MXUS 3000 Hub Motor - V1 V2 V3

[arkmundi]

I've searched the forums but came across limited information on good quality downhill rims. Does anyone have other suggestions?

http://www.alexrims.com/ and then buy it through Amazon. Look at the DM24 for instance.

 

[Samd]

As far as brands go, mavic are generally a bit better than alex. Cost a few dollars more accordingly.

A narrower rim will pull the walls in a bit more.

Mavic ex325 is a nice size for a tighter rear swinger. You could also use a maxxis holy roller in a 2.1 width rather than 2.4 if you need a narrower profile versus the 2.5 wide hookies.

 

[molybdenum]

I had exactly the same problem when I first considered going to a 19" and found that the 2.75-19 tire which everyone was getting at the time just wouldn't fit. So I settled for a 2.50 which is fine with modest clearance on both sides.

I am happy I went for it.

I wish my frame would fit a 2 1/2" moped tire at 19"; from my reading here, there is a difference in diameter of at least 1 1/2", which would cause the wide part of my tire to chafe at the narrowing of the frame. Eventually I'll get sick of burning through tires and get a frame without the funny curved chainstay bridge. I'm glad it worked out for you and I can see the advantage of having tougher tires, so I'm definitely on the lookout for a suitable frame.

http://www.alexrims.com/ and then buy it through Amazon. Look at the DM24 for instance.

Unfortunately, amazon.ca is the poor cousin of Amazon.com and doesn't have much in the way of selection. I'd need a US mailing address to order from Amazon.com. I had a look at the DM24 and it has a 32mm profile, as compared with the 36mm of the EX729 I was looking at. I'll see if I can find a supplier with cheap shipping to Canada, as this rim wound certainly be suitable and likely less expensive.

I like the 2.5" tires for the extra shock absorption, as I'm riding a hardtail; even with the 2.5" tires, I'm finding some of the bumps at 60kph somewhat brain jarring. Still, I enjoy having the battery in the triangle, so this seems a suitable compromise.

Mavic ex325 is a nice size for a tighter rear swinger.

I still haven't found this rim in a 36H option; I'll keep looking ,as this seems suitable as well.

Thanks for the input

 

[molybdenum]

Life's full of tradeoffs; yes I have hills and traffic lights but I also have lots of long flat stretches with relatively few lights. I am happy with the 4x15 winding we have ordered.

Also, there are other easy ways to increase torque such as feeding the motor more amps and going to a smaller diameter wheel.

 

[999zip999]

Teslanv I hope you didn't get a bad can of worms as mine came last week and all is fine. Just one dead one on top and two cut in half so eat those fast. So all not so bad with my can of worms.
I'm going to run it in a Alex24 as I have it. I guess 168mm 13-14ga. Spam spokes for it ?

 

[Kent]

Life's full of tradeoffs; yes I have hills and traffic lights but I also have lots of long flat stretches with relatively few lights. I am happy with the 4x15 winding we have ordered.

Also, there are other easy ways to increase torque such as feeding the motor more amps and going to a smaller diameter wheel.

+1 That's why I am going with an 18" moped wheel.

 

[arkmundi]

Teslanv I hope you didn't get a bad can of worms as mine came last week and all is fine. Just one dead one on to and two cut in half so eat those fast. So all not so bad with my can of worms.
I'm going to run it in a Alex24 as I have it. I guess 168mm 13-14ga. Spam spokes for it ?

Zipman, nice to know we're on a similar path. I agonized back & forth between the DM24 and DX32 for awhile before going with the DX32. The DX32 is a half inch wider on the inside, giving a flatter profile to the tire, so more surface, meaning:
1> it has more rolling resistance, so less efficient,
2> it has that much more surface to absorb the bumps & shocks; shock absorption on a bike is by not just a suspension fork, seat post, etc., but also, and firstly and mostly by the tires, tubes, rim & spokes.
The DX32 for me because it has twice the metal in the rim, so is more like a moped rim, reputedly a much stronger rim - the strongest available from Alexrims, I believe. I'm looking for a rim that's going to survive this motor/bike setup with me on it for awhile.

And yes to the Sapim spokes from JHR 13-14 gauage, which I believe will be the best possible match to the MXUS and these rims. I believe your 168mm calculation for a 26" Alex DM24 to be correct, as its what I came up with. Presuming we both have the specs for the motor right - never did get a reliable confirmation on the numbers to my various queries. Nonetheless, I'm about 95% confident in those numbers and spoke length calculations.

