Air Cooling my x5

[markcycle]

you are going to put 40W of fans in there?

you think thats gonna help you more than it hurts your battery?

this is the point of air cooling.

That's the point to the experiment, but I think yes. We are talking drag racing bike, motor to the max. BTW the lights on my motorcycle are a 100 watts 150 with the brake light. I'll burn 40 watts anytime to avoid thermal shut down and wait on the side of the road for a half hour for it to cool off. The fans can be thermally controlled to turn on at a certain temp. If most of your heat is generated at startup, what other choose is there ( if your committed to a certain motor)? BTW I have 4KW of battery in my bike.

 

[potatonet]

well then I think you are set, Im only rolling 1.25kw right now so 40 watts is something to take note of

 

[tostino]

well then I think you are set, Im only rolling 1.25kw right now so 40 watts is something to take note of

Well it depends on how much the lowered temperature increases motor efficiency. There is a pretty good chance that lowering the temp will affect the motor in such a way that it completely out weighs the power your spending on active cooling.

If you are pushing 3000 watts to your controller, and your motor is running at 82% efficiency, you are getting 2460 watts going to motion, and 640 watts wasted as heat.
And again, if you are pushing 3000 watts through your controller, 40 watts in active cooling fans, and that increases your motor efficiency to 84%, you are than getting 2553 watts as forward motion, and only 446 watts as heat (with 40 being used for cooling).

 

[markcycle]

well then I think you are set, Im only rolling 1.25kw right now so 40 watts is something to take note of

Well it depends on how much the lowered temperature increases motor efficiency. There is a pretty good chance that lowering the temp will affect the motor in such a way that it completely out weighs the power your spending on active cooling.

If you are pushing 3000 watts to your controller, and your motor is running at 82% efficiency, you are getting 2460 watts going to motion, and 640 watts wasted as heat.
And again, if you are pushing 3000 watts through your controller, 40 watts in active cooling fans, and that increases your motor efficiency to 84%, you are than getting 2553 watts as forward motion, and only 446 watts as heat (with 40 being used for cooling).

Well said. Those of us that have used a X5 to it's extreme know the increase winding resistance due to temperature reduces performance or as you said efficiency, to the point that there is a noticeable performance hit. If active fan cooling can reduce this effect enough by maintaining a lower wire temp then its worth the watts.

Mark

 

[John in CR]

Steveo,

Don't forget the side covers also support all the weight, and the metal quality is suspect, so if you weaken them with holes I'd add back some kind of support ribs. If on the interior the ribs could take the form of the vanes previously mentioned, and stimulate a turbulent air flow near the windings where it's needed.

Considering the fabrication effort involved in creating effective air cooling at the low rpms of hub motors I'd recommend a liquid cooling approach that has the potential to be far more effective for cooling and keeps the motor sealed. Plus I think everyone wants to see a liquid cooled high powered hubby.

If you're stuck on air cooling, I'd first try without vents. Instead try some interior vanes to both add interior surface area and create a turbulent interior air flow. Then increase the surface area on the exterior as well with fins or a large disk on each cover.

John

 

[vanilla ice]

I'll wager just drilling some holes would get 75% of the way to the cooling of the full ducts and ribs and fans treatment.

I'm at a loss trying to think up a good internal retention system for small filters. Maybe something that clips in to the round holes, that way you wont need to worry about it.

 

[potatonet]

if there are no holes then the air is going to remain stagnant. you need a hole...

liquid cooling would be great, anyone thinking about making a custom axle that has really large threads and no stepdown?

then you could probably get away with running the liquid in down the center of the axle and into some custom radiator/s inside the wheel then back out the other side.

it really would not be hard if I only had a decent CNC mill...

Im thinking about making my own stator for my next motor because these CL ones suck donkey huevos.

next time I will use strain hardened aluminum pressed into stainless and then wound with copper (just got to get back home)

 

[stew007]

This is how I did my 408, I run over 2000watts through this motor without it over heating. Before I drilled the holes, it over heated and lost power after only a few miles, efficiency took a big hit too. Now it behaves like a totally different beast 8) fresh crisp power on tap all the time, after a 20 mile ride the motor is just slightly warmer than ambient to the touch, before drilling the holes it was scalding. I've done over 500 miles now without a problem, no problems of dirt, but I guess I dont really use it during rainy days, but if you could get a few weep holes close to the outside of the can then I would think any moisture would exit at speed, so not be much of a problem. The benefits so far have been huge, from a 600w motor to a 2000w motor

ps, I counter sinked the holes on the outside, so the air friction on the outside of the plate draws the warm air out, a bit like a venturi. This was done on both sides of the motor.

 

[vanilla ice]

One guy's swiss cheesed motor is worth 1000 posts.


I bet I could do that without removing the side plates.

 

[Almasi]

This is how I did my 408, I run over 2000watts through this motor without it over heating. Before I drilled the holes, it over heated and lost power after only a few miles, efficiency took a big hit too. Now it behaves like a totally different beast 8) fresh crisp power on tap all the time, after a 20 mile ride the motor is just slightly warmer than ambient to the touch, before drilling the holes it was scalding. I've done over 500 miles now without a problem, no problems of dirt, but I guess I dont really use it during rainy days, but if you could get a few weep holes close to the outside of the can then I would think any moisture would exit at speed, so not be much of a problem. The benefits so far have been huge, from a 600w motor to a 2000w motor

ps, I counter sinked the holes on the outside, so the air friction on the outside of the plate draws the warm air out, a bit like a venturi. This was done on both sides of the motor.

