Joppo said:
That should work. I'd use the lowest viscosity you can find.
Oil cooling your hub- NOT snake oil!
- Thread starter Spicerack
- Start date
That should work. I'd use the lowest viscosity you can find.
feedback!
50 ml 10-40 semi-synthetic motoroil!
1. lower and much smoother noice from motor.
2. can feel faster and better heat transfer to the covers on the motor.
3. not afraid of moist or water.
4? i hope i dont have to open the hub so much anymore, i ride 20 kilometer almost every day and i am always afraid to run it dry (have done it before with not so good results)
this is a huge upgrade for me and my bike, i dont understand all the negativity with oil in hub motors.
if u got the tools and know how, its not hard to get a good seal.
50 ml 10-40 semi-synthetic motoroil!
1. lower and much smoother noice from motor.
2. can feel faster and better heat transfer to the covers on the motor.
3. not afraid of moist or water.
4? i hope i dont have to open the hub so much anymore, i ride 20 kilometer almost every day and i am always afraid to run it dry (have done it before with not so good results)
this is a huge upgrade for me and my bike, i dont understand all the negativity with oil in hub motors.
if u got the tools and know how, its not hard to get a good seal.
Joppo said:
So you have no leaking at all... What exact motor did you add oil too? Make, model, year, bought from...
Want to tell people how to do it? justin was saying most people are having trouble with oil leaking. It probably depends on the motor. As you said it also depends on the know how, so feel free to re-write / write your own version of this:
https://endless-sphere.com/forums/viewtopic.php?f=2&t=37972&p=729361&hilit=noob+guide#p729361
Less heat on full throttle than on 3/4 throttle:- -
I would assume that on less than full throttle the controller is pulsing the current or voltage to modulate/control the wattage supplied. This pulsing I think may be generating more eddy currents in the metal cores and lead to heat generation.
Another important point of physics in the splash oil cooling method and why it works -- Better direct conduction of heat to the oil and then transfer to the outside surface of the hub is clearly very important but of equal importance and significance is the much much greater THERMAL CAPACITY (ability to absorb and hold heat per unit vol) of oil compared to air. I do not know where exactly Spicerack has placed his temperature probe but if it is at the windings, then this nicely illustrates the effect of the increased thermal capacity of oil compared to air giving him his temperature cycle fluctuation. The temp goes up initially on acceleration but then rapidly drops as the heat is absorbed by the oil, eventually reaching a steady state differential between the windings-oil-hubsurface (at a steady throttle). It is acting like a liquid heat sink.
One might think a thicker and higher thermal capacity fluid will be always better but the trade offs to consider are:
Denser oil more drag; lighter oil lower (essentially temporary) heat absorbtion but less drag and better turbulence circulation of oil to transfer heat to the hub outer casing. There will be an optimum balance point between various factors as in all engineering decisions.
WR
I would assume that on less than full throttle the controller is pulsing the current or voltage to modulate/control the wattage supplied. This pulsing I think may be generating more eddy currents in the metal cores and lead to heat generation.
Another important point of physics in the splash oil cooling method and why it works -- Better direct conduction of heat to the oil and then transfer to the outside surface of the hub is clearly very important but of equal importance and significance is the much much greater THERMAL CAPACITY (ability to absorb and hold heat per unit vol) of oil compared to air. I do not know where exactly Spicerack has placed his temperature probe but if it is at the windings, then this nicely illustrates the effect of the increased thermal capacity of oil compared to air giving him his temperature cycle fluctuation. The temp goes up initially on acceleration but then rapidly drops as the heat is absorbed by the oil, eventually reaching a steady state differential between the windings-oil-hubsurface (at a steady throttle). It is acting like a liquid heat sink.
One might think a thicker and higher thermal capacity fluid will be always better but the trade offs to consider are:
Denser oil more drag; lighter oil lower (essentially temporary) heat absorbtion but less drag and better turbulence circulation of oil to transfer heat to the hub outer casing. There will be an optimum balance point between various factors as in all engineering decisions.
WR
guys , amazing thread ! i'm totally going for that upgrade on my new 2k motor . i would like to see how much juice i can harvest out of this baby .
anyway can you please help with the EXACT type of oil that will not harm ? also what size of the vent should i do ? ( i want to avoid it ) . and how can i effectively seal the axle and the covers so the oil will not escape ? ( hopefully without drilling a vent ) .
anyway can you please help with the EXACT type of oil that will not harm ? also what size of the vent should i do ? ( i want to avoid it ) . and how can i effectively seal the axle and the covers so the oil will not escape ? ( hopefully without drilling a vent ) .
just researched the topic , and understood that oil cooling is irrelevant when theres ferrofluid solution . does anybody know how good should be the side covers sealing when filling ferrofluid ? they say only on very high speeds this liquid start to squeez out .
