Definitive Tests on the Heating and Cooling of Hub Motors

[Offroader]

I think that first of all we should try using the right winding in the motor based on the riding style.
If you constantly accelerating from 10km/h to 30-50km/h and your riding style is mostly like that while using a 4t mxus then you know that your motor only gives you 20-30% efficiency (roughly speaking)

Based on that, going to say a 6T motor will probably have a lot more efficiency at those speeds while at the same time you don't have to use such high phase amps to get the same amount of torque - in result a lot less heat.
So why use a motor that has 90% efficiensy at 80km/h when you almost don't ride around at that speed and instead getting only 30-40% ?
I do believe that you can have a lot less issues going this path.

Yeah but you know the deal, we all need to do 100KPH.

 

[Hummina Shadeeba]

I thought heat was proportional to torque and with the higher kv the windings will needing more amps but they have less resistance

 

[burningwings]

Thanks Offroader for your comments ! I liked the term " stress test " reminded me of my medical stress test for my heart . A resting heart or an idling engine are not very useful functional tests . I don't spend all my rides going from 0 to 30 mph at WOT , but I did experience thermal shutdown after some spirited in town ridding ! Power transformers are cooled by oil . Soybean oil and mineral oils are used . The physical construction of motor wingdings and stator cores are virtually the same as transformers with similar causes for heating . So does oil cooling work ? Keeping the lights on from Maine to Spain . If sealed bearings or automotive type oil seals on the shaft could be employed , hub fins and oil filling is surely a simple effective way of cooling the motor . With 3250 miles of Sacramento rough roads and a solid rear frame , my bearings might have lost the ability to prevent oil leaking out through them .

 

[Offroader]

Thanks Offroader for your comments ! I liked the term " stress test " reminded me of my medical stress test for my heart . A resting heart or an idling engine are not very useful functional tests . I don't spend all my rides going from 0 to 30 mph at WOT , but I did experience thermal shutdown after some spirited in town ridding ! Power transformers are cooled by oil . Soybean oil and mineral oils are used . The physical construction of motor wingdings and stator cores are virtually the same as transformers with similar causes for heating . So does oil cooling work ? Keeping the lights on from Maine to Spain . If sealed bearings or automotive type oil seals on the shaft could be employed , hub fins and oil filling is surely a simple effective way of cooling the motor . With 3250 miles of Sacramento rough roads and a solid rear frame , my bearings might have lost the ability to prevent oil leaking out through them .

If you need new bearings you may want to try these Nachi bearings. They may seal out the oil better, but who knows. They cost just a little more than the china bearings, and you are getting Japan made bearings.

Would be interesting if you used one of those pressure valves like madin88 mentioned to see if that helps any.

I picked up those Nachi bearings for my cromotor, so you will have to see if they have the size for your motor. They may not.

https://cnc-specialty-store.com/bearings/ball-bearing/6204-2nse-nachi-bearing-20x47x14-sealed-c3?zenid=4b8e72df88976c403f697a2730ee29f6

 

[burningwings]

These bearings look like they could be the answer . Looks like they have a rubber seal around inner diameter where the axle passes through . I will check them out in the near future . Thanks !

 

[DasDouble]

@the guy who wanted to test ff:

here is a small video I have found when I was searching for the name of the black coloure to spray your motor side covers with:

[youtube]QerQ5B-8DfQ[/youtube]

 

[burningwings]

Thanks Offroader I ordered the bearings you suggested only cost $ 22 dollars delivered ! Got the size form the Grin web site 17mm x 40 mm for all H Crysolite motors !

 

[sketchism]

But I have also another idea: Some sort of shovels on the holes of the side cover. This way, the sidecover would function as a big fan as it "shovels" the air inside through itself like a big fan
If this isn´t a good idea then I just dont know what to say anymore.. When I think about it twise I just realize this idea is perfect as the radius is just as big as possible which supports a bigger air flow! Means: The bigger the wholes = shovel of every single hole + the further away every single hole is from the axle, the bigger the air flow! Why did no one else come to this idea before????

GENIOUS!

