more about power numbers Amberwolf, thank you very much. So originally my scoot only had one battery with a 100 amp BMS feeding both hub motors. Now it has two batteries, one for each motor, and each with a 150 amp BMS. Lots of power. I was thinking you had probably seen most kinds of builds to drift through here and might have some firsthand experience. I will have to search the threads soon and see what’s going on with 2WD now. I just can’t get over the acceleration! Best wishes.

 

[amberwolf]

So originally my scoot only had one battery with a 100 amp BMS feeding both hub motors. Now it has two batteries, one for each motor, and each with a 150 amp BMS. Lots of power.

If the BMS is only 150A, then that means either it can only physically handle 150A and would be damaged by more than that, or it would shutdown at more than 150A (possibly after some very short period of time).

If your controllers are not limited to only 150A to match that, then either:
-- you're getting shutdowns, or
-- something is wired wrong so that the BMS discharge port is being bypassed, or
-- the BMS is damaged in a way that prevents it from being able to shutoff the output for *any* reason, ever***, or
-- the BMS is actually set to or rated as high as the controller's current limit, or
-- the controllers are never drawing more than 150A,
-- etc.


I think it might be important to verify which of those things is true, before you end up with cell damage from some preventable exceeded-limit, if one of the things that allows that is true.


***which isn't that uncommon, and is probably more common than it seems since there's no way to even know this damage has happened unless you physically test to see if it can shut off the output, and verify that it does indeed do so, so there's likely quite a few packs out there with fried BMS that can't protect the pack against damage because the BMS itself is damaged with shorted FETs.

There's a thread around here by Methods detailing testing done on some Daly BMS that failed in this way, leaving them unable to protect anything anymore (making them not only useless, but dangerous, since the user doesn't know it's happened, and thinks the protection is still in place. )

 

[amberwolf]

I was thinking you had probably seen most kinds of builds to drift through here and might have some firsthand experience.

I do, which I posted about.

It was a general answer to a general question ("So you are a great person to ask here, have you seen other people running running two wheel drive cycles on the street?").

If you need specific information you'd have to ask specific questions.

But all of this is far off topic from the thread, and if you don't mind, I'd like to move it all over to your most recent thread about your project.

 

[Dui ni shuo de dui]

You could not get that much power from the Chinese factory made radial hub motors or mid drives. Their torque and power specs are often overrated, providing info for peak power instead of continuous power.

If I may, I'd just like to say that this is exactly the same for every gas engine as well, when you say your bike has 100hp it is only true for a very short range of rpm and you can't let it run at that kind of power for very long without risking serious damage to it.
The only kind of engine for which it is possible to talk about continuous power are diesels, at least to my knowledge.

Also, in my experience, the ratings provided by chinese motor manufacturers are usually way underrated (at least for QS, I haven't experimented with other brands). For instance, I've been running my 3KW motor for almost 10 years at power levels ranging from 16 to 25KW. Same with my scooter's 2KW hub which takes around 22KW with my current settings. These motors are still in perfect condition today and I'm using them everyday