DasDouble
100 kW
Has anyone tested yet if a fan mounted on the swingarm, pointing at the hubsinks is accellerating the cooling-down process decisive?
Definitive Tests on the Heating and Cooling of Hub Motors
- Thread starter justin_le
- Start date
SlowCo
1 MW
DasDouble said:
Yes, look at the post from Jestronix a little further down this page:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=48753&start=1925
DasDouble
100 kW
SlowCo said:
Ah that seems to do a big job. Im gonna have to give this a try. Thanks SlowCo.
hillzofvalp
100 kW
Very good work guys. I have an esk8 motor I call Trillium.. it has sort of dragged on. Perfectionism kills. I'll be sending it to Justin for review... has 6063 rotor and has been extruded.
fechter said:
Hey Fechter, it's worth pointing out here that we can answer this quite precisely with the data I've presented rather than doing just a "try and see". I've been going through some pains trying to present all these graphs with numeric axis not just because they look pretty, but to give people the raw info needed to make educated decisions based on the results.
Your line of thought here is a perfect example where we can get a good answer without any testing at all using the info that I published. Referring to this graph here (from https://endless-sphere.com/forums/viewtopic.php?p=1368908#p1368908)
You can see that at 5-6 mph, say 9kph, the shell to ambient conductivity is about 5.5 W/degree without hubsinks, and about 8 W/degree with hubsinks. To achieve that same 8 W/degree conductivity without the hubsinks you need a passing aiflow of 18 kph. So if your side fans end up blowing air on the side cover roughly equivalent to a 18kph headwind, then the cooling will be exactly as having no fan but hubsinks installed.
Say your fans blow at more like 30 kph, then the effective conductivity is 12 W/degree. But to determine the total effect, you need to also factor in the core to shell conductivity levels.
From this graph here:
You can see that that the core to shell conductivity with Statorade in this hub is 4.5 W/degree at your 5-6 mph point.
That results in NET conductivities (Knet = 1/(1/K1 + 1/K2)) as follows
5-6 mph, No Hubsinks = 2.48 W/degree
5-6 mph, With Hubsinks = 2.88 W/degree
5-6 mph, with 18kph fan = 2.88 W/degree
5-6 mph, with 30 kph fan = 3.27 W/degree
So it helps a bit, no doubt, but you will get diminishing returns as you put more and more effort into cooling the shell. Even if you had absolutely perfect thermal conductivity from the shell to ambient, you're still limited by the 4.5 W/degree from the core.
Tolkano
100 W
Whats the deal when it comes to applying statorade and varnish on the magnets?
Do you use statorade first then spray varnish over it or vice versa? Or does it not matter
Do you use statorade first then spray varnish over it or vice versa? Or does it not matter
Do you know of a varnish that sticks to liquids?
Tolkano
100 W
amberwolf said:
Don't liquids dry at a certain point?
SlowCo
1 MW
tolkaNo said:
Google "ferrofluid" (=statorade) or look it up on YouTube. Then try to understand if it would work with varnish covering it.
Tolkano
100 W
SlowCo said:
It's only supposed to go in between the gaps of the magnets no? The varnish will still cover the other 99% of the magnets because that's not where the fluid is supposed to go was my understanding
Im just asking the question if no-one has the answer its fine :?
SlowCo
1 MW
tolkaNo said:
Short answer: if you vent the side covers then first put on the varnish (and let it dry) then add ferrofluid.
If you don't vent the side covers then don't put varnish on the internals of the hub motor as it will act as an heat insulator lowering the effect of the ferrofluid. And be aware that you need Statorade or equivalent ferrofluid that can handle the heat and doesn't dissolve the varnish and the glue of the magnets.
The ferrofluid "bridges" the gap between the stator and the rotor to transfer heat from the stator to the rotor. Ferrofluid acts in a special way around magnets forming spikes that can form that "bridge". So it has to stay fluid to do that. Read more here:
http://www.ebikes.ca/product-info/statorade.html
Tolkano
100 W
SlowCo said:
I feel like its easier to just not varnish the magnets at all if using ferrofluid then
spinningmagnets
100 TW
Most builders who have used a water-proofing motor-varnish have done it to rust-proof the insides when they decided to add vent-holes to the sideplates, which is usually done to let out heat.
Statorade also helps the motor shed heat, but...a small percentage of particles in the dust around everyone is ferrous, so if you had vent holes combined with statorade, there is a fear that ferrous dust-grit would accumulate in the statorade. I don't know of anyone who has added motor varnish to a sealed motor and then added Statorade. If you try this, you would likely be the first to do so.