That sounds like the idea sam dekok had last year, i actually had them fitted to one of my motors for a test with 25mm holes, i can't find the photos of it but it looked how you'd expect.
i didn't mind it and the idea was good

i placed them on one side with exit holes on the other, and while it did work much better than an unvented hub as expected, it was only 5% or so more effective than a vented hub and by then the hubsinks prototypes were on my other motors and performing roughly 200% better with the Fins and Statoraide than venting was, in all subsequent builds i've dropped venting all together (only because it wasn't necessary i never really had an issue with dirt or junk getting in even though we ride 90% steep & fast offroad)

 

[Samd]

Man I must try some of those venturis. Like so many of my unfinished ideas. Unfinished

Heres the 3d laser sintered aluminium ones sketch and i were playing around with models for at the start of may last year

Anyone is welcome to take the 3d files for free and reprint on shapeways.

https://drive.google.com/file/d/0B9yGWuHxeLnjamIzQWhPMXczRWs/view

Ironically it was while pissing around in 3d on that day a year ago today that i dropped this concept on the facebook chat screen! Little did i know! That 3d model is still sitting on shapeways servers. So expensive.

It made sense to pursue the hubsink as a concept. Sand bugs and shit inside your hub via venturis is not as good an idea. Take it from a guy with an eng degree. Air is an awful thermal carrier.

From what I can see crossbreak seems to have been the first to propose using ferrofluid based on subwoofer cooling. It has much better thermal transfer than air. Then it becomes vital to get the heat away from the magnet ring to prevent degaussing. Thats where sketch's product is vital.

In combination its unbeatable.


Sent from my iPhone using Tapatalk

 

[ninepointeight]

Regrettably I have not yet read this entire thread, but I'm wondering if anyone knows the difference between the ferrotec audio grade ferrofluid that is sold at ebikes.ca and their "educational" ferrofluid sold on amazon, at a mere fraction of the price. They both seem to be magnetic nanoparticles suspended in synthetic oil?
Ferrotec lists the carrier liquid for the audio grade ferrofluid as "synthetic hydrocarbon" as opposed to the educational version as "light hydrocarbon". Any ideas as to what the difference is? Anyone tried the educational stuff in their motor?

 

[parabellum]

Regrettably I have not yet read this entire thread, but I'm wondering if anyone knows the difference between the ferrotec audio grade ferrofluid that is sold at ebikes.ca and their "educational" ferrofluid sold on amazon, at a mere fraction of the price. They both seem to be magnetic nanoparticles suspended in synthetic oil?
Ferrotec lists the carrier liquid for the audio grade ferrofluid as "synthetic hydrocarbon" as opposed to the educational version as "light hydrocarbon". Any ideas as to what the difference is? Anyone tried the educational stuff in their motor?

It evaporates quickly and even quicker at higher temperatures. Basically, you will have useless, magnetically active dust after a while.

 

[bigbore]

Ferrofluid leaking
I've been using Statorade ferrofluid from a year now and yesterday I noticed that the oil found the way to pass trough the thermal paste that I used when I put the oil inside the motor.
This is what I used to seal the side covers:
http://www.ebay.it/itm/301725416168?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

And now I have this little leak of oil:

Anybody found a thermal compound paste that seal ferrofluid effectively?

 

[fechter]

Silicone RTV works well. It glues the side cover on but it can be pried off using a blade or thin screwdriver as a wedge.

 

[spinningmagnets]

Posted on Facebook ES by Sketch Coleman.

Yesterday was in the mid 90's and while riding in the late AM my mxus 3t v2 3k motor was in the high 70°c instead of the low to mid 60°c I'd previously seen (ferrofluid is installed and high regen always active.)
Installed my 2nd hubsink set on it, (heat was brutal to work in,) turned up my amps to max as per instructions and went to try and deliberately overheat it. Well, I bombed about everywhere for nearly an hour at top speed and acceleration and eventually got it up over 100°c and was trying to push higher but at every light it kept dumping the heat out about as fast as I raised it accelerating smile emoticon Stopped for a Cig at the beach and in 5 min it scrubbed so much heat it freaked me out a lil. With dedication to the task wink emoticon I eventually got it up above 110°c but unfortunately as soon as it hit 115°c the CAv3 starting limiting current (I don't think I ever changed the settings?) so my experiment was over.
After I came back in, I inspected the ring and noticed a fair amount of thermal paste had been squeezed out the sides (heat expansion perhaps?) The centrifugal force caused wave patterns as well as creeping up the side of the hubsink (how best to safely clean that up?)... But what an incredible thrillride, although in retrospect the speed was a touch dangerous.

