Waterproofing electrical components

antboy

New Member
I've done some searching here, and looking at videos, but have a couple of questions about making my Spark Mini more water/snow resistant.

I'm not planning on doing heavy riding in such conditions, but the Mini is perfect for doing grocery runs, as the winter walk is about 25-30 minutes, but the ride is 5.

Specifically, the controller box sits behind the crankset and has a hole in the front and rear for cables.

The base of the seat tube battery locks in at the top of the controller box, and after a 50km ride this weekend that wasn't SUPPOSED to be as rainy as it was, there was a little moisture.

I'm considering something like silicone caulk or possibly some sort of durable tape like Flex Seal.

Any recommendations?
 
I have read these suggestions when I was wondering the same thing, but I cannot vouch for the suggestions. Ask others to confirm or de-recommend.
They say a good idea is
1. have the wires enter from the bottom
2. have a drip loop in the wire
3. have a drainage hole
4. put packs of water absorbent stuff inside the controller (I might have thought of that one myself)
5. paint the electronic board with proformal coating and make sure it's thoroughly dry everywhere it got to, before turning on the power (even some nail polish can be the coating). Nail polish coating worked GREAT for my toy drone that is susceptible to landing on wet grass and many people saw theirs get fried. After coating it I sank it under water a few times, pot of water on the stove, dog's bowl etc and nothing bad happened, just got it out real quick and turned it off and dried it out in front of a fan very well.
 
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BBassett

Active Member
I've done some searching here, and looking at videos, but have a couple of questions about making my Spark Mini more water/snow resistant...

Any recommendations?
Once I've sprayed the connectors with ACF-50 I bundle all the loose wiring and unused connectors into a small Dyeema bag just in front of the stem. Then ACF-50 is applied to everything but the brake rotors and pads, be careful of over-spray

ACF-50 - https://learchem.com/products/acf-50.html

Check out this video -

 

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sl_duck

Member
Here's a good video on waterproofing electronics for RC airplanes, mostly using anti-corrosive sprays and conformal coatings. Maybe some of that could be applied to your system, although I'd be careful with the heat that the controller can produce.
 

harryS

Well-Known Member
I have a bike with the same frame. Ecotric. Both I and another forum member have had water get inside the controller and stop the bike, but we both were able to clear the water.

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On other ebikes, I have the controller mounted over the tire, under the luggage rack. What I have done there is to run a bead of silicone around the seams of the end plates. You don't have to remove the plates. A glob of silicone where the wires enter the rubber gasket in front of the controller might help too. Those boxes are continually exposed to water spray, but after the above incident, I put on rear fenders.

It might help to repack the above controller so it doesn't sit on the floor too. There's not a lot of room, but maybe 1/8" spacer would be enough. There's a drain hole under the controller on my bike.
 

BBassett

Active Member

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antboy

New Member
Some additional great tips here.

The left side of the box has a removable panel, so it might be a good place for drainage as it slopes down to the back, and when the kickstand is up, the lower back becomes the lowest point.

I had read about ACF-50 before, and now I'm thinking it might be a good idea to go the whole 9 yards.
 

BBassett

Active Member
Beautiful. This saves me lots of work and some headaches trying stuff.
It's expensive, the 32 oz with a pump spray bottle is supposed to cover a surface using the least amount of product. I like to use both spray and actually paint it on, dab it on with a stiff bristle brush. Don't let a spray can fall onto its unprotected nozzle in the middle of your smooth garage floor or you will be skating around for a while.
 

Thomas Jaszewski

Well-Known Member
I’m a bit of a fan boy when it comes to ACF50. If it can protect avionics in a harsh environment, it’ll serve me well on eBike builds. Every connection on a dozen or more builds was treated and all connections have been virtually moisture free.
Another great reason to use a BaFang BBSXX. Water isn't much of a concern for the controller... ever.
black RTV, worked into every seam is incredibly effective. Especially into the rubber grommet where the wiring exits the motor. I stopped using gaskets and use liquid gasket instead of paper gaskets. Just be judicious on the volume used.
 

Thomas Jaszewski

Well-Known Member
My favorite sealant is JB Weld RTV. It’s extremely pliant, remains very “soft” when cured. Rather thin compared to many silicon sealants, and easy to work into seams and wiring exit ports. J-B Weld 31319 RTV Silicone Sealant and Adhesive - Black
 
I bought ACF-50 on Amazon and I'm buying the JB Weld Silicone at the hardware store today, so by next week I can have protection against a downpour.
Thanks for starting the thread, antboy. This issue was nagging me.
 

antboy

New Member
Just want to say thanks again everyone.

I bought ACF-50 on Amazon and I'm buying the JB Weld Silicone at the hardware store today, so by next week I can have protection against a downpour.
Thanks for starting the thread, antboy. This issue was nagging me.
I think that's the route I'm going to go, as well as seeing about raising the controller box up a little.

I've read that the Bafang thumb throttle/ C965 display and power button aren't the most water resistant either, so I'm going to try and get into any nooks and crannies there with the ACF-50, and maybe look for a better cover than Ziploc baggies and elastic bands. :)
 
No JB Weld silicone to be found in 5 locations I went to today. Home Hardware carries it but 3 stores didn't have it. I could have phoned them but it was another excuse to bike around. They're cheaper than Amazon and maybe quicker, so I'll order it in.
 
Do you know how to open up the C965 display in order to spray inside? I don't want to try too hard at prying the screen up.

Also, Home Hardware only took a few days to get the JB Weld silicone in.
 
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antboy

New Member
Nice. I got a tube of it from a friend who works on cars. Still waiting for my ACF-50 to come in.

As for the display, I'm not sure but it looks like there's 4 screws in the corner. This video had both the button set and the display opened up, but doesn't show disassembly.


I'm considering looking for some sort of jerry-rigged clear covers for the cockpit components that are easily removed, beyond the plastic baggies and elastic bands I used on my rainy ride.