See my MXUS Rim & Spokes thread for more detail if any interested.

 

[999zip999]

The hard part with a fat rim is a fat.comoly fame to fit the 2.5 tire ect. Plus will.start out with cellman 12fet. @ 40.amp to start. Maybe 18fet later with more money.
Will this work ?

 

[Motobikewheels]

For you guys that want 19" moto rims let me know the clearance you have and i will see what i can come up with ...street tire or dual sport? I will buy a few to check width if i have to...I would rather know the exact width.

 

[stepan]

Does anyone know if the temperature sensor in this motor (is it KTY83/110?) work with Cycle Analyst v3?
Are there any modifications required to CA like removing/adding internal circuitry, calibration etc?

 

[teklektik]

Yes, it will work fine w/o CA mods. Configure it as a PTC type device.

Use the values in this document KTY-83 series and follow the example for the similar KTY-81/210 in section "5.7 Temperature Sensor" of the Guide.

 

[Samd]

I've been toying with making an aluminium internal stator heatsink out of lasercut 8mm layered sections with different ID's, as an alternative to the later version with the cast stator (because it has a minimum order qty of 400!)

I've yet to open one up to draw it up properly for quoting by my laser cutter, but I want to just get time to lace mine first!!!


Venting will help shed the heat I am sure. But something to act as a thermal shock absorber as well as a heat shedder might be nice.

I'll probably not use mine with long bursts of power anyway, but will let you folks know how I go.

 

[Ebikebert]

Wow! great, I was thinking of the same thing. The more massive the aluminum the longer the motor will take to heat up. Good idea.

 

[ridethelightning]

i was also thinking the same thing, almost.... 8)

perhps a finned heatsink, or several finned plates fixed to both sides of the steel stator core could work well ,especially with venting.

in this case an off the shelf item like the ones in printers/computers could be the goods....just add a little thermo-conductive silicone....a rivot here and there..

 

[Samd]

Nice. I didn't repeat the stack but that was the intention, so the fins would be on every second stack. It may not be obvious in the pic but I cut it into quarters so they'd nest nicely on the sheet for cutting. Should get the cost down.

Did yours arrive yet rtl?

 

[ridethelightning]

@samd
havnt arrived yet. give 'em a couple more days i reckon

 

[John in CR]

Life's full of tradeoffs; yes I have hills and traffic lights but I also have lots of long flat stretches with relatively few lights. I am happy with the 4x15 winding we have ordered.

Also, there are other easy ways to increase torque such as feeding the motor more amps and going to a smaller diameter wheel.

Those aren't other ways. Those are the only ways to increase torque. It's pure myth that the 5x12 winding has more torque than the 4x15. They have the same amount of copper on each tooth, so they are identical motors. You simply run voltage and current proportionately different and performance will be identical. The 5x12 will have higher inductance, making it an easier load on a controller, but that's only a concern with a 2 turn and maybe a 3 turn winding.

Take the supposedly better hill climbing 5x12 motor run at 100V and 50A peak current. With the same size wheel running the 4x15 to get to the same rpm, torque, efficiency, etc simply run it at 80V and 62.5A peak current (and the same proportionately higher phase current limit). The thicker shorter copper of the speedier wind can handle the proportionately higher current. 5000W peak into each motor with identical results.

If you want to climb hills better, then more torque is needed, and the best way to do that is by decreasing the wheel size.

The real beauty of speed wind motors is due to voltage being our practical limitation. The above example makes the difference clear. Using reasonably priced controllers the 5x12 is maxed out other than to try to stuff more current into it, which it handles less well. Decreasing wheel size is always good, but that decreases speed for the 5x12. To keep the numbers round let's say you were looking at running a wheel with an OD of 25". With the 4x15 you can decrease the wheel size to 20" for a 20% increase in torque, and then increase voltage to 100V to put you back to the same speed. Not only do you get more torque to be able to climb a steeper hill, but you also have more power 6250W peak input, so you can climb hills faster. The decreased load of the motor sees with the lower gearing, means the motor will run more efficiently, at reduced stress, and the higher rpm means better cooling too. Better cooling and better efficiency means a cooler motor, and that too adds a bit more efficiency as well.