Ohbse
10 kW
levleon13 said:
Yes - Side covers do need to be sealed when using FF. Absolutely agree than FF has almost entirely displaced oil cooling, It's *much* less messy.
Ohbse
10 kW
Remove the cover using a puller or one of the other home brew methods, make sure to retain the original cover index to the hub, use a razor blade to scrape all of the mating surfaces clean and smooth. Debur with a small file if there are any protrusions or casting inconsistencies. Clean with isopropyl alcohol. Apply a *thin* bead of silicone gasket maker, any automotive store will have something suitable. Use a glove to smear this into an even *thin* layer on both mounting surfaces and then replace the cover. Twist slightly in place to ensure a clean seal, align and replace the screws. You should have a small amount of consistent squeeze out around the circumference of the hub. Don't use too much, a little dab''ll do ya. Repeat for the other side.
While you have the brake side cover off I would recommend using a 1.5mm or 2mm drill bit drill THROUGH one of the disk rotor bolt holes, you can use this to fill the hub. Make sure to clean up when you're done and use loctite Blue or similar on your bolt threads to ensure no leaks there.
While you have the brake side cover off I would recommend using a 1.5mm or 2mm drill bit drill THROUGH one of the disk rotor bolt holes, you can use this to fill the hub. Make sure to clean up when you're done and use loctite Blue or similar on your bolt threads to ensure no leaks there.
FlyingFinn
100 W
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- Jan 3, 2018
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- 210
I’m going to buy a QS273. I know many people prefer ferrofluid these days but my idea is to rust-proof it easily as well.
So what do you think, if I seal the cover seam with silicone, drill a small hole and put some AT-oil inside? No need to open the motor while cooling and rust-proofing is provided easily.
So what do you think, if I seal the cover seam with silicone, drill a small hole and put some AT-oil inside? No need to open the motor while cooling and rust-proofing is provided easily.
Emmett
10 kW
I use castor oil in my H4040 motor. No odour like ATF and much easier to clean away any leaks. The process to seal the side covers is described a few posts back. Be sure to use an oil resistant silicone sealant.FlyingFinn said:
To avoid the side covers coming loose for rough offroad conditions, something I did was to use loctite on totally clean threads on the side plate screws. To do that I removed the screws when sealant had cured, and installed new clean screws with loctite.
To seal the hub motor properly you also must use the same sealant on the wire slot in the axle. I replaced my wires with thicker and more flexible wires, and smothered them in sealant before laying them back in the slot. I used heat-shrink wrap to compress the wires and sealant into the slot. Once cured I removed the shrink tape and assembled with bearing and side cover.
Obviously you must have sealed bearings. A little oil will leak out at times between the axle and bearing inner bore.
I added a 1mm breather hole near the chain sprocket. For oil fill/drain I have a M5 bolt tapped into the right side cover plate, out near the magnets. Fiber washer to seal it and bolt short enough so it wont touch the magnets.
I also have one of those hub-ring cooling heat dissipation fins. Forget the name. But highly recommend it. I pump 6500W through my H4040 and never have overheating issues.
FlyingFinn
100 W
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- Jan 3, 2018
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- 210
Emmett said:
Thanks for the info! Only issue with castor oil is the viscosity in cold. It can get -20C around here so best option is still to use normal Mobil1 synthetic car oil or AT-oil?
Emmett
10 kW
Wow, -20 air temps! Yeah, too cold for castor. If not ferro-fluid, then you better use a mineral oil. Just a bummer because it stinks when it leaks.FlyingFinn said:
Castor oil is awesome. It mostly washes off with the water hose, then a rag wipe over the rim and spokes and it's all gone. Also castor on the rear brake rotor doesn't reduce stopping force much at all, in my experience.
FranBunnyFFXII
10 mW
- Joined
- Aug 14, 2019
- Messages
- 31
Hey guys, I've got a 48Volt 26amp 1000watt generic hub motor, that I'm upgrading to 60volts Battery 30amp controller next year, and I'm looking to introduce cooling to it.
Statorade is too expensive for me, I'm trying to do everything on a budget. A bottle of 5w30 is less than 5 bucks on amazon. So I wanna go with that.
I've been reading this whole thread over the past hours and the hub i have is a clone chinese DD hub, and I have no idea how it relates to much of the plantary gear or other motors people are running.
