Inside the Quark 125, pics.

[thesteve]

Originally Posted by GriffinRU

And this story about FET's and high voltage based on?
And do not blame fet's control if you not sure how it works...

Artur

Based on education and several years experience working with, repairing and designing speed controls that use mosfets. And anyone thats knows basic mosfet operation would also know...

[jhautz]

I'm looking at this thing trying to think of how to get more heat out of it. Adding additional mass to the bottom seems to make a huge differeance in disapating the heat. But thats only taking heat off of the bottom layer of fets. I'm thinking that opening this thing up and adding somethiing to the sides of the heat spreader to help pull the heat out of the middle of this thing could be the ultimate way to heatsink it.

Do the sides of the heats spreader contact the aluminum sides of the case?

This is really interesting to see how its set up inside. I have been wanting to tear mine open, but didnt want to void my warranty.

Cartwheels, If you open it again can you get some pictures of the top board also? Anyone know what part of this thing is the BEC?

[GriffinRU]

Originally Posted by thesteve

Based on education and several years experience working with, repairing and designing speed controls that use mosfets. And anyone thats knows basic mosfet operation would also know...

Well, then any good (Quark is good) pump-charge based (not fixed 12V) fet driver has a feedback, which helps to set the voltage at level which guaranties FET's turning on and FET's safety (not to exceed GS voltage) and as well fast transition and...
Based on this your previous guess is wrong!

And any comments on Leroy's question as a professional?

Artur

I have my Quark opened up again. I'm going to need to secure the Fets to the heatsink since the boards are just sloshing around inside the case. Here is a picture of the inside of the heatsink.

It has a piece of Aluminum secured with what looks like a heat pad. So it goes heatsink, heat pad, aluminum and then heat pad stuck to the Fet's. Maybe this is part of the cooling problem. If the Artic Alumina is better than a heat pad, I would probably remove the 2nd heat pad too. Are heat pads very efficent?

Here is also a view of the top of the boards. The heat spreader does not touch the heat sink.

[Serum]

depending. The thinner the layer, the better. as long as the contact area is optimal.

I would use thermal paste to hook the aluminum to the case and use a thermal pad to connect the fetts to the aluminum spacer.

Now you have got it open, can you please check the voltage on the caps?

On the caps unfortunatly, I can't find any markings other than: TDA . There is about 1/3 of the cap I can't see though. Is there another way to tell the voltage.

[Serum]

Remarkable..

[Mikey]

Originally Posted by Cartwheels

On the caps unfortunatly, I can't find any markings other than: TDA . There is about 1/3 of the cap I can't see though. Is there another way to tell the voltage.

sure you can keep uping the voltage untill it blows :027: j/k that wouldnt be good to do. the voltage is probably on the 1/3 you can't see.

[neweuser]

You could ask Mike what the voltage is, he MIGHT know. Or even, send Qaurk an email and ask....they would definately know.

Update: While I had my Quark apart I decided to go ahead and remove aluminum spacer between the heatsink and the fets. It was held on with a thermal pad. It was only half stuck on. You could tell that dust had gotten to the thermal pad. Half the pad was covered with dust and the other half was stuck on well.

My plan was to put it back together and substitute thermal epoxy for the heat pads. The epoxy is much thinner so I had to carve out some space for the caps in the heatsink otherwise they would prevent the fets and the heatsinks from fitting flush. I also had to trim some of the plastic under where the phase wires come out for the same reason. I've got it all back together and have not run it yet, but I expect it to run at least a little cooler. I had 3 fans on it before and it was still thermaling.

In conclusion, I think the thermal pads can contribute to some of the thermal problems with the Quark. The sticky part of those pads just can't hold up to the rough, hot, dusty environment and will fail eventually. Not to mention the heat has to transfer through 2 of those pads to get to the real heatsink!

The real test will come when I run it again. It my be a week or two before I can run it again.

[neweuser]

Very good. Let us Quark users know how it does. Thanks for all the info!

[smhertzog]

Originally Posted by Cartwheels

Update: While I had my Quark apart I decided to go ahead and remove aluminum spacer between the heatsink and the fets. It was held on with a thermal pad. It was only half stuck on. You could tell that dust had gotten to the thermal pad. Half the pad was covered with dust and the other half was stuck on well.

My plan was to put it back together and substitute thermal epoxy for the heat pads. The epoxy is much thinner so I had to carve out some space for the caps in the heatsink otherwise they would prevent the fets and the heatsinks from fitting flush. I also had to trim some of the plastic under where the phase wires come out for the same reason. I've got it all back together and have not run it yet, but I expect it to run at least a little cooler. I had 3 fans on it before and it was still thermaling.

In conclusion, I think the thermal pads can contribute to some of the thermal problems with the Quark. The sticky part of those pads just can't hold up to the rough, hot, dusty environment and will fail eventually. Not to mention the heat has to transfer through 2 of those pads to get to the real heatsink!

The real test will come when I run it again. It my be a week or two before I can run it again.

Have you tried it out yet?

Tomorrow, I'll be running it with no fans. I've got my fingers crossed.

[Serum]

Have you got a temp-gun?

I have a temp-gun. It's one of those small Dura Trax ones.

I did run the Quark today. My setup has changed from what it was. I'm now using a Neu 1515 1Y. Batteries are the same, 4s 7400mah lipo and gearing is 12/51. Before I was using a 540c 9L and I always had trouble with temps creeping up to 200*F and above towards the end of the run.

Look Mom No Fans!!!
Today went good with the Quark. It never thermaled on me even without fans. It does have a pretty good heatsink mounted on it with the front windshield completely cut out for air circulation. Temps stayed in the 125* range for a good portion of the run. It was pretty much all out non stop going for approx 20 min or more except for a couple of temp checks. Towards the end the temp did get up to about 147*, but it never thermaled. The motor was at 159* at the end. The outdoor temps were much cooler then a month ago when I started this thread. It was a nice 88* day.

One of the most notable things was the temps at the boards where the motor wires come out. In the past that area was generally 15-20* hotter than the heatsink. This time those temps were only 1-3* difference and they would even out within a minute or two. To me that was pretty significant. It tells me that the work I did may actually cool the internals better and more quickly.

Quark vs. Mamba
The Quark felt like it had a higher top speed. The Mamba felt like it need to go up a tooth. Punch seemed equal. Quark overall had a more powerful feel while the Mamba felt a littler smaller. Don't get me wrong though I love the Mamba, but for 1/8 if you can get the Quark not to thermal I think it is a little more suited.

In the end I think I may still have to run a fan on the ESC, but I'm going to push it and see what happens without a fan first.