I have found a way to easily and succesfully cool hub motors

[made_in_the_alps_legacy]

OK thanks for the clarifications, I will think twice about it then...

(the fins would act as a mesh for avoiding particles to drop inside the hub... and still leave the hub as a "relatively closed system" - but since I ride offroad too, it might be too much opening already)

last time I got my hub toasted was after 10kms (6.2miles) +1000m (3280ft) denivelation at about 3kW... without any cooling modifications... yet (I bought a throttle tamer instead ...)

 

[999zip999]

So where in the motor is heat generated ?
My guess is at just under or at the stator ring.
If so how to let the heat out at that point before transferring deeper or lock inside.

 

[cal3thousand]

This modification has resulted i me being able to push my 1000 watt motor, to 2500 watts and it only gets very warm..compared to it usually getting quite hot.

I appreciate your idea and I'm not shooting it down. But this particular claim that I quoted, doesn't really mean much. First, who said it was a 1000W motor? The motor manufacturer did and that is not standardized. Next, you don't tell us how long you can go 2500W and 'only gets very warm' is a very imprecise metric.

For example, a crystalyte HT3525 in stock format can do 2500W for 22 minutes before it 'overheats'. At 1000W, it will never 'overheat'.

The real question is whether your motor now has a higher capacity for heat shedding than previous.

BTW, what mystery motor are you working with? Any pics yet?

 

[macribs]

While we are waiting for pics of your cooling fins, would you be so kind to share what type of fins you used?
If you could put a link to the fins that would be great.

 

[ebikedelight]

This modification has resulted i me being able to push my 1000 watt motor, to 2500 watts and it only gets very warm..compared to it usually getting quite hot.

I appreciate your idea and I'm not shooting it down. But this particular claim that I quoted, doesn't really mean much. First, who said it was a 1000W motor? The motor manufacturer did and that is not standardized. Next, you don't tell us how long you can go 2500W and 'only gets very warm' is a very imprecise metric.

For example, a crystalyte HT3525 in stock format can do 2500W for 22 minutes before it 'overheats'. At 1000W, it will never 'overheat'.

The real question is whether your motor now has a higher capacity for heat shedding than previous.

BTW, what mystery motor are you working with? Any pics yet?

motor is a generic yescomusa 1000 watt D.D. rear hub motor off ebay for around $200 shipped with controller. Im not using stock controller , im using a Lyden which is pumping around 52 amps at 50 volts into the motor for certain sections of the trails I ride and hilly back roads that are made of gravel.

im not trying to convince anyone to do this mod...im just reporting that I came up with the idea, and am happy with the results. I personally would never try to run my motor at 2500 watts for 22 minutes , because I dont need that type of performance. I am comparing how hot my motor used to get, compared to how hot it now gets with the heat sink mods
running the same distance/ trails with similar throttle usage . My own experiments , although not 100 % precise, have proven to me that my modification works great for my needs/ expectations. The one section of trails I ride, my motor always got hot after the run , it now is " warm to very warm after the run....and the only thing I changed was drilling the holes and covering the holes with the heat sinks . Thats enough proof for my needs , but I understand if other people are skeptical.

 

[macribs]

Did you forget the links for those cooling fins?

 

[ebikedelight]

Did you forget the links for those cooling fins?

I posted the link on another thread...just go to ebay....and search aluminum heat sinks. The ones I got were 6" long. ..the heat sinks I ordered may not be suitable for everyone elses applications because you have to make sure you have enough clearance between the dropouts and the fins of the heat sink. In other words, everyone must measure how much space they have.,...you dont want heat sinks that have fins that stick out to far and hit your rear bike dropouts...or your disc brake rotor..or caliper..etc.

everyones application may be different ....I actually had more room for heat sinks with taller cooling fins...and If I did it over again, I would have ordered heat sinks with longer fins.

 

[macribs]

For anyone else wondering about what fins he used here it is

http://www.ebay.com/itm/131316806456?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

 

[ebikedelight]

For anyone else wondering about what fins he used here it is

http://www.ebay.com/itm/131316806456?_trksid=p2059210.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT

I cut them in half...so they are about 3" long pieces.