Nice to hear this from someone who did it

I guess I know what to do next

Robin

 

[steveo]

This is how I did my 408, I run over 2000watts through this motor without it over heating. Before I drilled the holes, it over heated and lost power after only a few miles, efficiency took a big hit too. Now it behaves like a totally different beast 8) fresh crisp power on tap all the time, after a 20 mile ride the motor is just slightly warmer than ambient to the touch, before drilling the holes it was scalding. I've done over 500 miles now without a problem, no problems of dirt, but I guess I dont really use it during rainy days, but if you could get a few weep holes close to the outside of the can then I would think any moisture would exit at speed, so not be much of a problem. The benefits so far have been huge, from a 600w motor to a 2000w motor

ps, I counter sinked the holes on the outside, so the air friction on the outside of the plate draws the warm air out, a bit like a venturi. This was done on both sides of the motor.

now thats what i'm talking about

-steveo

 

[potatonet]

I will be doing this to a motor sooner or later, good job,

I never though about drilling on the edges! that would provide the scoop!

 

[Zoot Katz]

. . .

ps, I counter sinked the holes on the outside, so the air friction on the outside of the plate draws the warm air out, a bit like a venturi. This was done on both sides of the motor.

now thats what i'm talking about

-steveo

Drillium? What are you, a weight-weenie all of a sudden?

You need a radiator, pumps and yards of tubing.
Play for the complications.

 

[potatonet]

. . .

ps, I counter sinked the holes on the outside, so the air friction on the outside of the plate draws the warm air out, a bit like a venturi. This was done on both sides of the motor.

now thats what i'm talking about

-steveo

Drillium? What are you, a weight-weenie all of a sudden?

You need a radiator, pumps and yards of tubing.
Play for the complications.

please explain this whole post, as it made no sense

 

[dogman dan]

Thanks for the real world, I tried it and it worked, post. I think even some fine screen would keep enough of the dirt out. Just something to keep the rocks above .5 mm out. Some clay powder on the coils won't hurt, and the bearings are sealed.
For those using a bit less power, less holes might work fine.

On my aotema motor testing, I will first simply try to melt it, riding in 100F temps for 500 miles or so. Then if it survives, I will see what the effect of more and more air holes is, to find the smallest practical vent hole for normal 36v operation in the desert.

I wouldn't want to risk hundreds of dollars to avoid popping the covers, it's not that hard, so take off the cover to drill.

 

[davespicer]

I never though about drilling on the edges! that would provide the scoop!

If little plastic scoops could be fabricated (molded?) and glued around each hole, that'd be even better. The ones closer to the hub would face "forward" - their open end facing into the airflow as the bike moves forward - and the ones farther out would face away from the airflow so the venturi effect would help pull hot air out of them. Even if they could only be a quarter-inch high, seems like they might help...

 

[Link]

liquid cooling would be great, anyone thinking about making a custom axle that has really large threads and no stepdown?

I'm gonna drill through the axle of a 406 tomorrow if I can find the damn thing. What's that count for?

I'll be lucky to get 70GPM through that thing, though.

 

[michaelplogue]

How about some trimmed 1/2" pvc pipe elbows held on with some really strong epoxy........

http://plumbing.gillroys.com/PVC_&_Plastic_Pipe/PVC_elbows/1/2_IN_PVC_FIPXS_90D_ELBOW-s411003.html

http://plumbing.gillroys.com/PVC_&_...lbows/1/2_IN_CPVC_90D_STRT_ELBOW-s410807.html

 

[steveo]

How about some trimmed 1/2" pvc pipe elbows held on with some really strong epoxy........

http://plumbing.gillroys.com/PVC_&_Plastic_Pipe/PVC_elbows/1/2_IN_PVC_FIPXS_90D_ELBOW-s411003.html

http://plumbing.gillroys.com/PVC_&_...lbows/1/2_IN_CPVC_90D_STRT_ELBOW-s410807.html

Forced air induction lol!! nice .. very extreme!! you could even put filters in those things .. like sponge!!..

think is will it clear the bike frame

-steveo

 

[potatonet]

this is why I said to use the scoops from an RC car... forced air

 

[monster]

under what circumstanses would you need to do this to an X5 ?

 

[monster]

you would need cooling for the controller way before you need cooling for the motor, right?

 

[Doctorbass]

you would need cooling for the controller way before you need cooling for the motor, right?

With my setup i definitively need to cool the motor!.. my controlerl stay under 40 celsius and my motor up to 160!

Cooling my motor would increase power and decrease energy lost in heat.

At temp 70-80 and up celsius i noticed a signifianct loose of power when the resistance of the winding increase.

I like the air cooling idea but the dust, sand and little rock and rain would certainly not help the motor life...

Think about that.. the hub motor manufacture consider important to put axel bearing with rubber sealant.. imagine....

Doc

 

[potatonet]

Docs logic wins again...

 

[The Stig]

What if you partially flooded the motor with oil, like Reid Welch does. When the motor is spinning all the oil would be around the outside and you could fill it just enough so that the surface of the oil would be touching the stator. At the moment it seems the only place the heat can escape the stator is through the axle, and a bit of convection between stator and casing. If oil was touching the outer surface of the stator that would be a much bigger area than the axle and there would probably be a lot of turbulence in that oil ---> better heat transfer.

The mod on the previous page looks good, very easy. Using oil would have the advantage of keeping water and dust out, although dust doesn't really matter.