Quark 125b post thermal behavior
 

I'm still trying out gearing on my BPP LSP. With the Neu 1515 1y, 16/51 gearing and 4s2p 8000mah maxxamps packs...she thermals after about 1 minute of running. If I let her cool for about 1 minute...and then turn the epa down to 60% I can run her for another 5-6 minutes continuous, but she will often cut out. If I tap the brakes after she has stopped, she can go forward again. Is this normal behavior once the quark has thermaled?

Well, when i had my brushless lsp, i ran a 9xl with 16 cells on the Quark 125 geared 15/51 and NEVER EVER thermaled the controler. This is running for about an hour, under race conditions, in 85F+ weather too.....

Also, try and reprogram your controler.

Come to think of it, i have never had the Quark over 140F.............



Hope this helps.......

Bye :018:

*EDIT* BTW i am running heat sinks on my Quark..............

You're a very lucky man I and others on this board have not had quite as good of luck. Check this out:
http://www.rc-monster.com/forum/showthread.php?t=3405

http://www.rc-monster.com/forum/showthread.php?t=3861


natrix you're not the only one, but a a heat sink, case modifacations, and or fans will all help. I,ve been running my Quark with the modified (removed) case that you'll see in the second thread I listed above. I have tried to overheat it by overgeraring it and running lipo pack after lipo pack with no cool downs and heated up my 7xl but the quark has never thermaled. Mike also sells a heatsink in the brushless section of the shop.

You might be overgeared if you are thermaling that quickly. I would try some smaller pinions first. Even if you put heatsinks and fans I think you will still overheat with that kind of gearing. In my hyper 7 I run 12/51 on 4s and it is perfect. So you might want to start with lower gears and go up from there if there is no problems.

I kinda knew I was overgeared but I wanted to try and push it as far as possible with gearing. I'm going down to 13T on the pinion to see if I still get the cutting out/reverse to re-enable effect.

well for one the 1515 1y is a lot hotter motor than a 9xl. To get the same temps would need to gear lower than 9xl.

16/51 with a 2200kv is overgeared for all but speed runs imo.

I don't gear that tall even with my 1700kv 1515.... I think I would be running about a 12T pinion with your setup.

Still... maybe you have an esc issue, like the fets not getting good contact with the case.

I have this same problem. I'm going down to 4s instead of 5s. and changing from the 10xl, 9xl to the neu 1515 1/y. I was hoping this would change things. From this thread, it does not sound like it. ARGGGGGGG
What is up with these Quarks? I'll say it's the last one I buy!

And I don't think 16/51 is over geared for an emaxx at all. 18/51 or 20/51 maybe, but not 16T.

what pinion would you suggest Leroy? The Neu should be a cooler motor than the 9xl do to it's efficiency?

My wattmeter showed a 100 watt difference between the neu 1y and the feigao 7XL at WOT. Both motors never got very hot with 16/51 gearing. I'll post some numbers when I run my new setup tonight. I'm going to try 14, then 13T pinion. I epoxied new heatsinks to the quark and twin novak 25mm fans to cool them off.

Is this a truggy correct? That's what I was basing the gearing for...

After a quick run today, I saw a spark coming off the ESC wires on the quark. Very shortly after, the ESC stopped working. I let it cool down but now it has a really bad hesistation from a standstill, and it smells like something has been burnt near the wires. I think I may have toasted my quark. @#$%!

BURNT TO A CRSIP! Bad luck man. Loosing a esc is like losing a part of your heart. You'll probbably lose a kidney too, cuz u'll need to sell them to buy another esc!

I have to wonder why this happened. What caused the spark? If I plug her in she runs intermittently and only at a slow speed. The wires leading to the motor also start to warm up. Is this something I can fix on my own or should I send her in?

Perfect timing too, the last race of the season is this Saturday.

I tried reprogramming the quark in case it was a programming issue. It is still cogging ocassionaly but still works. Wierd. After this weekend I am sending it in to see if their techs can get rid of the cogging.

Quark has an extremely good customer service policy call them the'll tell you to ship it to them and the'll ship you a new one.:018:

I think maybe there should be a sticky for FAQ's on the Quark!

You going to run a slipperential. The one above is with a truggy. Alot taller gearing that you have with the slipperential.

I agree! Topics addressed should be adding heatsink(s)/fan(s) and how it doesn't "like" 6s even though it says it can. Maybe add the address/phone number, email address of S&T. After all, it's rated for 6s; maybe the newer models have a firmware revision?

I ran it today with my wattmeter attached and it was only drawing 700 watts, when it used to draw a little over 1700. I put a call in to Quark and they said to send it in. Their customer service seems to be very friendly.

Unfortunately if it is found to be defective, I will lose my freshly epoxied heatsinks. But that means I can pick up the newly designed one in Mikes store. :005:

The Mamba Max thermals at 225 while the Quark Thermals at 170 is it just a matter of thermal cut off temp?:032: :032: :032: 55 deg. is a big difference.

It's weird. I originally bought this controller to rid heat issues while going lipo cuz i ran the 9920. I may just stick with BK

If you have heat issues with one ESC, you most likely are going to have heat issues with just about all of them. The higher current ones generally have less output resistance so will heat up less under lesser currents, but getting a high current ESC isn't solving the problem. It shouldn't heat up that much. There has to be a reason for the heat; excess drive train drag, slightly incorrect gearing, or inadequate batteries. Even with all of these things set up ideally, running at full throttle for extended times tends to heat them up too.