Wait it still gets better. Let's say the guy running the 4x15 in the 20" wheel knows that his buddy with the 5x12 wind in a 25" wheel isn't having heat issues running his at 5kw peak input, and they run the same total load with similar riding, so he's willing to run his 4x15 at the same stress levels. That means he can boost current even higher, probably to 70 or 80A without issue. So now he's running the same weight and price motor at 7-8kw, and putting his system under no more stress than the poor guy who ordered the 5x12 motor and can only run at 5kw. Who do you think will have the bigger EV grin when they ride together? Sure it's a little harder to make that 20" wheel look as good on the bike, but with hubmotors those who value looks over performance get stuck with the lower performance resulting.

How do you guys think I've been running my cargo bike for almost 6 years with a 60mph top speed on 74V nominal with my wide body load in a mountainous country? No, it's not because it has a bigger motor. It's got a stator and magnets that are identical to an Xlyte H40, but with a 2 turn wind and a 14" moto wheel that ends up just under 20" OD.

Note that the above discussion doesn't mention iron losses, which increase with rpm. They're pretty minor though up to about 1krpm with common high slot count motors. To verify how small it is, take your motor before it gets laced and measure the no-load current at different rpms at the high end of the scale. The difference in no-load current X voltage is how much more iron losses you have, and to make the comparison you don't want the wind resistance of wheel and spokes giving you misleading results.

John

 

[edventure]

Wow! great, I was thinking of the same thing. The more massive the aluminum the longer the motor will take to heat up. Good idea.

Also, the longer it will take to shed some of that heat

 

[chucho]

Life's full of tradeoffs; yes I have hills and traffic lights but I also have lots of long flat stretches with relatively few lights. I am happy with the 4x15 winding we have ordered.

Also, there are other easy ways to increase torque such as feeding the motor more amps and going to a smaller diameter wheel.

Those aren't other ways. Those are the only ways to increase torque. It's pure myth that the 5x12 winding has more torque than the 4x15. They have the same amount of copper on each tooth, so they are identical motors. You simply run voltage and current proportionately different and performance will be identical. The 5x12 will have higher inductance, making it an easier load on a controller, but that's only a concern with a 2 turn and maybe a 3 turn winding.

Take the supposedly better hill climbing 5x12 motor run at 100V and 50A peak current. With the same size wheel running the 4x15 to get to the same rpm, torque, efficiency, etc simply run it at 80V and 62.5A peak current (and the same proportionately higher phase current limit). The thicker shorter copper of the speedier wind can handle the proportionately higher current. 5000W peak into each motor with identical results.

If you want to climb hills better, then more torque is needed, and the best way to do that is by decreasing the wheel size.

The real beauty of speed wind motors is due to voltage being our practical limitation. The above example makes the difference clear. Using reasonably priced controllers the 5x12 is maxed out other than to try to stuff more current into it, which it handles less well. Decreasing wheel size is always good, but that decreases speed for the 5x12. To keep the numbers round let's say you were looking at running a wheel with an OD of 25". With the 4x15 you can decrease the wheel size to 20" for a 20% increase in torque, and then increase voltage to 100V to put you back to the same speed. Not only do you get more torque to be able to climb a steeper hill, but you also have more power 6250W peak input, so you can climb hills faster. The decreased load of the motor sees with the lower gearing, means the motor will run more efficiently, at reduced stress, and the higher rpm means better cooling too. Better cooling and better efficiency means a cooler motor, and that too adds a bit more efficiency as well.

Wait it still gets better. Let's say the guy running the 4x15 in the 20" wheel knows that his buddy with the 5x12 wind in a 25" wheel isn't having heat issues running his at 5kw peak input, and they run the same total load with similar riding, so he's willing to run his 4x15 at the same stress levels. That means he can boost current even higher, probably to 70 or 80A without issue. So now he's running the same weight and price motor at 7-8kw, and putting his system under no more stress than the poor guy who ordered the 5x12 motor and can only run at 5kw. Who do you think will have the bigger EV grin when they ride together? Sure it's a little harder to make that 20" wheel look as good on the bike, but with hubmotors those who value looks over performance get stuck with the lower performance resulting.

How do you guys think I've been running my cargo bike for almost 6 years with a 60mph top speed on 74V nominal with my wide body load in a mountainous country? No, it's not because it has a bigger motor. It's got a stator and magnets that are identical to an Xlyte H40, but with a 2 turn wind and a 14" moto wheel that ends up just under 20" OD.