 

[sketchism]

Posted on Facebook ES by Sketch Coleman.

Yesterday was in the mid 90's and while riding in the late AM my mxus 3t v2 3k motor was in the high 70°c instead of the low to mid 60°c I'd previously seen (ferrofluid is installed and high regen always active.)
Installed my 2nd hubsink set on it, (heat was brutal to work in,) turned up my amps to max as per instructions and went to try and deliberately overheat it. Well, I bombed about everywhere for nearly an hour at top speed and acceleration and eventually got it up over 100°c and was trying to push higher but at every light it kept dumping the heat out about as fast as I raised it accelerating smile emoticon Stopped for a Cig at the beach and in 5 min it scrubbed so much heat it freaked me out a lil. With dedication to the task wink emoticon I eventually got it up above 110°c but unfortunately as soon as it hit 115°c the CAv3 starting limiting current (I don't think I ever changed the settings?) so my experiment was over.
After I came back in, I inspected the ring and noticed a fair amount of thermal paste had been squeezed out the sides (heat expansion perhaps?) The centrifugal force caused wave patterns as well as creeping up the side of the hubsink (how best to safely clean that up?)... But what an incredible thrillride, although in retrospect the speed was a touch dangerous.

that wasn't actually me who posted it but i love it and the setup! haha

 

[Offroader]

Installed 2nd set, does that me he used two hub sinks together on one motor side by side?

Going away for a couple of weeks but when I get back I'm going to start my own testing on this Ferro Fluid and give my feedback here. Going to be testing in a Cromotor V3 of which I have two identical motors. If this stuff works I'll convert over to it.

When I read that post and hear "Cycle Analyst", I think of no OVS or overdrive which is what really heats up the motor. Without Overdrive and using a Max-E, my top speed on my bike would be limited to 36 MPH, but I push my bike to 55 MPH with OVS and my MAX-E and that is when I really notice the heat. To give more information, without OVS my peak watts would be limited to about maybe 2500 or less at top speed, but with OVS I'm pushing 7600 watts and it stays at those high watts.

Not bashing but just trying to keep things honest, kind of tired of reading people's posts without taking stuff like this into account. I don't think I could overheat even just a vented motor without OVS. I remember running my sealed cromotor with no cooling in the summer here in NYC without overdrive and it was very difficult to overheat the motor if staying on the street. The only way to overheat it was to go off-road.

The other thing that was left out is how many watts is he even pushing?

Granted, FF + hubsinks is probably far better than a sealed motor.

Will be doing my own testing and comparing it to active fan cooling which I know keeps my motor cooled off at 7600 peak watts at 95F summer weather, and that is with using a Max-E and overdrive, which gives me an extra 20MPH of speed on the street and overheats the crap out of a motor.

Will start testing this beginning of July.

Maybe FF + hubsinks works, but you will all finally get an honest answer from someone who already has one of the best cooling solutions out there to compare it against.

The biggest test for FF + hubsinks will be if I have to stop my bike at any time for a cooldown, I currently never have to do this with my fan setup, I drive as hard as I want and the only times I get super heated are huge steep dirt hill climbs but I can full throttle it after the climb without stopping.

I do have to turn up the fan speed on hotter days because of the extra heat. If I'm having to do cooldown stops with FF + hubsinks, then it is a fail for me.

 

[bigbore]

To give more information, without OVS my peak watts would be limited to about maybe 2500 or less at top speed, but with OVS I'm pushing 7600 watts and it stays at those high watts.