 

[ohzee]

wtb pics

 

[ebikedelight]

I actually ordered another set of heat sinks , with taller cooling fins . I wanted to have them on hand, just in case the current ones Ive used , dont perform like I want when I push my motor in the 2500 watt ranges, during the 100 degree summer heat and blaring sunshine . On my derauliar side of the hub motor , I can use heat sinks that have 3/4" tall fins and on the brake caliper side, I can even go with taller fins . Im guessing that taller fins , may give even better heat dissipation if needed. Im basically just experimenting with ideas, since it doesnt seem like many people have thought of doing this exact modification, its just trial and error on my part. ...but for now, the current heat sinks are working fine for my needs...but the weather in my area is only around 70 degrees and partly sunny.

 

[ebikedelight]

wtb pics

ill get my wife to take photos, as soon as she comes back from vacation. shes out of state visiting family.

 

[ebikedelight]

Is it definitely proven , that more heat comes from the freewheel/ cassette side of a rear brushless D.D. hub motor ? Ive seen people make that claim, but wasnt sure if it is
scientifically proven.

 

[dogman dan]

The freewheel gears would make a sort of crude heat sink fin. So will a brake disc on the other side, with a fairly close contact with the axle which heats up first as a motor warms.

To best see what your heat is inside a sealed hub motor ( no sensor inside I mean), take the temp of the axle, after protecting it from radiation cooling. What I mean is put your sensor on the axle stub, then cover it with some foam tape so that spot doesn't air cool so much. Right inside the dropout notch was my favored spot to attach the sensor. The axle will warm long before the motor shell does. Still quite possible to show the axle cool as a cucumber, while solder melts on your halls, if you push the motor hard enough though.

Think about it, for a hub motor, only the axle has a really direct metal connection to the coils. If I understand it right, your idea is cooling the magnets. This can still be good, since they have the smallest air gap to the hot coils of anything in the motor.

On a geared motor, not so good. Two air gaps before the outer shell on a geared, that's why they overheat easier than dd's. They cool slower.

 

[ebikedelight]

The freewheel gears would make a sort of crude heat sink fin. So will a brake disc on the other side, with a fairly close contact with the axle which heats up first as a motor warms.

To best see what your heat is inside a sealed hub motor ( no sensor inside I mean), take the temp of the axle, after protecting it from radiation cooling. What I mean is put your sensor on the axle stub, then cover it with some foam tape so that spot doesn't air cool so much. Right inside the dropout notch was my favored spot to attach the sensor. The axle will warm long before the motor shell does. Still quite possible to show the axle cool as a cucumber, while solder melts on your halls, if you push the motor hard enough though.

Think about it, for a hub motor, only the axle has a really direct metal connection to the coils. If I understand it right, your idea is cooling the magnets. This can still be good, since they have the smallest air gap to the hot coils of anything in the motor.

On a geared motor, not so good. Two air gaps before the outer shell on a geared, that's why they overheat easier than dd's. They cool slower.

Since the axle is made of steel , I would imagine it is a much weaker conducter of heat in this whole equation . Even though I have done this mod on 1 hub motor , I still have my wifes hub motor unmodded....and I plan to do this mod to hers....I just wasnt sure if the cooling results could be improved more , by making simple changes ...like changing placement of heat sinks , using taller fins , using pin heat sink design instead of flat fin design, etc.

They even make heat sinks out of copper , which is supposedly a better heat conductor then aluminum. It can get pretty complicated.

 

[cal3thousand]

This modification has resulted i me being able to push my 1000 watt motor, to 2500 watts and it only gets very warm..compared to it usually getting quite hot.

I appreciate your idea and I'm not shooting it down. But this particular claim that I quoted, doesn't really mean much. First, who said it was a 1000W motor? The motor manufacturer did and that is not standardized. Next, you don't tell us how long you can go 2500W and 'only gets very warm' is a very imprecise metric.

For example, a crystalyte HT3525 in stock format can do 2500W for 22 minutes before it 'overheats'. At 1000W, it will never 'overheat'.

The real question is whether your motor now has a higher capacity for heat shedding than previous.

BTW, what mystery motor are you working with? Any pics yet?

motor is a generic yescomusa 1000 watt D.D. rear hub motor off ebay for around $200 shipped with controller. Im not using stock controller , im using a Lyden which is pumping around 52 amps at 50 volts into the motor for certain sections of the trails I ride and hilly back roads that are made of gravel.

im not trying to convince anyone to do this mod...im just reporting that I came up with the idea, and am happy with the results. I personally would never try to run my motor at 2500 watts for 22 minutes , because I dont need that type of performance. I am comparing how hot my motor used to get, compared to how hot it now gets with the heat sink mods
running the same distance/ trails with similar throttle usage . My own experiments , although not 100 % precise, have proven to me that my modification works great for my needs/ expectations. The one section of trails I ride, my motor always got hot after the run , it now is " warm to very warm after the run....and the only thing I changed was drilling the holes and covering the holes with the heat sinks . Thats enough proof for my needs , but I understand if other people are skeptical.

