Quark 125B / Sky Technologies
 

Does anyone know if Sky Tech is doing anything to improve the heat issues with this esc? I have only spoken to them once so far, but was interested to see if anyone has heard or discussed anything with them?

Thanks.

From the last ive heard, they will not touch the 125B, but will come out with a even better (higher amp and cell capability) controller.

That makes me a little concerned. The 125B was to handle 6s, and does not. And if they are not willing to correct what they already have out there, then I don't know about buying the next in line product....
Higher amp could mean more temp IMO. And if they use the same technology they used on the 125b? Not sure. Hopefully, they can do it better than the 125B as far as temps go.
I like the Quark, but an esc should be able to handle the draw so it does not get so hot. Having a smooth esc is nice, but it also needs to handle to temps to it's specs IMO.

My thought exactly. We will have to see what happens.

I would like to know about this new controller. But like I said, if they are using the same type of engineering on the inside, then the heat issues are not goign to be resolved at all. You may be able to run more juice, but what good is that if you continuously over heat?
Do they have email?

If my mind remembers correctly, jhautz emailed them about it and came up with this answer, maybe pm him or try searching for the post.

Hopefully they are learning some leasons with the 125 and will address these issues in the new generation. From what we have seen, they could have a really nice controller with a few tweaks.

I'm not sure what they can do about the current production... may not be simple to make changes on the fly. I think they should acknowlege that the heat sink is a poor design... and allow us to do the thermal epoxy mod under warranty... or at least not throw a fit if one is sent in for repair and this has been done. (and not a hack job)

I'm sure he will chime in, but I think you are right Glass. I can understand that they cannot make changes in production on the fly. But like you said, Let one that has real experience do the mod and maybe send it to them so they can incorporate this idea. Email for Sky anyone?

Sky will have to use whole new FETs for any higher voltage ESC since the ones they are using are only rated for 30v. The datasheet for the 125B's FETs is attached.

I'm not sure the thermal problems are because of a poor heatsink. Look at the MM; it's almost the same current rating and the HS is much smaller. The resistance of the MM is claimed to be 0.0003 ohms, while the 125B is claimed to be 0.0036 ohms. That might be part of why the MM runs cooler.

Sky can do a few things to make it cooler without using a large HS: Run FETs with lower RDSon, use more FETs to lower the overall RDSon, and make the FETs switch better (reduced slope, not increase in speed).

I really don't think they will allow internal epoxy being used because it won't allow them to take it apart to fix it.

Edit: Forgot to attach the datasheet. :dft009:

Hey NewE... I did discuss the heat issues and the 6s issues with Frank over at S&T in Cali. What I was basically told is that they knew about those problems but had no plans for chages to the current ESC line. The way it was told to me was that the 125B was originally inteneded to be the ultimate 1/10 scale ESC, but it wasnt really intended for MT and 1/8 applications when it was originally designed. They themselves have done some experimentation with the 125 in Emaxx and 1/8 buggies and have had about the same sucess we all have demonstrated.

When I asked if there was a revised version of the 125 planned to address the heat an 6s issue I was told that there would be no revisions, but that they (S&T Korea) have high on the project list a new ESC that is more traditionally designed with the heat sink on the top that would be targeting the large scale brushless stuff like the Monster Trucks and 1/8 Buggys and Truggys.

Other than that I dont really have any additional information. I asked more questions, but at that time(last fall sometime) it had not even been started, so he didnt really have any more info than that. There was no mention from him as far as max voltage or anything else. I dont want to start any rumors of what it migh be cuz I dont even think they know what it will be. Who knows when/if it will arrive, but if they are gonna play in the same arena as the MMM when it comes out they better do something. Not sure what the MMM will be like, but knowing CC Im sure it will have an impressive set of specs.

EDIT: I just hope the price tag on this new ESC doesnt go up from the 125B cost. Right now its already an expensive controller. I cant imagine many will buy it if the cost goes up from there.

Maybe it sounds a little off, but it think it's time for the MMM to show up. I think it will shatter the quarks. No matter what Quark is going to produce, the MMM wil be my 'next generation' controller. it will force them (or any BL controller producer) to produce BL controllers for a low price.

the programming on the quark is a true PITA..

Thanks for the info Jhautz. From my understanding as well, they really do not repair esc's but "replace" them. And I agree, the MMM will be top of the line. otherwise, I may just go back to BK stuff that I started with. I can keep them cool, and they are dependable for the most part. With my exp on my radio, I have also managed to make the BK's a tad more responsive as well a long with the programming thru the puter.

