Improved Weatherproofing Idea

I had the cover off my 1000W GM hub the other day and I was thinking about my old 350 watt hub motor that is pretty much a pile of rust. I fitted it with a studded tire and used it to get around in Potsdam, NY when I was going to school up there (cold, salty, and sandy). They don't even use a terribly amount of salt because it gets too cold for the salt to be effective. But nevertheless I don't want me new motor to end up a pile of rust. I was wondering if there was a way to avoid this other than not riding it in any type of weather...

I was thinking; It might be worth a try to pack the hub motor itself with waterproof grease. This shouldn't affect performance terribly and would likely make the motor much more resistant to corrosion due to moisture. Also, it probably would warrant some extra sealing around the axle itself to prevent the grease from escaping and contaminants from entering.

I figure this would require regular maintenance of disassembling the motor and cleaning thoroughly and re-packing, because I'm sure the grease would eventually become contaminated but I imagine this could drastically reduce corrosion in the motor itself in extreme conditions.

Any thoughts? Are there any 'show stoppers' that I have overlooked?

grindz145 said:

...my old 350 watt hub motor that is pretty much a pile of rust.

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Awww crap. I am only familiar w/separate motors, sprockets and chain. I have an old Crystalyte hub motor to play with and it looks like I'll finally have it on the road this winter. And in my `hood winter means inches of salty slush... So I am not happy to read about rusty hubs! Seems like a real argument against... Had a quick google for greases though, and there does seem to be some pretty nifty stuff out there. I'll be interested to hear what others here can add about greasing up a hub motor. I can't imagine it's a significant performance "hit" versus the extra electrons needed for pushing the bike through slush and snow...
tks
Lock

maybe you can use a sactaficial anode? on ships they stick a lump of magnesium on the hull somewhere and it rusts in preference to the hull. it electro-chemistry.

or you could paint it?

.

That is one nice thing about not using a hub motor is that you could protect it alot easier. Paint won't really work because of the components we are talking about (laminated windings. bearings/ etc).

As far as sealing goes, if the whole motor is packed with grease only a minimal amount of water would make its way in and the alternative is loosing all the grease. I am thinking like a CV boot in a car as a use-case...

nutsandvolts said:

My motor has been through slushy salt hell, and though parts of it appear to be rusty, it still works the same.
I'm not sure I'd try to seal it because water WILL get in there then become trapped.

An apparent solution would seem to be sealing the motor against water entry, but at least from our experience this is not the case. A disproportionately high number of these failures occured on motors that had had the wire entry to the hub thoroughly sealed with silicone or other goop. Rather than keep the motor dry, water inevitably leaks in and is then trapped inside. Unless you can be sure that you have sealed 100% against water entry, it would be better to leave the wire port as is and to always store the bike indoors, preferably in a warm place, after riding in the rain so that the hub innards get a chance to dry out.

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Troubleshooting

People who live in salt slush hell know that you can't avoid the stuff, the key is washing it off and letting it dry.

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This is so true though... there really is no saving grace when it comes to salt... hmmm

I wonder if there is some type of potting (possibly thermal potting) which you could coat the windings and H/E sensors in to avoid corrosion there.. Even though there is no avoiding the salt, there may still be room for some improvement.

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problems I see are:
The break down of the insulation and glue due to the solvent action of the grease

Friction caused by the grease viscosity acting on the airgap. Oil is a lube only when the viscosity is overcome, untill then it sticks things together pretty well. The airgap is so small, and grease is so well effective against shearing, that it would be difficult to spin the motor efficently.

Weight. it woudl take a couple pounds of grease to fill one of these things.

Heat retention. The grease would pull the heat away from critical areas, but it would also be pulling it away from the sides, meaning it would hold heat and cool less efficently.

and last of all, Leaks. Grease is a fluid, more so when hot. if the seals can't keep water out, they can't keep the oils from the grease in. This bike would leak more than an MG, and sling grease as the tire spun.

you might be better off either adding drains to let water out, or designing better seals to keep it out.