I totally understand that you feel it's working for your setup. And that is important.

But you must have had some reason beyond 'telling a story' that drove you to share this. And that 'reason beyond' is to show someone else what you have found. Maybe eventually, we will take this in the community as a common mod for which you'd get credit. BUT, none of that happens unless we can prove it using a scientific approach. Unproven, it just goes into the pile of ideas that float around here and ultimately gets forgotten.

 

[ebikedelight]

[/quote]

I appreciate your idea and I'm not shooting it down. But this particular claim that I quoted, doesn't really mean much. First, who said it was a 1000W motor? The motor manufacturer did and that is not standardized. Next, you don't tell us how long you can go 2500W and 'only gets very warm' is a very imprecise metric.

For example, a crystalyte HT3525 in stock format can do 2500W for 22 minutes before it 'overheats'. At 1000W, it will never 'overheat'.

The real question is whether your motor now has a higher capacity for heat shedding than previous.

BTW, what mystery motor are you working with? Any pics yet?[/quote]

motor is a generic yescomusa 1000 watt D.D. rear hub motor off ebay for around $200 shipped with controller. Im not using stock controller , im using a Lyden which is pumping around 52 amps at 50 volts into the motor for certain sections of the trails I ride and hilly back roads that are made of gravel.

im not trying to convince anyone to do this mod...im just reporting that I came up with the idea, and am happy with the results. I personally would never try to run my motor at 2500 watts for 22 minutes , because I dont need that type of performance. I am comparing how hot my motor used to get, compared to how hot it now gets with the heat sink mods
running the same distance/ trails with similar throttle usage . My own experiments , although not 100 % precise, have proven to me that my modification works great for my needs/ expectations. The one section of trails I ride, my motor always got hot after the run , it now is " warm to very warm after the run....and the only thing I changed was drilling the holes and covering the holes with the heat sinks . Thats enough proof for my needs , but I understand if other people are skeptical.[/quote]

I totally understand that you feel it's working for your setup. And that is important.

But you must have had some reason beyond 'telling a story' that drove you to share this. And that 'reason beyond' is to show someone else what you have found. Maybe eventually, we will take this in the community as a common mod for which you'd get credit. BUT, none of that happens unless we can prove it using a scientific approach. Unproven, it just goes into the pile of ideas that float around here and ultimately gets forgotten.[/quote]


END QUOTES ::::::

MY RESPONSE :



Thats fine by me....ive proven it yields results on my end, which is most important to me. ..along with trying to think of other methods to improve it even further with minimum time invested . If other people are interested in this modification , but need more scientific data, then I guess they will have to perform the experiments to satisfy their curiousity. Since im not trying to sell a product for profit or force others to do this mod that has worked for me, its not my duty to go out and buy expensive equipment to provide further data to satisfy others curiousity. I posted this info , to share my mods with others that are interested in cooling modifications that dont involve

1 . messy oil/liquid cooling,

2 .open holes that allow dirt/ moisture in the hub

3. hooking up seperate cooling fans inside the hub......

since these seem to be the 3 main mods performed by ebike users to keep their motors cooler, I thought my mod would be nice to share.

 

[cal3thousand]

There's no need to buy expensive equipment here. You seem to have everything needed. I read that you have your wife's motor which has not been modified yet and that could serve as a baseline. Next all you would need is a temperature measuring method that can be used in a consistent fashion across the various modes.

Look, like I said, I appreciate the share. And since you seem unlikely to provide more data we will have to take your word that it works for you. I won't try to burden you further with scientific questions.

Maybe someone else that wants to further test this idea will take the scientific approach and measure their temperature readings in the 4 states:

• Without holes as stock
• Without holes, but with heatsinks
• With holes, but no heatsinks
• With holes covered by heatsinks

 

[ebikedelight]

There's no need to buy expensive equipment here. You seem to have everything needed. I read that you have your wife's motor which has not been modified yet and that could serve as a baseline. Next all you would need is a temperature measuring method that can be used in a consistent fashion across the various modes.