And serum, I never thought I would hear you say that! I agree, the Quark is a PITA to program! You first told me it was easy when I was having issues! LOL...in comparison to the MM, it definately is a PITA....but, once you get it, you got it. I have not had to re program my Quark since I have set it...I'll say that!

Once winter passes, I really want to test my Neu on the Quark to see the differnce is between the 10xl and the Neu as far as temps on the esc. I'm guessing quite a bit due to efficiency, I also dropped from 5s to 4s, so I'm hoping all this will make the difference.

yeh i hope the mmm is all it seems to be now... i know it will, or the mm gets the 4 pole update that will be SOOOO COOL! then that will truely be one of the best controllers

The thing is, the Quark is not a BAD esc really, but when you have the MM that is better, then it makes the Quark look like, well, ah, yeah....

It makes the quark look like a gigantic overpirced silver box with the same capabilities.

The quark is rated for 6S but works till 5Sm the mmax (les than 1/2 the its size) is rated for 3S but works like a charm on 5S most of the times. Costs less than halve..

yeh lol which is sort sad... and i know cc has a esc with INSANE voltage capability, it has to have a minimal of 16 cells.. so i think the mmm will be the best out, and if it works the the mm then it will go over its limits even father then most speedos out there for less money then the quarks and all

and i wonder what the motor will be like :D

I actually think the Quark is easier to progeram than most ESCs on the market. Try programing a Mtroniks if you think the Quark is a PITA. And there is nothing to program on a BK. I do agree that usb programing is the way to go, I did mention that to Quark when I talked to them and they said that they were already thinking about that for the next gen. So maybe... and thats a big maybe MMM will have some competition.

The biggest thing Quark has over the rest of the competition is that they have excellent service. ESCs are repaired or replaced VERY quickly. In my experience as good or even better service than CC. I have had an ESC in at CC for 5 weeks now. Last I heard it is going ot be replaced, but they are out of stock so I have to wait to get the replacement.

EDIT: And I still havent found a smoother esc anywhere. Nothing coggs on a Quark.

:004: I hope we can say that about the MM soon. :010:

I agree with that Jhautz. I can never get my Quark to cogg. Not even holding the truck and pulling the trigger. The motor still responds like it's sensored. the only thing I don't like is the heat issues!!!!!!!!!!!!!!!

Serum, I also agree, a bit over priced compared to the MM esc. And, the mm is easy to program.

Glass. That would be awsome if we could use the Neu with the MM with no issues with starting and what not, it would be one of the best set ups out there!

I agree with the heat issue being s BIG negative on the Quark. But once you get it solved with a heatsink or fans, it a hell of an ESC. The MM is probably the best deal out there for its price/capabilities. Ever=yone says the MM runs 5s, but its no better than the Quark on 6s IMO. Its a borderline setup thats just asking for problems.

The Quark is a solid 5s controller and the MM is a soild 4s controller. If the MMM is a solid 6s controller with all of the feature in the MM, there will be no match for it. Escpecially if its cheaper than the Quark. I know nothing about it but my guess is that it will be around $200 - $225. That seems like it would be a sweet spot for it.

The heat issues are a definate neg side, could be worse. I think 225.00 or so would be great for an esc that has the capabilities that the MM has!

yeh id pay 250 for a esc like the mm, but with higher capabilitys

Is quark a 6S a123 cells capable?

Well, I know that the Quark does not do well on 6s for lipo, not as familiar with the A123 cells, but I would almost assume no...

That would be a good test. I think its a 50/50 chance. Somebody should try it out.

in theory it should be ok as nominal voltage is 0.4V less than LiPos and 6S A123 has same V as 16.5 NiMh

Ah cr@p. I picked up a 125B and now I hear about the heat issues. Since I committed, where can I find info on these sink mods? Are these issues insurmountable with a small fan? thx

Basically, you can use whatever heatsink you want depending on your application. I've used an 1/8" thick angle aluminum with a small heatsink mounted on the "leg", some have used jhautz's heatsink, etc. Whatever will work for you. Just use thermal epoxy to secure the heatsink to the back of the Quark case. Once you do that, you won't have heat problems and you won't even need a fan. Even without the mod, I've never thermaled; I just wanted my ESC to run as cool as possible.

About the fans; some swear by them - I try to avoid them if possible. It's just one more mechanical thing to go wrong and they tend to go bad faster in dusty track environments. Just my $0.02.