A 50 deg. variation in thermal cutoff has to make a difference.:032:

Yeah, I'm sure it does. One thing the MM has going for it is the fact that the heatsink is directly on the FETs, while the Quark has those pads. While supposedly thermally conductive, they do have some thermal resistance. It sounds like Quark derates the cutoff to allow for this. Ever since I took my 125B apart and got rid of those thermal pads and used epoxy, the heatsink gets hot quicker and cools quicker indicating better thermal efficiency. Overall temps are less too. So it acts more like the MM heatsink. Since then, I haven't it get anywhere close to too hot to touch.

this is the weird part for me Brian, my esc is not necessarily HOT. I can touch it and keep my hand on it, same with the wires that come out that go to the motor. What happens (i'm sure you heard this already) is that it jsut stops. If I bump the brake then it'll go again for another 3-4 min, then stall, give her a bump, and off I am. And this is on a track jsut doing laps, not really using any brakes either. I called Qaurk, and they said to send it in, but haven't yet. The reason is because I can run for about 15 min before this starts going on.

That is just weird. I can run through 3 sets of 14xGP3300 packs in a row and there is no such action. I wouldn't trade this ESC for any BK; the programmability and contruction alone were worth it.

I would definitely send yours in. I think you'll love it once you get it running right. Don't give up on it yet!

Have you tried a rx pack on it first. Maybe the ubec is cutting off or losing connection.

would the ubec do that though? it seems weird as I'm not the only one that his this particualr problem with it cutting out like this. What would cuz it to do this after 15 min or so?

Well, this is kinda reaching, but the UBEC could be a culprit. After some time loading the UBEC, it will get a little warmer and might change some if its characteristics. Switcher regulators can be "fussy" at times if not designed exactly right. Try adding a capacitor to the power and ground leads of the unused Rx output. This will at least clean up some of the possibly noisy power going to the Rx. If the power going to the Rx is not clean DC, the signal coming out might not be pretty either and the ESC might get confused. Adding a cap is always a good idea IMO; not only does it help clean up the DC, it also provides a little more current capacity so the UBEC doesn't have to work so hard to provide fluctuating current demands. I usually use 1,000uF and 10v to 16v.

To see if this would even help, try using an Rx pack first.

Great will do. So see if the rx pack can remove the glitch i get where i have to tap the brake before the truck will go forward. Also, can i get these at radio shack perhaps? Or would you have a link?

I would use a receiver pack first to make sure it IS the issue. Use a cap or larger capacitance (uF) value along with an extra servo end you may have laying around. Just remove the signal pin (white for Futaba, yello for Hitec, etc). Or, for a few bucks more, just go to your LHS and see if they have one. They might be called something like "voltage protector" or some silly thing, but it's the same.

OK, will do the rx pack first. It may be awhile before i get my truck back together. Now when i wire this thinkg if that is what is needed. You stated an extra plug. So, would I not wire this to the ubec wires? Can you do a quick idagram for me so I can get a better idea how to do this? thanks Brian!

Spektrum makes a capacitor to go in the 3rd channel of the rx. It supposed to
help with some situations. If you have an extra plug for rx. Just wire hot and
ground to the cap and plug in. No extra work required.

That sounds easy enough to do. The problem with that is that my third channel is running my fans! ARG! LOL any ideas?

Y connector or solder it in to the wires. Try the rx pack first. No need in worry
ing about stuff if not needed.

You can run the cap on any channel that you have free (in your case, maybe only the battery in slot may possibly be open). If they are all filled, run the positive and negative cap wires right in parallel with the fan.

Again, this is a long shot, so don't be surprised that it doesn't help - but it wouldn't be the first time random noise caused problems. This is why I said to run an Rx pack first as a test. If it doesn't work, then you don't have to go through the bother with the cap, although it certainly won't hurt to do it anyway if you're bored.

Usually, when something electronic starts acting up after a while, it is usually related to heat, or constantly running hard.

Something else you could do is carefully cut the shrink wrap off the BEC and inspect solder joints. Cold or poor solder joints could cause things to act up as well since there isn't a solid, low-resistance connection. This is especially important for high speed switching regulators. They need very solid ground paths to prevent feedback to nearby parts and device leads.

Thanks Brain. I'll definately go with the RX pack first, but I like to be prepared for the worst! If it is my ubec, then that's the third one now from the RC Monster store that has not worked well. May be getting a new one again! The one I have has not even had 4 runs on it yet i think, somewhere in there, maybe 5....

If you do pull the shrink wrap off the BEC to inspect the solder jobs, please take some nice, crisp photos of both sides of the circuit board. I'm especially interested in the switching IC that is used. I got a UBEC from ebay that is tiny, 5v/6v selectable, capable up to 3A continuous, and only costed me $11 shipped, and would just like to compare designs. The one I have has very few components and the loaded DC voltage looks quite clean on an o-scope.

Will do. Wish I would have known that you were looking for this earlier, I just threw my old on away a few weeks ago I think.