Fans for active controller cooling

[ccihon]

I have a KT controller mounted in a rigid tailbox on my trike - its mounted to the hinged lid. I have added holes front and back of the box to encourage air flow, but do not have a good way to run the controller out in the open - need to keep it dry, and keep the wiring harness tidy.

So far, on light rides the controller stays cool - just feels warm to the touch - but now out temps are approaching 100 degrees F, and I've noticed If I push the bike hard, the thing does get hot.

First question - how concerned should I be? I assume these things can take some heat. Maybe the main issue might be heating up enough to deform the plastic lid I have it mounted to - it has never come close to that.

Second question - would it make sense to add a fan to intake cool air - exhaust hole already there. If so, I could choose to add 5v unit and drive off the 5v throttle feed? Or, use 48v fans - or, buck converter down to 12v? I can switch control these for when I prefer the fan off - or even introduce speed control, I suppose. Main thing is to add some airflow, but not create a noisy buzz-box.

Some pics illustrate the current set - up. Battery is mounted low, just the controller is in the box, leaving room for some storage. I have added holes forward and back of the controller for airflow since taking these pics.

 

[DogDipstick]

I have begun incorporating 120mm 12v fans ( computer fans) into my batteries. The mounting template is available at Digikey for a million finger guard for 120mm fans.

Yes the controller gets hot, gets hot first too. I mount in airstream on front of bike.

Relative to the power output, hz cycles of operation, and the motor in question, yes it may get hot.
Do not choose a 5v fan, off the TH lead.. not enuf power int eh 5v rail circuit to support a fan. Fan needs like 0.3-1A.

0-5v circuit may provide 0.1A

A 12 is convenient cause lots of 12v DC-DC converter exist inthe range weneed.

 

[ccihon]

Thanks for the info - I had not taken into account the limited power available from the 5v rail - and the 12v buck makes sense as I can get a smaller one (~5A) for this purpose, and also add lighting etc - and I have some quiet PC fans already. Does it make sense to switch the supply to the 12v stepdown convertor? That would also shut down the fan, though I could switch it separately.

The 48v fans I have seen are for industrial or server rack-mount applications, so while some may be heavy duty, I am guessing they are also noisy.

 

[pwd]

FYI, you can easily find 48V etc... fans on Aliexpress. I'm using a small one on my bike to blow on the hub-sinks.

It would be better if the controller was in open air, that is what they are made for except for the fact the the cable harness isn't weatherproof. You can always add some silicone or liquid electrical tape to prevent water ingress.

 

[LewTwo]

It would be better if the controller was in open air, that is what they are made for except for the fact the the cable harness isn't weatherproof. You can always add some silicone or liquid electrical tape to prevent water ingress.

You mean like this ?

 

[Cowardlyduck]

You should check out this old thread:
https://endless-sphere.com/forums/viewtopic.php?f=3&t=70823&start=25#p1193558
It works, and I did it for a while, but the noise was annoying.



Cheers

 

[Jonno]

FYI

I used to use this Temp controller with a 12v computer fan as you can pre set the on/off temps- it works well

https://www.ebay.co.uk/itm/284358450378?hash=item4235159cca:g:~u0AAOSwxElg4QwW

Now I use a PWM fan as the Nucular controllers support them - much better way to do it

Jonno

 

[ccihon]

Thanks all for the suggestions - I mounted a quiet 92mm (3.5in) fan in the forward portion of the tailbox, blowing inward and out through the exhaust holes. It is driven by a small dc-dc convertor that I can also use for additional 12v accessories.

One question - I have switch the convertor ahead of the 52v supply, and I generally leave the battery for the trike connected except when charging. If I were to switch the 12v side individually, and leave the convertor unswitched from the high side, would it still have a residual draw current on the battery even with the 12v side accessories switched off?

I have been unable to source panel-mount rocker switches with led indicators on them that can work at 52V - well, the switch works fine, but the indicator light blow. Current plan is to just switch the dc-dc convertor and put a simple 12v indicator lamp on the 12v side. The fan is silent enough I feel I will forget and leave it on after a ride - I also think I can leave it turned off when the weather is cooler.