Quark 125B works, but stops after 3 minutes...
 

I installed the Quark in my e-maxx today, to only find it would do 2 laps on the track before it would thermal, I was running 5S, so I tried 4S and I got another lap extra, I was not happy.

Now, I do have the heat sink from rc-monster. I have a few questions to see if I can fix this problem:

1. Do I use the heat sink on the top or bottom? I have it on the bottom (with the ESC on its side), so I could have access to the program button.

2. Should I lay it flat on my FLM chassis? With the button side down, and the heat sink on the bottom face up? What is the best way to install it so that it will run cooler?

3. I set Li-Poly High, and I'm running MaxAmps 5S 8000. Should I try Li-Poly Normal?

4. Should I cut out holes in the body? I haven't done this yet, to keep it clean inside. But, with it the way it is now, I can't even run it for 3 minutes with it stopping.

More info:
Around 9lbs with no batteries
Castles BEC
3 fans, 1 for motor and 2 for ESC, using rc-monsters heat sink
I wire the fans directly to the batteries
9xl
Strobe Spur 51/14

Any other ideas, is greatly appreciated!!

Sounds like gearing might be off. Try changing the gearing up. I think the Quark mod might be in order. There not exactly the best when it comes to dealing with heat.

When you say "gear up", do you mean a higher tooth pinion? Wouldn't that make it run hotter?

here is a pic of how i have mine mounted, and it runs perfect all the time, and i have yet to do the quark mod.....
http://img.photobucket.com/albums/v4...s/DSCF0297.jpg

I might have another problem then, 3 minutes seems very quick. I plan to call support to see what they think...

How do you mount this to the chassis?

The internal mod may or may not be needed. It depends on how long the thermal pad holds up. After a while the adhesive bond weakena and the ESC will seperate from the case. When that happens, the FETs aren't contacting anything so they overheat MUCH quicker.

Some of those thermal pads hold up ok for longer time than others. So, just because some people still have no heat issues doesn't necessarily mean you won't.

One way to tell if temps are the issue is to feel the ESC case and then the PCB at the motor wires. If the case is cool or just warm, but the wires are hot, then the FETs aren't making good contact. I've modded both my Quarks and have yet to have any trouble with heat.

I ran my 5s on a 9xl with my Quark geared 51/14 with 1/8th diffs with no problems. But I found the 16T pinion was a bit better. If you are not running 1/8th diffs, 51/14 should be fine. I ran the 51/14 on a 10xl for months with no issues.
I would mount your esc like sjcrss has his. It should be fine.

Here is how I have mine.

[QUOTE=BrianG;125828]The internal mod may or may not be needed. It depends on how long the thermal pad holds up. QUOTE]


I don't even have a thermal pad, where would I get one, computer store?

I will also check the wires, good tip. I almost remember thinking the wires were hot.

You have no thermal pad on the inside of the esc? If not, send it back!
Also, it's typical for the wires to be somewhat warm on the back of the esc that go to the motor. Sometimes, mine are to hot to touch for a long time, but not too bad.

sorry, I thought you meant thermal pad for the RCM heat sink. Do I need one for that?

Not for the heatsink. You will want to mount the esc with some thermal (ArcticSilver) paste. So spread some on the bottom of the esc, stick the heatsink on, make sure you have clean contact that is nice and even, clean the edges. Then you zip tie it. I think sjcrss used white paste for PC's, which is not the best to use, but it does work. I used arctic silver.

wether the thermal pads hold up or not greatly depend on how round the powerboard of the quark is. I started a thread about this, you can see what i am trying to explain.

Where?

http://www.rc-monster.com/tempforum/...read.php?t=379

right here.. :)

Sorry, been gone awhile again. Hehe. Thanks!

I have yet to need to do this though.

Newe is right, i originally used the white adhesive, but have since switched it over to the Arctic silver 5 compound, and to mount it to my chassis, I had Mike drill and tap to holes on the side of the rcm quark heatsink, and then i drilled 2 holes in the back ext. plate and bolted it to the plate, i also used a little compound between these to joints as well, it couldn't hurt, then i just mounted up the quark like new said....

If you are considering doing the Quark "mod" be aware that this will likely void your warranty and prohibit any on the house out of warranty repairs.

I just recently got back a Quark that I had to send to S&T. It had a note from Frank attached to it and it said that I should send it back in again, if the thermal pad comes loose again, because they won't be honoring the warranty on any Quarks that have had the cooling modification done.

:gasp: that is a good thing to know, Im glad that i havn't had to do this mod yet.....thanks for the info....

Yeah, warranty claims may be difficult, but the mod really helps speed the transfer of heat from the FETs to the heatsink. As long as you are careful completing the mod and use the ESC within specified limits, there should be no problems. :smile:

I may have found the problem, I had the mgm 16018 and had thought it died, well, after emailing them about it I found out that my min value was too high (can't be higher then 1.2ms). I'm now thinking that maybe that was causing my truck to stop after 1 lap, in fact, the 16018 was doing the same thing, then I tried to reprogram it to no avail.

I'm looking for suggestions on which radio I should get, I hear the specktrum is good.

That is a god choice, I run the JR Xs3 radio, and have had zero issues, and it is very adjustable...

I only mentioned the warranty issue because they (S&T) had warrantied my Quarks with the mods on them. They are saying that they won't any longer. I wonder if they think that it's the same controller that I keep sending them.