Ebike controller overheating

Pawel1976

100 mW
Joined
Sep 3, 2024
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Blade197600
Hello everyone

How to prevent my ebike controller from getting too hot?
Is it possible to fill inside with any cooling liquid/substance?
Do you think, that Thermal Conductive Potting Adhesive: People commonly use thermal conductive potting adhesive for potting electronic components. It enhances heat dissipation and provides mechanical protection. It offers high thermal conductivity, heat resistance, sealing, and mechanical strength. This adhesive protects electronic components from the environment. It is good for use in power supplies, batteries, transformers, and inductors.

Thank you.
 

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How about bolting it on to solid metal somewhere on the bike with good airflow?
Yes, I know that my friend. It could be the best idea but, in UK and exactly in the town where I live the cops are not very friendly. Its not good idea where the controller and all the wires are hanging around. Prefer to hide as much as possible, no eye catching.
 

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It looks like the thermal management for that "bike" is as well designed as everything else about it.

My advice is to use a bike that doesn't have an inside to hide necessary components in.
 
If there’s nowhere for the heat to go, then use less throttle.
Recently I shuffled the e-conversion parts for my two wheel drive bike over to a new frame because the old one had cracked. Because I didn't want to take up a pannier spot to tie on the controllers (which is what I had done before), I temporarily lashed them to the seat tube and seat stays. The 30A sensorless controller I use for the rear wheel makes contact with my leg when it's in certain parts of the pedal stroke. I've noticed that it seems to warm up more when I'm using partial throttle.

It doesn't get nearly warm enough to be of any concern at all, but it does make me wonder why it feels like it's discharging more heat when I'm not running WOT. It could be as simple as its air cooling being disproportionately effective at full-blast road speeds, but it feels like more than that.

Anyway this is the first dedicated sensorless controller I've used on one of my own bikes, so I'm unsure whether it's a quirk of sensorless operation or something else.
 
Recently I shuffled the e-conversion parts for my two wheel drive bike over to a new frame because the old one had cracked. Because I didn't want to take up a pannier spot to tie on the controllers (which is what I had done before), I temporarily lashed them to the seat tube and seat stays. The 30A sensorless controller I use for the rear wheel makes contact with my leg when it's in certain parts of the pedal stroke. I've noticed that it seems to warm up more when I'm using partial throttle.

It doesn't get nearly warm enough to be of any concern at all, but it does make me wonder why it feels like it's discharging more heat when I'm not running WOT. It could be as simple as its air cooling being disproportionately effective at full-blast road speeds, but it feels like more than that.

Anyway this is the first dedicated sensorless controller I've used on one of my own bikes, so I'm unsure whether it's a quirk of sensorless operation or something else.
My thought is that the sensorless controller is more efficient at higher speeds (not as efficient at lower). Due to how a sensorless design works using back emf to determine rotor position, it automatically adjusts timing which results in higher efficiency than using the halls. I don’t have a phaserunner, but I believe I’ve read that it starts out in sensored mode, but switches to sensorless at higher speeds, so the best of both worlds.
 
Could be an airflow difference too. Supposedly the air stream next to the legs is quite turbulent. I almost bought a Sava carbon acoustic folding bike the other day, hated the airplane wing shaped seat tube, and even the salesman admitted there's not much point to streamlining there.
 
Yes, I know that my friend. It could be the best idea but, in UK and exactly in the town where I live the cops are not very friendly. Its not good idea where the controller and all the wires are hanging around. Prefer to hide as much as possible, no eye catching.
Maybe forced air ventilation then? Stick a little 5V computer fan on either end? Or buy a controller with more MOSFETs in parallel to distribute the load.
 
It looks like the thermal management for that "bike" is as well designed as everything else about it.

My advice is to use a bike that doesn't have an inside to hide necessary components in.
This controller is on the rack, behind the seat, you can zoom it. Inside the frame is one battery and some wires only
 
This controller is on the rack, behind the seat, you can zoom it. Inside the frame is one battery and some wires only

Well if the controller is getting hot, then either it has too much surface sheltered from ambient air flow, or it's a crappy controller. Either problem is simple to fix.
 
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