Not bashing but just trying to keep things honest, kind of tired of reading people's posts without taking stuff like this into account. I don't think I could overheat even just a vented motor without OVS. I remember running my sealed cromotor with no cooling in the summer here in NYC without overdrive and it was very difficult to overheat the motor if staying on the street. The only way to overheat it was to go off-road.

I've been using Ferrofluid from a year now and already bought a set of Hubsinks but not installed yet because before installing I want to be sure that they are really useful for my setup and my way of riding.
I have a QS205 30X4T V3 with 10ml of FF laced to a 19" MC RIM with a 70/100-19 motocross tyre and a Max-e with a 20S14P made of LG HE2 cells. I have a battery current limit at 140A and phase at 405A.
Did you try to stay with OVS at 0 and increase Power Timing?
With my setup I can reach 100Km/h of top speed in the same way increasing OVS or Power Timing but at that speed I have no more power drop and that stress the motor and the battery so I prefer to stay a little lower with my settings as described here: https://endless-sphere.com/forums/viewtopic.php?f=30&t=87712#p1285153

With my current settings (Power Timing = 1,04 and OVS = 0) for the moment the only way I found to reach the motor T limit is riding in deep sand and also climbing off road steep hills do not pass the motor temp of 80°C and on flat road I rode many times at 90Km/h for 4Km with a motor temp maxed at 75°C

Edit: as Rix said I forgot to mention the rear wheel

 

[Rix]

I don't think I could overheat even just a vented motor without OVS. I remember running my sealed cromotor with no cooling in the summer here in NYC without overdrive and it was very difficult to overheat the motor if staying on the street.

In the spirit of keeping things as accurate and honest as possible, don't forget, your 3.00-17 SR241 has an OD of 23.7 inches, vs the 25-27" wheels some of the other folks are running. That in itself makes your set up harder to over heat vs someone running a 26MTB rear for a 19MC rear. That whole mechanical advantage thing. And this brings me to my next point, even though I look forward to your real world findings after you get back from what ever it is your doing, your data is going to be different than say Grande Allesagio (Big Bore) and others. That said, as you and some other know, I have ran 26MTB wheels, 24MTB wheels, 17, 18, and 19MC wheels. Based on the stuff I ride and where I live, I am going back to the 17" wheel on the rear and running either a 24TMB up front or a 19MC up front. As far as the front goes, I have both rims laced to 20mm DH hubs so its not much trouble for me to swap back and forth there. I know it looks a little funny, but the 17 MC rim running a nice trial tires in the 2.75-3.25 inch wide range is the best set up, performance wise. And this brings me to my next point. I have ran all sorts of hub motors on builds over the years, 5403, 5404, 5405, MXUS 3k, TC4080, TC3080, H4080, H3540 and even a MAC10 motor. Even though I am not a very tech savvy guy, I have a little experience with a limited variety of hubmotors. Of all these motors I have ran, the power to weight to peak current ratio, the H4080 IMHO is king. I want to clarify the H4080 isn't the best motor out there for peak current, but for its OA weight, its the best in my opinion. My only bitch was the H4080 needs an aluminum stater armature and a 10MM X 14MM axle. I heard these mods are now standard, but haven't confirmed yet. If this is the case, the H4080 with a 17MC rim and tire with FF and Sketch's cooling fins is going to be my next endeavor for a high powered lightweight set up.

 

[John Bozi]

and dont forget the turn counts

ducks for cover

 

[Offroader]

Yeah all those factors do matter.

You know what is funny Justin named this thread the "definitive tests" where he had more strict standards of measuring the performance of cooling. I know he mentioned a few times that he wanted certain methods for testing cooling. The problem was is that the way justin wanted you to measure the cooling was kind of complicated where you would need to run the motor for hours to get a steady state temp.

You really do need better ways to test and compare because everyone is riding differently, using different wheel sizes, different turns, ambient temps.

My test is simple, I need the best cooling possible because of the way I ride and the power I am pushing. I use my bike like it was a dirt bike so I generate so much heat.

My test will basically see if FF + hubsink can compare to a hubmotor which has been sealed inside to direct cool air in and hot air exhausted out at a very high flow rate. Basically, I have the best forced air cooling can offer and it will be a test if FF + hubsinks can at least match the performance.

