Which side of ESC to mount against model?

[Mitchell Howard]

I have a ZTW Beatles 80A - There's a smooth side with the branding on, and there's a bumpy side with components under the shrinkwrap.

 

Which side would you apply the Velcro to?

[Don Fry]

The smooth bit is the heat sink. Leave exposed to the air.

[Simon Chaddock]

Agreed but my issue with most ESC is the smooth side is a heat sink rather than a heat radiator as it is covered with shrink wrap which is a pretty good insulator. 

Of course the wrap gets warm so will transfer some heat to an external air stream but the heat transfer rate is low which makes the airflow all the more important.

 

If only proper 'finned' heat sinks were put on ESCs (other than the biggest and most expensive) then cooling ESCs would be much easier and more effective.

 

 

[Don Fry]

I half agree, but accept the maker has some competence. That’s what is judged best, or good enough, by the maker. And I think the sink bit is a bit of weight that cools lighter bits underneath, or at least keeps the solder solid. Said lighter bits are critical.

Anyone care to try a test, heat sink inside or out.
Load it with a big prop, aim at the moon, and keep going. If it survives, bigger prop…….

What side fails first.

[Peter Beeney]

Perhaps a slightly alternative way of installing the ESC would be to cut away a piece of the shrink wrap over the heat sink, slightly smaller so that wrap is still held in place around the edges; and then painting the exposed ally with a coat of matt black paint if you have any. Then make sure it’s fully held in the mainstream flow of cooling air. This might be helped by strategically placing baffles to make the cool air flow close to the ESC as opposed to flowing around it. Rather in the manner that similar baffles are placed the cowl of a an i/c engine to make the air flow through the fins rather than around.

 

I don’t think I’ve ever even considered sticking the ESC to anything; seems a little too close to temping providence for me. I’d have thought they generally need all the help they can get to keep that lump on the front in constant good circulation….

 

Just a thought…

 

PB

 

[Andy Gates]

I have a 75" Chipmunk which flies at 1/2 throttle most of the time which means the switching in the ESC is working quite hard so that it gets hot.

 

I fixed an old computer CPU heatsink to the ESC and it is much cooler and way less stressed. It has been flying this way since 2006 still with original ESC & motor combination, the motor is on its 2nd set of bearings though.

[Ace]

I have made "C" shaped plastic holders from various sizes of plastic channel which hold the edges tacked in with dabs of hot melt glue, exposing both sides to the air flow.

Anyone considered/able to  design a 3D printed version similar to a spring clip which would be scalable?   

Edited June 12, 2021 by Ace

[Chris Bates]

If You have room, My setup for my Twin.

[MattyB]

18 hours ago, Simon Chaddock said:

Agreed but my issue with most ESC is the smooth side is a heat sink rather than a heat radiator as it is covered with shrink wrap which is a pretty good insulator. 

Of course the wrap gets warm so will transfer some heat to an external air stream but the heat transfer rate is low which makes the airflow all the more important.

 

If only proper 'finned' heat sinks were put on ESCs (other than the biggest and most expensive) then cooling ESCs would be much easier and more effective.

I sort of agree, but in reality shrink wrapped ESCs work absolutely fine in all but the most demanding use cases (i.e. high current and low airflow). If you are worried just cut off the shrink wrap over the heat sink and add some additional metalwork(!), but it should not be necessary in the vast majority of cases unless you just cannot get adequate airflow through the fuselage.

Edited June 12, 2021 by MattyB

[Simon Chaddock]

The fact that the limited natural airflow in RC ground vehicles requires 'cooled' ESCs does rather suggest that an efficient cooling arrangement is advisable for reliable aircraft operation.

Adding additional metalwork, actually a 'fingered' heatsink, is exactly what I do, particularly in a high powered application.

It has at least 10 times the heat transfer per degree compared to a shrink wrapped aluminium plate.

Over kill it maybe but it virtually eliminates the possibility of the ESC overheating.

It works for me. 

 

 

[Steven S]

Heat sinks are available on line, I have bought a couple from robot supply stores

[Martin McIntosh]

Some TGY escs have a large exposed sink on one side making it tricky to adhere Velcro to the other. Another case of non modellers designing things. However, I do not generally pay much attention to cooling them, the motor is much more important. As long as they are way over rated for the application they should be fine. My Lancaster has them mounted inside the fus so that I do not need to extend the battery leads. The only cooling is what leaks through the bomb doors and whilst they get hot, not overly so.

[Mike Blandford]

In my opinion the main requirement is some airflow over the ESC, however it is mounted. I have a FrSky Neuron in a large, aerobatic model, running from a 4S, 6000 lipo.