I was going to just drill a hole closest to the axel as i can, and inject oil and tape up the hole. What should I plug the hole with? I can't do a vent because I ride in the rain quite often. I cant afford water getting into my motor.
Do I have to worry about leaks?
Any advice?
Statorade is too expensive for me, I'm trying to do everything on a budget. A bottle of 5w30 is less than 5 bucks on amazon. So I wanna go with that.
I've been reading this whole thread over the past hours and the hub i have is a clone chinese DD hub, and I have no idea how it relates to much of the plantary gear or other motors people are running.
I was going to just drill a hole closest to the axel as i can, and inject oil and tape up the hole. What should I plug the hole with? I can't do a vent because I ride in the rain quite often. I cant afford water getting into my motor.
Do I have to worry about leaks?
Any advice?
Something to remember is that it depends on what exactly you want to achieve, whether a cheaper solution will do it, or if you need to go the higher cost route.
So...how much hotter does your motor get than it is supposed to?
If it isn't getting hot, you don't need to do any of this stuff.
Water will get in (probably already has--open it up and you may see rust in there); you can't truly seal up a hubmotor, and most of them don't come correctly sealed from the factories. They'll seal up the covers sometimes, which just traps the water that does get in there (via axle, wires, bearings). We see a motor now and then on the forum that got enough water in over time to corrode the magnets to the stator laminations, even though it was "sealed".
But the oil, splashing around in there, will keep things coated, so water that does get in probably wont' stick to stuff, as long as it was dry when you put the oil in. But the water will still be in there, once it does get in.
To let the water get out, the motor has to have some kind of ventilation. The best way is incompatible with an oil-fill, and that's to drill a tiny hole (or few) around the outer circumference of the side covers, at the same level as the magnets, so water that is at teh bottom can drain out, and better air exchange can occur to let the hub dry out as it warms up inside during use.
THere are vents (goretex? sorry, don't remember, but it's in this thread somewhere, or in the "definitive testin of heating and cooling of hubmotors" thread) you can install in a hole drilled near the axle, that let air thru but not liquid water. they thread into the hole, so you can unscrew them to refill oil if it leaks out.
Sealing it to keep the oil in depends on how much oil, and how much you tip the bike to the side and how long it stays that way, etc. The axle is the leaky spot, usually.
So...how much hotter does your motor get than it is supposed to?
If it isn't getting hot, you don't need to do any of this stuff.
Water will get in (probably already has--open it up and you may see rust in there); you can't truly seal up a hubmotor, and most of them don't come correctly sealed from the factories. They'll seal up the covers sometimes, which just traps the water that does get in there (via axle, wires, bearings). We see a motor now and then on the forum that got enough water in over time to corrode the magnets to the stator laminations, even though it was "sealed".
But the oil, splashing around in there, will keep things coated, so water that does get in probably wont' stick to stuff, as long as it was dry when you put the oil in. But the water will still be in there, once it does get in.
To let the water get out, the motor has to have some kind of ventilation. The best way is incompatible with an oil-fill, and that's to drill a tiny hole (or few) around the outer circumference of the side covers, at the same level as the magnets, so water that is at teh bottom can drain out, and better air exchange can occur to let the hub dry out as it warms up inside during use.
THere are vents (goretex? sorry, don't remember, but it's in this thread somewhere, or in the "definitive testin of heating and cooling of hubmotors" thread) you can install in a hole drilled near the axle, that let air thru but not liquid water. they thread into the hole, so you can unscrew them to refill oil if it leaks out.
Sealing it to keep the oil in depends on how much oil, and how much you tip the bike to the side and how long it stays that way, etc. The axle is the leaky spot, usually.
FranBunnyFFXII
10 mW
- Joined
- Aug 14, 2019
- Messages
- 31
It doesn't overheat now because it's running at spec, but I'm overvolting it by 25% and the EBIKE sim says it will over heat.
Since the overvolting and new battery I am doing is intended to run 30 amps over 26, and 60volts over 48, and partially intent at running extended periods of time at 30mph+. Cooling is Safe guard over requirement. It will need cooling, just not as much as other builds.
Peak output 1800 Watts, on a "1000watt"(really 1250), system. Top speed of 37mph, Some sustained 35mph road time.
So I'm thinking drilling a hole, and using 5W-30, since its $4.50 a quart. That's enough to do a 1/3rd of the hub fill, keep it cooled better, and have enough for refilling the hub for a long time.
I'm mostly just worried about stopping leaks, and making sure the oil im looking at doesn't eat the insulation.
A quart of oil is way cheaper than a statorate syringe.