The fluid in Statorade is oil-based, using an oil with a low vapor-pressure, so...any evaporation would take many years, if at all.
Statorade also helps the motor shed heat, but...a small percentage of particles in the dust around everyone is ferrous, so if you had vent holes combined with statorade, there is a fear that ferrous dust-grit would accumulate in the statorade. I don't know of anyone who has added motor varnish to a sealed motor and then added Statorade. If you try this, you would likely be the first to do so.
The fluid in Statorade is oil-based, using an oil with a low vapor-pressure, so...any evaporation would take many years, if at all.
I actually did this back in June 2016, and I am continuing to experiment doing so.spinningmagnets said:
This was the result of my initial attempts:
https://endless-sphere.com/forums/viewtopic.php?f=30&t=56965&start=400#p1198704
I did the same thing on another motor with smaller vent holes and the result that time were much better:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=48753&start=1700#p1267918
Doc had some good thoughts on what caused this difference also:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=48753&start=1725#p1279216
As mentioned in the posts above, my other motor is a Leaf '1500w' I have also vented with FF and heat-sinks. It doesn't seem to be suffering as much as the HS4080 did and I have been continuing to run it with FF, venting and Fans for about another 1000km or so now. So far it still seems to be running fine, so I have no reason to open it back up again as it is a PITA, but when I eventually do, I will try and share the results then.
I also have a '1000W Golden motor' which is just vented on one side and has about 5ml of FF. I've not opened it at all since adding the FF and it's done at least 3000km. So far no issues apart from a bit of increased drag when hot.
***EDIT***
Sorry Spinning Magnets, just realised you specified "Sealed" motor....which I even quoted. :lol: I'm sure my experiments are still somewhat relevant however so I'll leave the response as is.
Cheers
DasDouble
100 kW
Allex said:Meanwhile in Russia, they take another way to cool down the motors.
It seems that ferrofluid is not enough for them so they actually use Active cooling and it is far more complex one.
Has anyone an idea how I can get my hands on these 3D files? I would like to do that for my QS 205 V3 as well. That would save a lot of time, having these as a template. Thanks
Allex
100 MW
https://www.youtube.com/watch?v=PpkxWSEWJy0&t=92s
This guys currently builds a setup for a V3
Ask him.
This guys currently builds a setup for a V3
Ask him.
justin_le said:
For those following this longevity test, I did several more weeks of this experiment approaching nearly 2 months now, with 9mL of Statorade in a MXUS motor running at 120 oC. Dark blue line is the measured thermal conductivity, light blue is the conductivity reference with no Statorade.
I'd say that's pretty darn flat. A slight decline perhaps but still a long way from the current 4.8 W/degree down to 2.6 W/degree. Total equivalent distance is over 65,000 km now. That's one and a half loops around the planet.
The experiment has since been stopped since the anderson connector on the motor phase wires melted with the high field weakening current. With just 2 phase wires connected the sensorless controller went a bit berserk and the motor shook itself from the test stand and dislodged the IR sensors and all that. I've needed to use the wind tunnel for other things so I didn't bother setting it back up and am not sure if there is much value in continuing this.
liveforphysics
100 TW
The samples with FF that gummed up were perhaps due to varnish/epoxy internal coatings dissolving.
Do we have any examples of it getting gummy over time in motors that are only using stock surface coatings (like I assume your test used?)
Do we have any examples of it getting gummy over time in motors that are only using stock surface coatings (like I assume your test used?)
Nice work Justin!
Yeah I can't disprove what Luke said above and it is entirely possible it was down to the coatings I applied in my cases that caused the FF to be consumed over time. I ended up just adding more to one of those motors so it will be interesting to see how that turns out. :lol:
Cheers
Yeah I can't disprove what Luke said above and it is entirely possible it was down to the coatings I applied in my cases that caused the FF to be consumed over time. I ended up just adding more to one of those motors so it will be interesting to see how that turns out. :lol:
Cheers
eCue
10 kW
Percentages wise its a 85% improvement in heat shedding 
mrbill
10 kW
Hi Folks:
I've got a partial syringe of Type A Statorade purchased in 2016 or earlier and a full syringe I purchased in March 2018 labeled as "Statorade". Can anyone tell me if these formulations are compatible and can be mixed together in the same motor?
Thanks.
I've got a partial syringe of Type A Statorade purchased in 2016 or earlier and a full syringe I purchased in March 2018 labeled as "Statorade". Can anyone tell me if these formulations are compatible and can be mixed together in the same motor?
Thanks.
