Definitive Tests on the Heating and Cooling of Hub Motors

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rumme
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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by rumme » Oct 14, 2017 12:11 pm

Rix wrote:
I never liked the idea of adding external small fans , because it just adds another electrical element that can get damaged.
Can you elaborate, I am not understanding what you mean with adding "another electrical element that can get damaged". Seems to me the fins, whether they got damaged or not, wouldn't affect the functionality of the motor.
Ive seen some people mount 1 or more electrical small cooling fans to the hub motor. Id rather use cooling holes to let the trapped hot air escape or air scoops fastened to the hub that deliver the moving air right over the hub motor or of course heat sink fins.

I'm currently running a 3k nominal hub motor, but it has been treated with ferro fluid and I can run it at 5000 watts, and it gets very warm, but not hot. I cut my phase wires to be as short as possible to the controller/ motor and upgraded from 10 gauge wire to 8 gauge wire. I think if I wanted to run the motor at 6000- 7000 watts, it could take it, but I would need to add either heat sink fins to the motor, or a air scoop to force the moving air over the hub. Ive tried cooling with auto trans fluid and did not like the results. I still think air cooling holes in the side covers is the best and easiest way for cooling, but I ride on many gravel roads and it is to dusty. I don't wanna risk getting the inside of the hub motor dirty.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by madin88 » Oct 14, 2017 12:24 pm

csc wrote: Madin 88 : ok thanks ! I stayed in 72v (so 84.2 full) and kept a 26 wheel size (though front is a moto 21", it's the same diameter).

Question : will a 3 t 75v 133A and a 4t 100v 100A perform the same when going uphill in terms of heat ?
yes exactly, but the 4T has a little bit higher copper fill (it is 4x16 vs 3x20 strands) so it is a bit more efficient.
btw: have you thought about using smaller wheels? doing so would lower your torque requirement (= heat) a lot.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by csc » Oct 14, 2017 1:04 pm

Yep. That's gonna happen to the rear wheel soon if I can't lower the temps : probably a rear 5k in 19". I'll keep the 21" front trail wheel for occasionnal single track reasons.

The question is what winding for the rear 5k. Being more powerful, a 5k 3t might be able to climb without overwarming... or not.

Any opinion about that is welcome. Knowing that I have to find a config that would still go uphill easily with a 180 kilos payload (2 people + a trailer) and that I'll keep a 3k in the front wheel, so the overall eficiency would be specific to this 2wd config.

Just as a reminder of this thread's title : 2wd is a very very very good way to avoid heat !!!! (as soon as the fork can really stand it... and the windings have been wisely chosen)

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by wturber » Oct 14, 2017 2:13 pm

Has anybody tried adding little scoops to cooling holes? They could be as simple as a half sphere cut in half and press fit into the cut out hole. They would face forward when at the top of the wheel rotation and backward when at the bottom. You might even get really creative and use fewer but larger scoops attached to the spokes near the rim. These scoops would feed air into ducts that connect to holes cut into the motor side covers. In either case, you would probably want to have some holes cut into the covers that do not have any scoops attached as way for the incoming air to escape.
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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by rumme » Oct 14, 2017 2:46 pm

wturber wrote:Has anybody tried adding little scoops to cooling holes? They could be as simple as a half sphere cut in half and press fit into the cut out hole. They would face forward when at the top of the wheel rotation and backward when at the bottom. You might even get really creative and use fewer but larger scoops attached to the spokes near the rim. These scoops would feed air into ducts that connect to holes cut into the motor side covers. In either case, you would probably want to have some holes cut into the covers that do not have any scoops attached as way for the incoming air to escape.
yep..did it several years ago....used clear silicone to attach the plast scoops to the sides of the hub motor, to direct the moving air into the hub motor. works great.

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Definite happiness with Cooling of Hub Motors

Post by John Bozi » Oct 14, 2017 2:49 pm

Image

Good to see people are still searching for the ultimate cooling methods. I have nothing to ask questions about how to solve this problem or that problem.

I would imagine there are many out there that are also active in similar ways and then have nothing much to say anymore.

