Controller potting. Advice needed.

Pawel1976

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Is it good idea to use epoxy resin for controller potting for good waterproof and heat dissipation?
I found this epoxy, apparently one of the best on the market. What do you reckon.
Can I pour this substance into the controller, mosfets, capacitors etc ?

Epoxy Resin ER2221
Epoxy Resin ER2222
 

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Why make work for yourself that could get in the way of a required fix later on?

Unless your white water e-biking, whats the need? Your time would be better spent ensuring your motor is as watertight as you can get it and if its a hub drive that its not mounted upside down like so many are shipped from the factory..
 
Required fix later on?
No need for that, because the controllers are everywhere and cheap.
The motor is sealed all around, the screws checked etc.
What do you mean by, the hub is upside down?
 

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Grin fully epoxy pots their Phaserunner controllers. In their discussion of past models they mention this:

" In early 2019 we switched this design to using a stamped metal shell instead of a bare resin finish so that we could switch to a lower durometer potting resin that would put less thermal stress on the components. "

So if Grin's experience is meaningful, I'd be looking for a lower durometer epoxy or other low durometer potting compound. Note that they said "resin". That might very well refer to an epoxy. But it may not. I'm pretty sure the earlier models were potted with epoxy. There seem to be a lot of potting compounds available online with datasheets. All that said, potting the controller may be overkill and the epoxy isn't exactly cheap. Maybe just seal the box up really well and use some silicone seal at joints and mating surfaces.
 
I think by upside down he means the motor cable goes down then up into the hub, As opposed to going up then into to the hub. The idea is that the cable has a drip loop, and thus liquid water is channeled away from the motor.
 
Why make work for yourself that could get in the way of a required fix later on? ...
Grin fully epoxy pots their Phaserunner controllers. ...
Guess it depends if you think your controller is in greater danger by exposure to water/moisture/dirt/vibration, or you think there is a greater chance you could blow a mosfet or other component.

Maybe a good controller running well within established parameters with no chance of overvolt or overcurrent...better off to pot it. But if you're hot rodding a controller and pushing to within a fraction of the max ratings then ease of repair would be more critical.

Not to be critical of Grin, but of course they'd rather sell a whole new controller than have someone replace a 4 dollar mosfet. They also make quality components, so likely dirt/water/vibration is a bigger killer than overpower.
 
Not to be critical of Grin, but of course they'd rather sell a whole new controller than have someone replace a 4 dollar mosfet. They also make quality components, so likely dirt/water/vibration is a bigger killer than overpower.
It's far more likely that grin will replace the entire controller for free under warranty if you manage to blow a mosfet because it almost certainly means there was a manufacturing defect since the software doesn't let you go over safe limits. You're more on to it in the second part -- they want to make highly reliable parts they don't need to service, potting helps a lot in that vein.
Grin fully epoxy pots their Phaserunner controllers
I bet the OP could email grin, ask politely, and they'd tell them what epoxy/resin they use. It's not likely any big trade secret.
 
I bet the OP could email grin, ask politely, and they'd tell them what epoxy/resin they use. It's not likely any big trade secret.
That seems likely to me as well. Heck, for all I know @justin_le may have mentioned it online here somewhere.
 
It's far more likely that grin will replace the entire controller for free under warranty if you manage to blow a mosfet because it almost certainly means there was a manufacturing defect since the software doesn't let you go over safe limits. You're more on to it in the second part -- they want to make highly reliable parts they don't need to service, potting helps a lot in that vein.

I bet the OP could email grin, ask politely, and they'd tell them what epoxy/resin they use. It's not likely any big trade secret.
That seems likely to me as well. Heck, for all I know @justin_le may have mentioned it online here somewhere.
So I got curious and found this reply to exactly that question back in 2017. Interestingly, he did not actually answer the direct question.

"I wouldn't worry too much about electrical insulation, they're all pretty good in that regards unless you are talking something with metal filler (or perhaps you are still dealing with 700+ volts?!). In the end what became the driving priority for our resin selection was very low mixed viscosity so that we could fill the phaserunner molds without air entrapment, and a reasonably low cured hardness spec so that the epoxy wouldn't be brittle in cold weather or stress the internal electronics too much. Thermal conductivity wasn't much of a concern since all the heat flow from the FETs is directly through the aluminum heatsink that is directly exposed to outside air and making physical contact to the metal bike frame."

 
Grin fully epoxy pots their Phaserunner controllers. In their discussion of past models they mention this:

" In early 2019 we switched this design to using a stamped metal shell instead of a bare resin finish so that we could switch to a lower durometer potting resin that would put less thermal stress on the components. "

So if Grin's experience is meaningful, I'd be looking for a lower durometer epoxy or other low durometer potting compound. Note that they said "resin". That might very well refer to an epoxy. But it may not. I'm pretty sure the earlier models were potted with epoxy. There seem to be a lot of potting compounds available online with datasheets. All that said, potting the controller may be overkill and the epoxy isn't exactly cheap. Maybe just seal the box up really well and use some silicone seal at joints and mating surfaces.
Ok. Yes, thanks for that update. Its very important. Im thinking more about overheating than waterproofing.
 
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