Since the overvolting and new battery I am doing is intended to run 30 amps over 26, and 60volts over 48, and partially intent at running extended periods of time at 30mph+. Cooling is Safe guard over requirement. It will need cooling, just not as much as other builds.
Peak output 1800 Watts, on a "1000watt"(really 1250), system. Top speed of 37mph, Some sustained 35mph road time.
So I'm thinking drilling a hole, and using 5W-30, since its $4.50 a quart. That's enough to do a 1/3rd of the hub fill, keep it cooled better, and have enough for refilling the hub for a long time.
I'm mostly just worried about stopping leaks, and making sure the oil im looking at doesn't eat the insulation.
A quart of oil is way cheaper than a statorate syringe.
The one at http://ebikes.ca/simulator ?FranBunnyFFXII said:
It's a pretty good sim, when Iv'e compared what it says to what I actually see, so you can probably trust that it's right.
But the question is--how long does it say it will take, under the worst conditions you'll experience, to overheat?
And...is there anything you can change in the sim that will prevent the overheat? That would also be practical to do in reality?
I only ask because when oil leaks it's REALLY messy. And it can contaminate your brakes, making them useless when you need them if you don't know it's happened. (doesnt matter if they're disc or rim).
.
Extra cooling never hurts.
It isn't always necessary, but it sure is handy to have when it turns out to be.
I have overheated geared hubs before, but pretty much only when running more than twice the power it was meant for, for a couple of miles or more. Even then, the halls just temporarily malfunctioned, and worked again once it cooled off, IIRC. I have only overheated one DD hub, by running it very slow at high load with stops and starts. IIRC it killed the hall sensors, but worked once I replaced them.
I don't know what the oil will do to any of the interior components. Probably nothing...but I don't know. I used ATF in a short experiment with that geared hub, but it leaked like a sieve and got on the rim brakes, etc. Intended to continue the experiment but didn't; cant' remember why. It's in the DayGlo Avenger thread somewhere, probably near the end.
FranBunnyFFXII
10 mW
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- Aug 14, 2019
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- 31
Yeah that one.
From what im seeing in the Sim, my bike is a 9c clone motor 2706, and it will over heat at 23 minutes at top speed.
What can be done to prevent it from overheating? Statorade or Oil.
I'll need to oil cool it if I plan on doing extended distance, which I do.
From what I'm seeing in this thread, the oil will take care of it as well.
It will hit thermal damaging levels of heat after a short while I'm, not entirely sure what motor to use in the sim but all of them reach red temps and, I'd rather be safe than sorry.
From what im seeing in the Sim, my bike is a 9c clone motor 2706, and it will over heat at 23 minutes at top speed.
What can be done to prevent it from overheating? Statorade or Oil.
I'll need to oil cool it if I plan on doing extended distance, which I do.
From what I'm seeing in this thread, the oil will take care of it as well.
It will hit thermal damaging levels of heat after a short while I'm, not entirely sure what motor to use in the sim but all of them reach red temps and, I'd rather be safe than sorry.
If you can seal the motor cover well and use just enough oil fill the magnet gap when it’s running it might work out ok.
With a direct drive motor you don’t need to use too much oil. It will spread out when the motor runs sort of like ferrofluid.
With a direct drive motor you don’t need to use too much oil. It will spread out when the motor runs sort of like ferrofluid.
FranBunnyFFXII
10 mW
- Joined
- Aug 14, 2019
- Messages
- 31
fechter said:
What I'm really interested in is the liquid fill of the entire motor, as the Stator doesnt rotate to fling the oil everywhere like a crankshaft would. Rather the case rotates.
Does the force of a rotating drum with no edge to propel the liquid counteract the force of gravity?
How much of the oil is flung around?
ect. ect.
I cant find a fluid dynamics simulation to answer this question.
John in CR
100 TW
FranBunnyFFXII said:
Over filling creates more heat. The oil follows the rotating shell pretty well, so do it in a manner that you can experiment with different amounts of oil fill. I seem to recall from others' results that 10%-25% fill worked best, but I'm sure that varies by motor.
FranBunnyFFXII
10 mW
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- Aug 14, 2019
- Messages
- 31
John in CR said:
I actually got my friend to download me a study about horizontal cylinder rotation and liquid and found some other resources.
It turns out about 1/4th volume fill will be only about as much as I should need.
I'll have to calculate the actual volume of the drum case of the motor, but yeah it looks like I wont need much oil at all.
This is 1/4th fill with dyed water, since oil is more viscous, this is a fairly good reference for the oil fill I can expect at high RPM where the cooling will be most necessary.