I have a 50 kg Q76 24ah @24s lipo with an old school thin lyen 18 fet to QS 205 8t 17" mc tyre FF (statorade) hubsinks under 8.5 kw spikes 65kmh hot off but usually rolls out to about 55kmh up hill.

On Road never overheats.

Off Road I have to climb some serious mountains @ constant 6+ kw to overheat. Then I have beer in my backpack and enjoy the scenery. One stop on a 40km ride is a good thing!

No need for 2wd weight increase or mid drive complexity and fails. Or cleaning out the filth that comes with an open motor. I got tons of traction with the 3.25" moto tyre.

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Thank you to the community for getting me to here,
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especially Sketch and Justin, and thought I would do a final share because I have nothing much else to say.

Now all I do is ride with an occasional beer stop.

JB

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by rumme » Oct 14, 2017 3:10 pm

John Bozi, nice ebike....

I can run around 5000 watt regularly and my motor and controller get very warm, but not hot { I could hold my hand on them and it wont burn me} .

If I go to the 6k and above zones, then things start to get hot , but I don't generally push the power to those levels.

I noticed you mounted your controller in the most common spot, upfront. I chose to go a different route for my ebike, for a few reasons.

I mounted it below my seatpost and up a bit higher from the ground. I used my plasma cutter to cut a square cutout in my frame, so the controller can slide in and this allows air to circulate around the whole controller { unlike the front mounting method where the whole rear of the controller is mounted against the frame, so no air can circulate around it. }

It also keeps the controller cleaner/ dryer and it brings the controller closer to the motor, so the phase wires can be shorter.
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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by csc » Oct 14, 2017 3:32 pm

Message received, John Bozi ! I feel that you talk truth when I see your 50 kilos 8t config. Especially when you explain your beer motor cooling method.

My only limit with your advice is that I need a cargo thing that can replace a car often + cross over all kinds of landscapes occasionnaly + 80 km range with a 100 kmh top speed in order to go to work, as I now live far from it.

Resulting in a very heavy machine, which one only bike hub engine can't push.

#countryside

In fact as long as you don't need that much range, speed and cargo power, your config is ideal IMO. Managing the motors temps in my config is not easy, sorry for the "already solved" aspect of my questions. I could sum up like this : is it better to lower the motor speed (8t rather tran 3t) + increase field weakening OR fast winding without field weakening ?

My feeling is that FF and hubsinks helped a lot but not as much as choosing the good winding for this 2wd cargo program. Back to slower engines soon, at your request !
Last edited by csc on Oct 14, 2017 5:35 pm, edited 2 times in total.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by Cowardlyduck » Oct 14, 2017 5:30 pm

I'll just leave these here....again:
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All I'll say is I won't be bothering with this kind of setup again now that FF + Hubsinks is an option. When I started down this road of fan cooling it wasn't. That being said, my latest setup is still going strong over 6 months later keeping my poorly tuned Leaf motor/Adaptto Mini-E combo cool enough. Hit 9.1KW peak the other day. :shock: Usually it's only around 3KW cont though.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by csc » Oct 14, 2017 5:50 pm

Thanks Cowardlydyduck, I've read your messages with interest. No doubt fans are a very efficient way to dissipate heat.

My questionning these days, though, is how to have a minimum of heat to remove at 14kw nominal / 25 KW peak, by not producing it.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by Samd » Oct 15, 2017 1:28 am

csc wrote:Thanks Cowardlydyduck, I've read your messages with interest. No doubt fans are a very efficient way to dissipate heat.

My questionning these days, though, is how to have a minimum of heat to remove at 14kw nominal / 25 KW peak, by not producing it.
This is vital.

Find a motor with a decent portion of the rpm band having efficiency over 80%.

Or use a transmission to exploit the main rpm / efficiency portion.


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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by litespeed » Oct 15, 2017 8:29 am

csc wrote:Litespeed : 102 kmh at OVS 0 but... ind timing 590 us and angle corr -11°. I'll be testing this afternoon a frankly lower ind + frankly bigger ovs, just to see what happens.

What are your Ind timing and angle corr values with the 3.5t ? To the others : sorry for not being in the adaptto thread but I would'nt like to miss the answer?
Here you go.