My prediction is that it will not come close because when I put my hand near the exhaust side of my motor the air is so hot it will burn my hand and all that hot air is being blown right out of the motor. Not sure if some fins can throw that amount of heat off. We shall finally see and if it does I will say I was wrong and FF + hubsinks are the way to go.

 

[Cowardlyduck]

I want to clarify the H4080 isn't the best motor out there for peak current, but for its OA weight, its the best in my opinion. My only bitch was the H4080 needs an aluminum stater armature and a 10MM X 14MM axle. I heard these mods are now standard, but haven't confirmed yet. If this is the case, the H4080 with a 17MC rim and tire with FF and Sketch's cooling fins is going to be my next endeavor for a high powered lightweight set up.

Don't forget the Leaf Motor...or even better the new Edge Motor since it has the Aluminium stator. While they both only have 35mm wide magnets, they both use 0.35mm laminations which makes them more efficient and have much lower cogging making them approximately on par in terms of power capability to the HS4080.
My Leaf motor weighs in at just 7.2KG which is noticeably lighter than my HS4080 by over 1KG, but I can push it at the same ~5KW without issue. Yes it will not give quite as much torque for the same watts due to the 5mm less magnet height, but IMO that is more than made up for by it's lower weight and higher efficiency.

Anyway, just wanted to add that, as I think that any DD motor still using 0.5mm laminations, like the HS40xx motors, should no longer be a contender for the ultimate high power light weight setup.

Cheers

 

[spinningmagnets]

when I put my hand near the exhaust side of my motor the air is so hot it will burn my hand

It will....*cook my kielbasa (*visualizes an aluminum box alongside hub, with a mini cast-iron grill inside)

I think that any DD motor still using 0.5mm laminations, like the HS40xx motors, should no longer be a contender for the ultimate high power light weight setup

I completely agree. Good heat-shedding is awesome, but...it's always better to make less waste-heat in the first place.

The Ferro-Fluid came completely out of left field, but....hubsink fins, ventilation with interior water-proofing, thinner laminations...all could have been an option straight outta China five years ago.

 

[Rix]

I want to clarify the H4080 isn't the best motor out there for peak current, but for its OA weight, its the best in my opinion. My only bitch was the H4080 needs an aluminum stater armature and a 10MM X 14MM axle. I heard these mods are now standard, but haven't confirmed yet. If this is the case, the H4080 with a 17MC rim and tire with FF and Sketch's cooling fins is going to be my next endeavor for a high powered lightweight set up.

Don't forget the Leaf Motor...or even better the new Edge Motor since it has the Aluminium stator. While they both only have 35mm wide magnets, they both use 0.35mm laminations which makes them more efficient and have much lower cogging making them approximately on par in terms of power capability to the HS4080.
My Leaf motor weighs in at just 7.2KG which is noticeably lighter than my HS4080 by over 1KG, but I can push it at the same ~5KW without issue. Yes it will not give quite as much torque for the same watts due to the 5mm less magnet height, but IMO that is more than made up for by it's lower weight and higher efficiency.

Anyway, just wanted to add that, as I think that any DD motor still using 0.5mm laminations, like the HS40xx motors, should no longer be a contender for the ultimate high power light weight setup.

Cheers

Good point CD, the reason I didn't mention the Leaf is because I don't have any experience with it.......yet. H40xx series is rumored to be going through some updates as I mentioned previously, may it will get lighter in the process, if I can verify it.

 

[John Bozi]

I've been torturing my 1kw motor. I've been running about 7kw through it in 10 minute 4km bursts to the shops and back. It's the hottest it's ever been. I don't think I have enjoyed the feeling of a bike this much. So light with only 24s 5ah lol.

I used to say it saturates at about 4kw and it does but there is still a bit more grunt and growl at low speeds but at the top end its clearly better...

if it were summer and no ff or hubsinks, it would be finished by now.

IF she dies as I guess I will over do it with no temp sensor...
Too many bikes and parts to care about this motor and bike...

 

[macribs]

Hi there John. I am a little lost I must say. What motor are you referring to in your post? And what controller/amp setting do you run?