[/list]

I used a temperature measuring method....my hands , and prior knowledge of how uncomfortable it was to hold my hand on the side cover of the hub motor , before the mod , compared to how comfortable it is to hold my hand on the side cover of the hub motor after the mod . I rode the exact same trails , for the same distance in the same time frame to complete those trails, on a day where the outside temp was around 65 degrees . I understand my method may result in a few degrees of heat differences....when comparing pre mod to post mod....but is that really important here ? I think what is important, is that the temperature drop with the heat sinks, was so significant, that it took a uncomfortably hot motor, down to being a comfortably warm motor , when riding the same exact trail, under similar circumstances. For me to purchase additional equipment , just so I can have a digital readout of this temperature drop, is completely un-neccessary on my end of the equation.

I will do this mod on my wifes hub motor also ..in a few weeks ....but will try to think of possible ways which may allow this simple mod, to be even more effective...like different placements of heat sinks on the side covers..or using heat sinks with taller fins, etc.

 

[SlowCo]

I will do this mod on my wifes hub motor also ..in a few weeks ....but will try to think of possible ways which may allow this simple mod, to be even more effective...like different placements of heat sinks on the side covers..or using heat sinks with taller fins, etc.

When you do, can you make and post photo's of your mod at the building stages? That would help a lot for a newbie like me.

Kind regards,

SlowCo

 

[macribs]

I would think that using your method with fins and combine it with oil filled hub would be perfect. That might even let you push steep hills without overheating.

 

[ebikedelight]

I would think that using your method with fins and combine it with oil filled hub would be perfect. That might even let you push steep hills without overheating.

I was trying to avoid the mess and added weight involved with liquid filled hubs....aluminum heat sinks are very light..and neat/ tidy.....

im just trying to find the easiest, fastest, cleanest solution to keeping a hub motor cooler, when pushing it to its limits .

if I just ran this 1000 watt motor and 50 volts/ 20 amps max, all the time, then cooling mods probably wouldnt even be a issue.

 

[Nobuo]

I ordered 8 aluminum heat sinks with heat dissipation fins - the heat sinks are 6" long .

I first attached them directly to the face of each side of the hub motor using a small amount of heat conductive adhesive, towards the outer edges near the copper windings where most of the heat originates. I cut each heatsink down from 6 " to 3 " in length

The right side, I attached 4 of the heatsinks at the 12 - 3 - 6 - 9 o clock positions..the left side I attached 4 of the heatsinks
at the 2- 5 -8 -11 o clock positions.

I then took the ebike out on the dirt trails which normally gets the motor side casings hot to the point that its uncomfortable to hold my hand on it for more then 5 seconds. The heat sinks dissipated enough heat to allow me to hold my hand on the motor without discomfort , but I could still tell the motor was hotter then I wanted.

I came home, took the heat sinks off and then drilled several 1" holes exactly where each heat sink strip had been placed earlier and then reattached the heatsinks over thos holes. I thought the cooling effect would be greater if the heat from the inside of the motor, did not have to first go thru the aluminum side cover , then go thru the aluminum heat sink ....but
only have to go thru the heat sink to reach the cooling effects of the outside air. This was a success. I did the same run on the dirt trails, and the motor was only slightly warm .

This was a win win situation, in that the holes I made in both side covers, allows the heat to dissipate thru the aluminum heat sinks that cover the holes , but ensure that no dirt, water, humidity can enter the holes which are covered by the heat sinks .

This worked so well, I would imagine that eventually, manufacturers of hub motors will apply it to the design of their products. The aluminum heat sinks with fins, allow much better heat dissipation when they are used as the only barrier between the heat of the inside of the motor and the coolness of the outside air/ wind chill effects as the ebike is in motion.

It is an original idea, of course. nobody has though about close the holes, but that heat sinks on the inner rims motor area sounds easier and interesting also.

Could you at least make a easy fast paint draw of the position of holes and heat sinks sizes?

 

[ebikedelight]

ill get photos up as soon as my wife returns home.

she has the digital camera with her.

 

[ziltoid81]

when my wife returns from vacation..ill try and get some photos uploaded...some people also wanted some close up photos of how I built and attached my battery holder to my ebike frame...so Ill try and get that done also.

Sorry i didnt read all the posts.....but why did you build your fork in....... the wrong way?

In bikeforums there are threads about this......they share pictures of this to laugh about it.
But maybe you did this on purpose.......