I love this forum. This is all really great, well-formed feedback. How about a small amount of conformal coating on the windings and hall effect sensors, and some type of draining solution... I still have the urge to want to seal off the motor. I think purely packing the motor with grease is probably out though...

You could try Electrolube DCA Modified Silicone Conformal Coating. It comes in a spray can so it's easy to apply. I was concerned about its effect on heat dissipation so I emailed the manufacturer and they assured me that it would be negligible.

You spray it on and leave it to dry for 2 hours. Then you put it in the oven for 2 hours at 200F.

Here's the datasheet.View attachment DCA.pdf

Mike1 said:

...Then you put it in the oven for 2 hours at 200F.

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Not sure ya want to do that to rare earth permanent magnets?
tks
Lloc

You don't have to bake it but it improves its resistance to chemicals.

Hub motors run at 250 F all the time.

Ried did something similar awhile back, I recall he had filled a hubmotor with some kind of oil. Was talking about riding underwater and stuff.

I also recall some pacific northwest guys talking about how water gets into hub motors as vapor but can't get out later. Some discussion talked about condensation when a warm moist hubmotor was wheeled outside into the cold winter from a house that was humid. They seemed to think a vent hole that could be opened to let water vapor out of a motor when it was warm after riding would help. It made sense to me, once a drop of water gets in, it would tend to stay in there. But a vent in a hot motor would make the vapor leave the motor, then stop up the vent again when the motor cools off. Maybe two vents, so one sucks in dry air while the warm moist stuff convects out the top one.

Mike1 said:

You could try Electrolube DCA Modified Silicone Conformal Coating. ]

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This is exactly what I had in mind. When you said 200 I thought 200C (which I shouldn't because Im from the US but that's what engineering will do to you ) 200F is not a big deal and I think it would be definitely worth doing. It dosn't make a terrible mess like many of the alternatives ive suggested either.

Doing this, in conjunction with a vent (perhaps one that would somehow allow moisture to escape but would discourage water from entering). Ill have to think about what something like that might look like...

I haven't tried it, since I don't ride in the rain, but ACF-50 seems to have a good reputation.

ACF-50 ANTI-CORROSION FORMULA
HOW IT WORKS: ACF-50, Anti-Corrosion Formula, is a state of the art, anti-corrosion lubricant compound, specifically designed for the Aero Space Industry. It is an ultra Thin Fluid Film Compound (TFFC) that actively treats metal using advanced polar bonding technology. As seen from the diagrams, ACF-50’s synthetic inhibitors and active chemistry penetrates through the oxide deposits (white powder) to the base of the corrosion cell where it emulsifies, encapsulates, and then lifts the electrolyte away from the metal surface. ACF-50 then allows this moisture to evaporate while providing an atmospheric barrier that prevents further moisture contact. With the electrolyte removed the corrosion process is halted. ACF-50 actively penetrates and “creeps” into the tightest seams, lap joints, micro cracks, and around rivet heads, displacing moisture and other corrosive fluids (orange juice, coke, coffee, salt water) in these corrosion prone areas. ACF-50’s thin film acts like an “OFF SWITCH” for corrosion remaining effective for up to 24 months.

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If a small vent hole was drilled and covered with an adhesive patch then that would allow for occasional re-application.

hell yeah. I think I am more interested in ACF-50 for my gas(bad word) motorcycle and/or car ... This looks like it is worth a try for sure

For the vent: I was thinking maybe something like a grease fitting or break bleeder nipple. This could allow opening and closing of the valve, but more importantly you could attach a tube and feed it around is such a way that it would not allow water in easily but would let moisture out.

I think the Canadians were thinking in terms of a hole and a rubber plug to fit into it when out running. The idea was to just open it about once a month. Some rusty motors were running with a lot of liquid water inside em after 6 months of daily riding in rain. I think a bit of gorilla tape, or aluminum duct tape would cover a small hole easy. Some humidity is inevitable, but these guys live where moss grows on the spokes. For the rest of us, a drip loop on the wiring is all we need. Mabye a spot of gutter sealant on the wires opening.