Hope you get it figured out....if it were me I would record all the settings, jack the bike up and try tuning it again Dr. Bass style just to be sure all is the best it can be.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by csc » Oct 15, 2017 1:55 pm

Thanks Litespeed ! I'll answer on the adaptto thread as this is quite not the good one for these questions

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by Rix » Oct 16, 2017 11:03 am

wturber wrote:Has anybody tried adding little scoops to cooling holes? They could be as simple as a half sphere cut in half and press fit into the cut out hole. They would face forward when at the top of the wheel rotation and backward when at the bottom. You might even get really creative and use fewer but larger scoops attached to the spokes near the rim. These scoops would feed air into ducts that connect to holes cut into the motor side covers. In either case, you would probably want to have some holes cut into the covers that do not have any scoops attached as way for the incoming air to escape.
Pendragon8000 built an "Air Impeller" that mounted between the disk brake and the hub. It directed air into the vent holes. It was made out of either delron or a nylon type plastic. He sent me one for testing and I found that it did work better than just vent holes. I based this on a hill climb I had done lots of times and how hot my hubmotor was to the touch. Not scientific at all. Anyway I took it off and tried to modify the impeller and ruined it. At one point, Pendragon8000 (Ken) was going to make these and sell them after he got his shop up and running. I don't know what happened.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by speedmd » Oct 18, 2017 8:40 am

Not sure if posted previously on es, the way siemens cools the new e plane motor.

http://www.siemens.com/innovation/en/ho ... red-flight

https://www.siemens.com/innovation/en/h ... light.html

They use non conducting liquid to pull copper losses out. Interesting read.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by Rix » Oct 18, 2017 12:41 pm

Hit 9.1KW peak the other day
Thats alot for a 6Fet controller. Was this with 18s?

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by Cowardlyduck » Oct 18, 2017 4:28 pm

Rix wrote:Thats alot for a 6Fet controller. Was this with 18s?
Yes, so about 125amps from the battery. Mind you it was only very brief and the controller went into thermal protection very soon afterwards.

I won't be doing it again though...it really does risk blowing something...I blew my last Mini-E at 8.4KW...don't wanna repeat that again.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by Rix » Oct 18, 2017 9:29 pm

Yes, so about 125amps from the battery. Mind you it was only very brief and the controller went into thermal protection very soon afterwards.

I won't be doing it again though...it really does risk blowing something...I blew my last Mini-E at 8.4KW...don't wanna repeat that again.
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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by Ohbse » Oct 19, 2017 1:35 am

I ran my mini-e at 7.5kw for well over a year of daily riding, that was certainly about the limit for reliability however. My QS 205 3.5T killed it as it's a bit harder to drive and I was already right on the limit. The Adapttos are very difficult to establish correct timing on however, many people experience greatly increased heat as things aren't quite timed right.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by Cowardlyduck » Oct 19, 2017 2:11 am

Ohbse wrote:I ran my mini-e at 7.5kw for well over a year of daily riding, that was certainly about the limit for reliability however. My QS 205 3.5T killed it as it's a bit harder to drive and I was already right on the limit. The Adapttos are very difficult to establish correct timing on however, many people experience greatly increased heat as things aren't quite timed right.
Yeah, that's exactly right and what I would say also for the Mini-E. My first one died at 8.4KW driving a HS4080.
I would say it's limits are 8KW for a 5T, 7.5KW for a 4T, 7KW for a 3.5T, and 6.5KW for a 3T motor....although it would vary between each unit as they are not all identical. That's why I only bought a Midi-E for my Alpha I plan to run at 10KW...anyway, this is not the thread for this discussion, so I'll leave it there.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by Jestronix » Oct 19, 2017 2:53 am

I run a 3k mxus with hubsinks and trans oil. it gets me most places. The long up hill rides in the 3 to 6kw cause me at least one or two scenery stops. Im actually looking at installing heatsinks on the side of the hub, i have some low profile ex chipset sinks that im going to look at. However Im wondering how much heat are the side covers actually producing and will it make any difference? in theory oil washing up over the sidecovers should be enough to make heatsinks worth it. Im also looking at running a smaller diameter wheel, which always helps.