DasDouble
100 kW
Has someone already tried Sprayon together with 8ml ff?
macribs
10 MW
- Joined
- Jul 22, 2014
- Messages
- 3,702
Don't know if it was SPRAY ON varnish but there was one report of red varnish that did not work well with statorade. If no one has actually tested that brand I would just skip it to be on the safe side. After all when using statorade your hub will get a thin layer of oil coating inside that might be enough to avoid rust and corrosion? Or if you do have the motor apart rub som gun oil or similar over steel parts inside motor.
I just wanted to give an update about my 40mm EDF fan in my MXUS 3000 Turbo hub motor. The motor is ducted using silicone to direct outside air through the coils. The side cover of my hub motor has holes drilled into it.
I can say that I've ran it the whole last summer, and am running it this summer without any issues. When the weather is hot outside and around 90F degrees, this is the time I like most to ride my bike and also the most difficult times to deal with motor cooling, I am pushing the MXUS motor hard at 8000KW for a very long time with my large 3 KWH battery. I ride extremely hard with only using full throttle.
The silicone ducting I made directly on the coils and aluminum stator has held up without any issues.
I can adjust the speed of the EDF fan and with the very hot summer days I need to turn it up to 80 watts (this is what the 12 volt power supply draws as read on my Max-E) to be able to drive my bike as hard as I can with any risk of overheating. The great thing is I run this 40mm EDF at these high speeds for my entire 1-2 hour bike rides without any issues. This tiny EDF is very reliable and very powerful also at moving air. When this tiny EDF is using 80 watts it is spinning extremely fast, if you held the fan at arms length away it would feel like sticking your head out of a car window driving on the highway. No computer fan would even come close, these fans are used to fly airplanes at very high speeds.
The noise isn't too bad but it isn't silent. At a speed above 15MPH you won't hear it over the wind noise. You do get used to the noise, just like you would the noise of your car, you just don't notice it. The great thing is I can adjust it by reaching back under my seat, so if I want it silent I just turn the knob and I can do this while riding also.
I'm going to finish my Cromotor wheel build to compare this to FF and hubsinks soon. I want to do a direct comparison to see if its worthwhile to do this kind of fan cooling when a more simpler solution is available.
Here is a link to the 40mm EDF I use:
https://hobbyking.com/en_us/dr-mad-thrust-40mm-8-blade-alloy-edf-8000kv-motor-330-watt-3s.html
I can say that I've ran it the whole last summer, and am running it this summer without any issues. When the weather is hot outside and around 90F degrees, this is the time I like most to ride my bike and also the most difficult times to deal with motor cooling, I am pushing the MXUS motor hard at 8000KW for a very long time with my large 3 KWH battery. I ride extremely hard with only using full throttle.
The silicone ducting I made directly on the coils and aluminum stator has held up without any issues.
I can adjust the speed of the EDF fan and with the very hot summer days I need to turn it up to 80 watts (this is what the 12 volt power supply draws as read on my Max-E) to be able to drive my bike as hard as I can with any risk of overheating. The great thing is I run this 40mm EDF at these high speeds for my entire 1-2 hour bike rides without any issues. This tiny EDF is very reliable and very powerful also at moving air. When this tiny EDF is using 80 watts it is spinning extremely fast, if you held the fan at arms length away it would feel like sticking your head out of a car window driving on the highway. No computer fan would even come close, these fans are used to fly airplanes at very high speeds.
The noise isn't too bad but it isn't silent. At a speed above 15MPH you won't hear it over the wind noise. You do get used to the noise, just like you would the noise of your car, you just don't notice it. The great thing is I can adjust it by reaching back under my seat, so if I want it silent I just turn the knob and I can do this while riding also.
I'm going to finish my Cromotor wheel build to compare this to FF and hubsinks soon. I want to do a direct comparison to see if its worthwhile to do this kind of fan cooling when a more simpler solution is available.
Here is a link to the 40mm EDF I use:
https://hobbyking.com/en_us/dr-mad-thrust-40mm-8-blade-alloy-edf-8000kv-motor-330-watt-3s.html
eCue
10 kW
Excellent mod and fan wow. Hub Motor cooling is going to be revolutionized by the looks of it. Looking forward to tests.Off hand Im curious if the added heatsinks slows cooling or increases it. The gap on the rc fan compared to current methods would be most interesting as well
from link - This 40mm, 8-blade combo with the inrunner motor was developed by Dr. Bret Becker, for his record breaking Electrolyte Micro EDF sport jet, and is capable of pushing the model past the 100mph barrier
from link - This 40mm, 8-blade combo with the inrunner motor was developed by Dr. Bret Becker, for his record breaking Electrolyte Micro EDF sport jet, and is capable of pushing the model past the 100mph barrier
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