I am not sure I would worry about it in NM lucky dog.

dogman said:

It made sense to me, once a drop of water gets in, it would tend to stay in there.

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I just pointed a heat gun on the low setting at my motor for a few hours. About 6 inches away. It finally worked
after that. But I'd rather do that once in a while then drill a vent hole that could potentially let even more water.

I'm using my bike as regular transportation right now though, so I have to figure out a way to make it more
reliable in the wet. I see that Bafang has new motors advertised as waterproof. I might try one.

zukster said:

dogman said:

It made sense to me, once a drop of water gets in, it would tend to stay in there.

Click to expand...

I just pointed a heat gun on the low setting at my motor for a few hours. About 6 inches away. It finally worked
after that. But I'd rather do that once in a while then drill a vent hole that could potentially let even more water.

Click to expand...

Sounds like wet and shorted hall sensors to me and there is an easy fix. These cheap chinese hub motors always rust right to hell.
You park the bike in the fall and go to ride in the spring and the motors are usually frozen solid with rust!
Even if you ride daily year round like myself the motors build up with rust. It is totally impossibe to prevent moisture buildup in a hub motor regardless of the make and design by the simple fact that the heat cycling of use and storage draws in condensation from the outside air!
Thus the inevitable rust. Rusty water is an electrolite and this soon shorts out the poorly sealed hall sensors. To make matters worse, chrystalite mounts their hall sensors at the bottom of the stator and now they are swimming in this solution!
I've ridden 3 winters in a row in Ottawa Canada and I learned the hard way on the correct way to weatherproof a hub motor.
You need a product that is semi fluid so that it creeps and reapplys itself continuiosly to protect the metals from rusting and this includes the tiny hall sensors. So drilling a drain hole is out of the question as all of your protection would spray out as you rode. The water that gets in is not an issue, believe me!
The solution is so easy that you guys may at this...... Drill a hole mid-way on the radius of the hub cover the size of an aerosol can-straw.
If you've opened your hub, reapply sealant to the mating surfaces. Thats it!
Now get a water repellant lubricant such as silicone spray and fog your motor with it; the hole is great for periodic reaaplication.
My lube of choice is Wurth Film as it is extremely resistant to mixing with moisture and it won't wash off of it's applied surfaces.
I don't even cover the hole with anything, it's so small it's not worth worrying about.
Trust me, this works and your hub problems are gone for good!

Affliction said:

You park the bike in the fall and go to ride in the spring and the motors are usually frozen solid with rust!

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Were only talking six months in summer plus this winter so far, so I haven't actually opened it up yet
to check - but I shall. I greased the gears well with synthetic grease before putting it together in the
1st place. How does that Wurth Film silicone spray interact with grease? (if you know)

Thanks for posting your fix. Other people on the forum have discussed the idea of filling the hub
with some kind of oil or packing the whole thing with grease before putting it on the bike but I
don't think anyone tried it.

There was also concern about some of the oils or greases negativity effecting some of the mess
type stuff in the motor that keeps some of the wires in place in some motors.

Affliction said:

You need a product that is semi fluid so that it creeps and reapplys itself continuiosly to protect the metals from rusting and this includes the tiny hall sensors....Now get a water repellant lubricant such as silicone spray and fog your motor with it

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So what do you mean by "fog"? Don't you just have to use enough so you know its sloshing around?

My motor is a Banfag SWXH rear. What's yours?

I just read that Wurth Film is a silicone dielectric spray.

That gives me the idea of opening up my motor, packing it with silicone dielectric grease ,
the closing it up to lock it in. Its pretty cheap at Canadian Tire, or I wouldn't consider it.
7 dollars for a 85 gram tube of Permatex Dielectric Tune-Up grease, which I verified is
silicon based.

That should stay in there a while without needing to drill a hole at all.