This supplies up to 60A. Since the Neuron sends lots of telemetry, I have logfiles showing the temperature of the ESC. Early flights, with limited airflow, show the temperature reaching over 80 degrees C.

I then added a small air scoop on the side of the model, inlet size about half an inch square, there is already plenty of air exit space. The result is the ESC only goes above 30 degrees C after the flight when there is no real airflow.

 

Mike

[leccyflyer]

Mike's right - airflow over the esc is crucial where the esc is working hard. On some of my models I've added airscoops and even internal tubes to feed airflow over the esc. Don't forget the exit hole for this airflow is supposed to be larger than the intake  the theory being that the warm air has expanded. I'm not sure how valid that is, but do try to put a vent hole somewhere for the airflow to escape.

 

It's not always needed though - some models seem to do fine absolutely stock with no modification - even foamies where the esc is stuck to the fuselage.

[David Hall 9]

Modern switching devices have become very efficient.  There are 70A BLHELI_32 ESCs  (without BEC)  installed in some of my e-gliders that have no heatsinks. They are pushed to 50A working for 30 secs, then very little.  They don't even get warm.     I think that the heatsink is as much for the BEC, particularly linear BECs.   

[Philip Lewis 3]

To answer the original question, as someone who has experienced an ESC fire the answer is neither (especially in a moulded plane), just suspend it off a couple of carbon rods across the fuselage (if you have enough room).

[Ron Gray]

Be very careful with carbon rods and leccy stuff!

[john davidson 1]

well instead of carbon use BBQ bamboo skewers, cheap as chips!

[Andy Gates]

This is what I have just done to my ZTW Beatles 60A which does not have much cooling and got a little too warm for my liking over the weekend.

 

I used a heat gun on the label to soften the glue, removed the label and stuck it on the other side, then cut a hole in the heatshrink and attached a heaksink to the metal plate with thermally conductive tape.

[Keith Berriman]

Hi Andy 

Just of topic  but interesting ESC to Battery connections  I also use this configeration not seen it on any other members flying electric models at my club 

[Andy Gates]

I standardised in using those terminals early in my electric flying because I use batteries in multiple configurations.

 

In this instance it is a single pack to a single motor, but I also use double packs in parallel to a single motor and double packs in parallel to twin motors.

If I ever wanted 6S I could use 2 x 3s packs in series.

This gives me plenty of flexibility in configuration without rewiring packs.

Edited June 14, 2021 by Andy Gates

[Mitchell Howard]

20 hours ago, Andy Gates said:

I standardised in using those terminals early in my electric flying because I use batteries in multiple configurations.

 

In this instance it is a single pack to a single motor, but I also use double packs in parallel to a single motor and double packs in parallel to twin motors.

If I ever wanted 6S I could use 2 x 3s packs in series.

This gives me plenty of flexibility in configuration without rewiring packs.

 

I like that Andy, but I figured it was frowned upon - no real reason, other than not having the + and - of a LiPo physically held apart by a connector.

 

If I was going to do that, I'd use 5mm bullets and probably double-shrink the LiPo females with a third partially unshrunk shroud left to prevent any unintended contact.

 

I like the EC5s I use because I know they're overkill and overkill is safe, but Christ are they a PITA to pull out.

Edited June 15, 2021 by Mitchell Howard

[Andy Gates]

I suspect my + & - are further apart than most connectors.

 

When not in use the - pin (the male one on the battery) I cover with a bit of fuel tube to ensure isolation in storage / transit.

I would ignore the frowners unless they can put up an incredibly good reason not to do it.

 

You will always have someone say X is better than Y and that the newest thing is the best, I have been using this system since 2004 and as yet I can't find a good reason to discontinue its use.

 

I always found Deans a pain to disconnect, likewise with the XT series.

I am an all year round flier so being able to disconnect batteries in the freezing cold is a must.

At least with the pins I can disconnect each wire holding the connectors in each hand. Can't say I can do that with the multi pin jobs.

[Dickw]

I agree with all of that Andy for all of the same reasons. The only difference is that I have been operating like that since the late 1980s.

I use 4mm bullets on most models, but 6mm on high current applications.

 

Dick

[Martin Harris - Moderator]

I used that configuration in the NiXX era and early days of LiPos before moving to Deans which I've used since.  What I did was put a piece of heat shrink over both conductors near the connectors so it was almost impossible to connect them together. Yes, I've witnessed a clubmate managing to connect both battery terminals together in the confines of a fuselage and it was spectacular to say the least!