Note that the above discussion doesn't mention iron losses, which increase with rpm. They're pretty minor though up to about 1krpm with common high slot count motors. To verify how small it is, take your motor before it gets laced and measure the no-load current at different rpms at the high end of the scale. The difference in no-load current X voltage is how much more iron losses you have, and to make the comparison you don't want the wind resistance of wheel and spokes giving you misleading results.

John

Thank so much for sharing your wisdom it is allways a pleasure reading from you!
And yes... using 20" on this motor was my plan

 

[teslanv]

I agree that a 4X15 winding and a 5X12 winding will perform identically when Voltage and Current are adjusted proportionately. I have to point out that it is Current that (mainly) causes heat, and if the intent is to keep the heat at reasonable levels for a given total power, it will be better to have higher voltage and lower current for an equivalent amount of power. That bodes better for the Slower wind motor. Given the same total power output a 5X12 should run cooler than a 4X12 motor, since the 5X12 is using higher voltage and less current to achieve the same power output.

Also, the 5X12 turn motor will produce the required thrust from lower current from a stop or going up a hill, than will a 4X15 if voltage is a constant (limited). Since many of us are limited to ~100V by the common 4110 FETs, this is one advantage the 5X12 wind has over the 4X15. - Better starting and hill climbing ability as compared the faster wind motor.

 

[arkmundi]

Given the same total power output a 5X12 should run cooler than a 4X12 motor, since the 5X12 is using higher voltage and less current to achieve the same power output... Also, the 5X12 turn motor will produce the required thrust from lower current from a stop or going up a hill, than will a 4X15 if voltage is a constant (limited). Since many of us are limited to ~100V by the common 4110 FETs, this is one advantage the 5X12 wind has over the 4X15. - Better starting and hill climbing ability as compared the faster wind motor.

Alright, thanks. I don't have a clue and appreciate your & other's patient explanations of the differences we can expect. I'm equally happy with my 5-wind, understand the order has been finalized and will get that. So be it!

 

[teslanv]

I ran two simulations with a 2805 and a 2808 to show the comparison.
All other fields are the same. 100V Battery, 40A 4110 controller, aero, weight, slope.

What you will see is the primary difference between the motors is the speed on level grade and power required to maintain that speed on level grade.

The 2805 motors requires more power and is less efficient (albeit at a higher speed) on level grade than a "slower" wind motor.

It really just boils down to how fast you will ride and how efficient you will be at your preferred speed.

For me, I think the 5X12 will be a more efficient motor at the power level, speeds and terrain I will be riding.
[edit] I added a third simulation with the 2805 wind motor, but this time with the throttle reduced to 64% so as to match (as close as I could) the speed of the 2808 wind motor. You will notice the performance is very close to the same. - Which seems to confirm John's assertion that the performance is the same, given similar total power. - However notice the difference in motor amps on the 2805 vs the 2808. This is due to the fact that by easing off the throttle on the 2805 motor, you are effectively lowering the voltage that the motor sees, so to make up for the lower effective voltage, more amps are required to run the 2805 motor at the same speed as the 2808 motor at full throttle, and thus you should expect higher temperatures in the 2805 motor.

 

[Punx0r]

I have to point out that it is Current that (mainly) causes heat

Are you sure?

I make it Power(heat) = IV

Or I^2R, where R = V/I

 

[teslanv]

Take a 12ga copper wire and run 3000W of power though it two different ways. 100V @ 30A or 300V @ 10 amps. See which method gets the wire hotter.
This is why power companies run their Primary power lines at High Voltage - so they can transmit massive amount of total power at low current and not overheat the cables.

 

[madin88]

@ John

you have right. same motor = same nominal rated torque and rpm. no matter what turn count it has (if copper fill remains the same).

the problem is to find a controller which is able to put out those required higher amps with good efficiecny to have equal torque like a higher turn count motor.
If i could choose between low volt / high amp and high volt / low amp i would prefer the latter. Also less heat generated in all wires and connectors.

Smaller wheels will keep efficiency and acceleration high, but the smaller the wheel, the less comfortable the bike becomes. Mainly traction on bumpy street is poorer with smaller wheels. The bike may be capeable of high speed on the flat, but you are not able to ride it like a motorcycle lean into corners because you will loose traction and crash.