weatherproof ebike

[davec]

i have been brainstorming about building a new ebike for riding in the rain
i know this topic has been discussed before however i figured i'd share my solution

this issue has been discussed
https://endless-sphere.com/forums/viewtopic.php?f=30&t=34135
https://www.youtube.com/watch?v=gwlbAJLzI_w

in short - the hub motor is a pressure vessel- heat generates pressure outwards and cooling creates a pull effect sucking in moisture/water etc

the solution is to either create a perfectly sealed hub or cut holes into the cover to eliminate this pressure-
At first i entertained the idea of creating a perfect compression vessel like a keg-
i speculated there are 4 places of entry into a hub which are cable, bearing seal, outer rubber seal, outer edges of side covers, gap in the axle between the wire and sheath.

on my first experiment to figure out where the weakest link was i sealed a hub motor completely at the cover seals with rubber silicon glue- put a co2 line on the hole of the axle- dropped it in a bucket of water to find out that the gas bubbles were leaking from the bearing/rubber seal- go figure. so the rubber seal is useless( they are water resistance not water proof) , and bearing seals were never meant to be a barrier. I suppose if one could replace the weak rubber seals with O-ring and fabricate a metal piece to hold it in place this would provide a good vacuum with the cable being the only way for pressure to get in and out. But the cable can also be solved by using epoxy in the axle- and putting in solid stranded wires covered in adhesive lined shrink tube to eliminate any flow through the power cables altogether - creating a perfectly sealed hub.
However i don't believe this is the solution- the pressure will eventually break down the seals.. bionx implemented this solution and i've seen their hubs rust out

the real solution is to eliminate the pressure at the hub level - doing so also stops sucking and pressure through power cables which will eventually corrode it unless those cables were sealed like i described above. But even if the axle was not sealed theoretically there should not be any pressure going through those cables if the pressure is eliminated on the hub level.

creating holes in the covers presents some drawbacks such as dirt/debris getting into the hub and not being able to store the bike outdoors.
but instead of just cutting large holes in , the better solution is to use gore vents- or even better cut the holes into the cover - order some gore fabric and glue it on the outside of the holes. This seems to be a good solution as the fabric allows moisture to depart, blocks water, moisture, and dirt from getting in and eliminates the pressure problem. You also get a nice window to allow the motor to run cooler.

so ultimately installing a better rubber seal, blocking the axle (heat shrink tubing on the axle where the solid wire leaves axle), and holes in cover with gore vents offers a good solution to riding in the rain.

note; also coating the insides is a must

http://www.gore.com/en_xx/products/venting/protective/protective_vents_why_vent.html
leaving the holes bare is possible - however for those concerned can drill a hole and use the adhesive vent
http://www.gore.com/en_xx/products/venting/protective/protective_vents_product_comparison.html

http://www.hitechseals.com/products/oil-seals-SL-met.asp?lang=
http://www.skf.com/pk/products/seals/industrial-seals/power-transmission-seals/radial-shaft-seals/index.html
http://www.tokez.com/en/industrialseals.html

 

[davec]

inexpensive ways to keep wires dry



http://www.littlegreenhouse.com/accessory/electrical.shtml
http://www.downwindmarine.com/Hubbell-Weatherproof-Seal-Tite-Covers-50A-p-91001950.html

stuffing the connector end points from controller/battery into the closure provides a cheap solution

another idea - to keep controllers water proof
cut a bicycle tube - stuff the controller inside- seal one end with rubber cement glue
on the other end have a cork/ or plastic block- drill hole through it, run wires through and glue to the other end of the tube

cover the throttle- with a bag or pouch
make sure all wiring is non-exposed- all wires in sheath- or covered with heat-shrink wrap- exposed wiring should be in the casing above

 

[motomech]

This is the MXUS "water resistant" kit that expands the use of the common 9-pin style connector. Many new kits are coming this way these days.
http://www.mxusebikekit.com/shop_show.asp?cid=46
As far as water in the hub, I really only worry if the water is so high it reaches the axle.
On the rare occasions this has happened to me, I just made sure it didn't "put the bike up wet".
In other words, I rode long enough in a dry condition that the normal operating temp dried out the motor.
It could even be the next day.

 

[davec]

i checked it out - looks like they beefed up the controller and wires with rubber seals- not bad but from the pics i cant tell how the hub is water proof

"As far as water in the hub, I really only worry if the water is so high it reaches the axle."

that's a different animal altogether - the goal is to be water resistant- unless your riding in a lake - even in downpour rain the puddle would never make it that high- i've seen a hub motor run underwater before, but riding through a pond or lake is not something i would ever be doing. you'd def be filling your hub up with water unless you had that perfect seal- even the gore barrier is rain droplet proof but not water proof so water would leak. with a sensorless this wouldn't be a problem and if you had the vents you could dump the water out if it filled up- but for something semi sealed you'd have trouble as water would be trapped in it for a while. most on here in dry climates don't have to worry, even light rain riding is fine- and stored inside should dry off-
for light humid climates you may get a bit of rust inside but you're probably looking at a new motor anyway by the time it rusts out

 

[motomech]

.... unless your riding in a lake - even in downpour rain the puddle would never make it that high...

Gee, thanks for telling me it can't happen. Next time I get caught in a tropical downpour in Matzalan Mexico and the streets turn into rivers I'll know I'm just hallucinating

most on here in dry climates don't have to worry, even light rain riding is fine- and stored inside should dry off-
for light humid climates you may get a bit of rust inside but you're probably looking at a new motor anyway by the time it rusts out

So you get a lot of "rusted out" motors do you?
Where do you live to you are so worried about moisture in the hub?
Why don't you just add a small amount of oil.
Maybe you should fill out your profile so we don't have to ask where you live.

 

[Alan B]

Seems like the most successful systems for keeping dry block rain and splash but are open to the air for drying out. Sealed stuff always fails, or has to be periodically opened up and dried out.

 

[davec]

..Gee, thanks for telling me it can't happen. Next time I get caught in a tropical downpour in Matzalan Mexico and the streets turn into rivers I'll know I'm just hallucinating

haha really-
that is something to experience- at least here i've never seen anything like that
that is one day to stay home....haha but you're right i shouldn't assume it can't happen

So you get a lot of "rusted out" motors do you?
Where do you live to you are so worried about moisture in the hub?
Why don't you just add a small amount of oil.
Maybe you should fill out your profile so we don't have to ask where you live.

im up north-east coast close to maine- i've had a hub go just from moisture and actually seized and became worthless (i never even used it in the rain)
i've had another hub blow hall sensors by moisture getting in and shorting them out
the point is for me an ebike is like a car- i need it reliable and i need it to last- without treating a hub you'll eventually run into issues in wet moist climates
oil works - but too messy for me - i like to keep it simple
you're in AZ- with a large amount of sunny days- you're pretty fortunate

Seems like the most successful systems for keeping dry block rain and splash but are open to the air for drying out. Sealed stuff always fails, or has to be periodically opened up and dried out.

yeah exactly