I have also had ideas of running some serious CFM fans attached to the singarms pointing in from bothsides onto the hubsinks. But complexity and things going into the fans is an issue. However if i manage to pull off a hub motor that doesnt overheat, ill be a happy man.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by macribs » Oct 29, 2017 4:53 pm

In fact it's more and more obvious to me that if I want a heavy duty fast cargo thing, rear 3k is just too small. Trying to cool a motor is OK within reasonable limits : at some point removing heat doesn't solve the problem of it being generated. I think everybody here is OK with the idea that the more heat generated - no matter it's dissipated or not - the less eficiency. So when I read people with a qs 205 claiming they have a 20 kw bike, please don't mind if I have doubts !!! They have a 20 kw roller toaster, as I do now with my 3t config.

My conclusion is that I need a 3k 4t front in a 21" motorcycle rim with OVS 4 + a 5k turbo 4t in a 19" moto rim, OVS at 6. My 100% empiric approach tells me that it will be more efficient in real world use and not slower. Do you agree with that ?

Seems you get high temperatures even when you run 2wd. Yes your bike is heavy at 109 kilos. But the heat still seems high, too high.
I got a 205 now in a 17" and I get even more torque and less heat then when I tried it in 19" wheel. The bike is about 85 kilos or so, but I weigh in at 150 kilos. So it is really a lot of weight but a single qs 205 in 17" filled with plain of the shelf gas station motor oil I can ride WOT time and time again even uphill without overheating when I reduced wheel diameter.

Maybe the easiest solution for you would be to reduce the rim diameter and run 17" front and back? Or at least 18". Dial back on OVS as best you can do, and with FF and hubsinks you should be able to take your girl anywhere, keep all your journalist tools and still hit 100 km/h top speed without overheating. If you ride anything like I do, most of the time I am not in top speed, and that keeps motor working easy, and keeps temperature down. When you then need max speed, your motor is not close to temp limit already and should do fine.

If all else fails, you got the wrong motor to begin with. Get a bigger motor like 273, lace it in small as possible rim and you can enjoy a light weight front end without a heavy hub up front. Match that 273 with a punchy controller and you, your girl and your trailer should have all the torque needed to do serious riding.

Pro tip, flip those Adaptto controllers. Seems many are looking to get one, and no one are selling them. If you get the right parts you might even swap your overheating 2 wd setup for a rear 273 w/matching controller without spending much money.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by csc » Oct 30, 2017 2:37 am

Thanks for the advice Macrib

There's news about my heat issues. I worked a lot on the best way to setup my adapttos / 2x3t combo and found some pretty new to me conclusions, based on hall offset, angle corr and IND. I'll sum up in the adaptto thread.

BTW Litespeed, your over 600 ind might be out of range, unless you use a very slow/"high torque" (...) motor, according to my current thoughts. But if I remember correctly you use a 3.5t qs205. If there's an equivalence with MXUS in terms of behavior, you might check the adaptto threads in the few next days to see my results
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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by zzoing » Oct 30, 2017 3:49 am

If you take aluminium mesh with .7mm thick strands and you roll it into a kind of bandana arrangement, you can glue it with arctic adhesive around the outside of the motor and increase the heat dissipiation by 2x, it has the advantage that when you throw water on it will act as a sponge too. If you stick a roll of it to the hub at 45 degrees, all the strands at the base of the roll will be directly conducting heat away from the hub. it can multiply the hub surface area by 5 times for 20 dollars including 2x arctic thermal adhesive. it's made from aluminum oxide and boron nitride and rubbery glue.

I sometimes find myself wetting plants and moss in the forest at the top of a mountain to cool the motor down, aluminium mesh would be cooler.

here's a fast pic of the idea. perhaps can buy 100g nanotubes/graphene and anodize it straight into the hub :)
Image
Last edited by zzoing on Dec 10, 2017 3:19 pm, edited 1 time in total.

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Re: Definitive Tests on the Heating and Cooling of Hub Motor

Post by macribs » Oct 30, 2017 6:56 am

Plants and moss I like that. Use what you got to get where you need.

I am trying to picture what that alu bandana would look like, got a link to a pic?

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