Thanks for the input Brian. My plan was to mount the esc bottom side directly to my CRT chassis via CPU paste. Not sure if you've seen my CRT project thread but there's pics there showing the plan. I also don't want fans. Fans are band-aids. Use them only if you have a boo boo is my philosphy. But from reading above, it read like there was an issue with how the Quark conducted heat from the innards to it's own case. If this is the problem, my external chassis sink plan wouldn't have helped. I will be running a Neu 1515/2.5d on 5s. Think I am ok?

I havent tried it but the A123 cells dont peak at as high of a voltage as lipo and my quark runs 6s fine after the voltage starts to come down a little. I would tink the 6s A123 would be just fine.


Your OK. That should work great.

cadima, you are right; inside the Qaurk there are two thermal pads (about 0.5mm thick) which secures the FETs to the case and also transfers heat to the case. It's not perfect but it works ok. The best connection is direct obviously, but I'm thinking Quark wanted a way to firmly secure the innards to the case (and transfer heat) while allowing them to be removed for any repair work. Thermal epoxy works better by far than these pads, but it considered permanent. No taking it apart after that. Using epoxy would void the warranty.

After a while of track use, one or two people have seen the pads slowly get dusty and eventually seperate from the case. Obviously, this is not good for heat dissipation, but usually happens after the warranty is over. If this happens before the warranty period is up (90 days IIRC), I would send it back to Quark for repair. If out of warranty, you can do the mod if you think you can do it.

On my Revo, I did the mod since it was out of warranty anyway. On my buggy, I didn't touch the insides in case something happens. After a while, I'll probably do the epoxy mod to that one as well.

BTW: If you use normal CPU "goop", which is NOT adhesive, you'll have to find a way to somehow clamp the ESC down so it doesn't move around at all. Any movement will slowly render the goop less effective.

I was planning to have a clamp on the quark, for peace of mind. If I alternatively were to use epoxy how would I get it off the chassis?

Even though thermal epoxy is considered permanent, you can remove it, but it's quite a bit of work. First, freeze the chassis/ESC in a freezer for about 1/2 hour. Then, gently use a screwdriver to pry up. It should pop loose with a little force. Now this is where the work comes in; use a flat exacto blade to scrape off the epoxy. I would use a fresh one to avoid scratching the surface too much.

I know this works because I've done it twice. It works good on something rigid like the case, but I definitely would NOT try it on anything directly attached to the FETs. Chances are the solder joints on the FET pins (or the pins themselves) would break before the bond would.

Can you shoot me a few leads on some of this conuctive epoxy? I'd like to entertain this idea in detail, adn learn of it's transfer properties in comparison to my silver paste.

I always recommend Arctic Silver epoxy. They have two types; Arctic Silver Thermal Epoxy and Arctic Alumina.

The thermal epoxy has silver particles in it. While not truly electrically conductive, it can exhibit capacitance. So, you don't want to get this stuff on any electronics, like the legs of the FETs. It works fine for the main case though. I say all this, but I did use this on my FETs - you just have to be VERY careful that you use a very thin layer just enough to adhere but not squish out and get on anything else.

The Arctic Alumina is totally non conductive/capacitive. So, this is the stuff to use on the FETs if you decide to go that route.

BTW: The freezer trick works on the first one, but I'm not sure about the Alumina stuff.

I do know that thermal epoxy does not transfer heat quite as well as a good thermal goop, but if the surfaces using the goop are allowed to move around, this would make the goop worse than the epoxy.

I've never messed around inside of a Quark, but I used to do a lot of work with small DC/DC constant current converters. .5" in diameter. These things generated heat and I used thermal epoxy (arctic alumina) to "pot" the converters. Occassionally, I'd have to get back at the current sense resistors or something. What I did was to bake the assembly in a toaster oven set to about 170F. This makes the epoxy spongy, rather than super rigid, and then you can take it off in chucks with an exacto. Like I said, I've never tried this with a Quark, but the heat does have that effect on Arctic Alumina.

If you are going to try this, I should add that you need to preheat the toaster oven to 170F and let it sit for a while, before sticking the PCB, or whatever, in. Ovens tend to spike the temp way over the set temp just to attain its goal temp. Once it preheats, then it will stay at the set temp.

Good info.... but AAngel is now aka Julia Childs :D

lol, funny GD. :)

So, heat works for the Alumina, and freezing works for the regular thermal epoxy. That's kinda odd. The heat approach relies on softening the epoxy while freezing it relies on making it brittle.