Quark 125b thermaling
 

I am having problemes with my quark thermaling after about 10 minutes of running. I had two of the large novak fans on it and am running 20/66 gears with 1/8th scale buggy diffs. I switched back to my old MGM controller with no fan and had no problemes. I talked to Frank on Radio Control Zone forum, he's a rep for Quark. He said with my setup I will be able to run 6-7 minutes before it thermals? He said brushless technology is new and this is all I can get from their controller or any controller for that matter? I also tried gearing down like frank told me too and it helped but then my truck was lucky if it went 30 mph. I then took it up a gear and it started thermaling again? If you would like to see the posts by the Quark rep here it is: http://forums.radiocontrolzone.com/s...st2033099:031: I was hoping I got a bad controller but after reading this post I dont know what to do. Any ideas?:032:

10lb Emaxx
G-maxx: ext-motor mount-single speed conversion,
BK: Wanderer 7XL
Quark: 125b controller (very nice)
Orion: Platinum Edition 4800 Mah batteries (with 10 guage wires & deans)
Proline: Powerstrokes-towers-bell cranks/servo saver-and arms,
Rpm: hubs-nylon nuts
UE: Bulkheads-idler gear-1\8 8 spider diffs-titanium drives, titanium ball studs
Ultimate BEC
Spektrum: 3000 rec.
Hitec: HS-5955TG Servo
Traxxas: Titanium tie rods
Novak: fans

I read your posts and the replies at the other forum, then put up my own. "tripthreat" appears to be "Frank", an employee of Quark. I was personally disappointed to read this part of one of his replies, so I countered with my real-life experience.


Quote:
Originally Posted by tripthreat
I would love to be able to run a 15 minute main, but right now, there are no controllers that will allow you to do this competitively against Nitro Cars. That is not pesimistic, nor defeatist, it is the truth. If it was defeatist, I would not be looking forward to when it will be possible, and our company would never strive to make a better controller, but such projects and aspirations are in stages of development.


I'd just like to add here that the first statement in this comment is incorrect. I run a Lehner 1940 motor on a BK 9920 controller with 4s2p 6400mah in a converted OFNA MBX 1/8th scale buggy, geared 14/51, and I can run for over 25 minutes without either motor or controller going over 120F in ambient temperatures of 95F.
The big difference is the motor. The Lehner 1940 is considerably more efficient than the Feigao or BK "L" or "XL" cans. Of course, there is a $200 difference in the price, but that makes all the difference in the performance.
If I used an L or XL can in my buggy, both the motor and controller would overheat inside of 7 minutes.
I'd be pretty confident that the Quark could do the same with a higher-quality motor attached to it.

Joe

Gee good thing he don't know I have ran 45 min none stop. :D

How you have your controller set up may be the difference as well.
How you drive makes a difference as well.
Make sure no drag in the truck.

Bummed
 

So I have to buy a new motor?

I dont have any drag brake on and with my MGM 160 I dont have any issues I'd keep it on the truck but I just dont like the way the controller goes into reverse without warning. So I'm assuming my driveline is free, but thanks for the input it is greatly appreciated.
So my gearing is in the ballpark, I've tried quite a few lower combos and by the time it made a difference my truck was much much slower. I was going to go higher but it will only make it worse right?

Gearing higher will make it worse. I had the 7xl heat my controllers up pretty good. You could look in a 9xl. I have run them on a 7020 with no thermal. The problem i see with quark is the case is so smooth it has no fins on it for heat transfer. You could go down in gearing and up in volts. Put another orion pack on it for some get down power.

Are you racing, or bashing? The L and XL motors can handle some pretty hard bashing with no problems. The rigors of racing, however, will take their toll on the L and XL motors pretty quickly.
Many people who bash, even running their vehicles at high speeds up and down the street, and don't race them - they unfortunately don't quite get the difference. I do both; bashing and racing (mostly racing), so I have first-hand experience with the differences and how they affect the electronics we use.
When you bash the vehicle comes to a complete stop many times during the session. For example, if you're hitting a jump in your back yard, you'll line the vehicle up then hit the throttle. The vehicle gets some air, lands, you check out the landing, then you line it back up again. Chances are you just stopped twice within a 15 second period, giving the electronics a chance to rest. The same holds true for high-speed runs - you'll typically stop at both ends of the run.
When you race, you do not let up from the throttle for a solid 5 minutes (or more), so the electronics never get the rest they get during bashing. Most off-road racing consists of multiple jumps and many turns. At each of the points on the track you're doing everything you can to keep your vehicle moving forward as fast as you can control it. If you're using the motor as a brake, you're probably also pushing the brakes hard up to 50 or more times during a 5-minute race. Braking is VERY hard on the controller because the motor is usually trying to halt the progress of an 8-15lb vehicle from whatever speed it was running, then you're immediately back on the throttle again to make it out of the turn and line up for the next jump, etc... The same thing does not happen during typical bashing.

If you bought your electronics to put in bashing vehicles, there's a very high probability that what you bought should be just fine.
If you bought your electronics to put in vehicles for racing (especially to race for long periods like 15+ minutes with nitros), you almost definitely need a higher-efficiency motor.

Additionally, you can look into getting the software updated on your MGM if the only problem you have with that is reverse. Mike has told me that MGM now has the ability to disable reverse, but it requires an upgrade that MGM must perform. I have both an MGM 12012 and an MGM 8012 being upgraded now and I'm hoping to disable reverse on both when I get them back.

MGM now has the ability to disable reverse? If I remember correctly, my first MGM controller from a little over a year ago had an option for forward and brake only. Is this any different?

The first manual I can find for MGM that has an option for no reverse is the manual for software version 2.30, which is the most recent manual on MGM's site. Version 2.2 and earlier did not have this feature.

The 3 MGM controllers I've had were all purchased in the past year and none of them had this software version, or the ability to disable reverse.
If you look in the manual (http://www.mgm-compro.com/manuals/ma...x-3cb-v230.pdf), the option is the first one and is titled "Car mode -> one way". Previous manuals did not have this option.
http://www.mgm-compro.com/manuals-ar...rofi-v-22x.pdf


I actually purchased a 9920 for my buggy conversion specifically because MGM did not have a reverse-disable option a few months ago.

To help cool the ESC, thus preventing thermaling (or at least prolonging it), add a heatsink to it. The nice flat bottom is where the FETs are attached, so use that spot to mount the heatsink. I know it's not the best solution, but it does work. I added a 1/8" thick L bar to my 125B along with a couple PC memory heatsinks (mostly for show) and have reduce temps by about 12 degrees F after about 15 minutes. The added thickness of the aluminum provides more thermal mass to pull the heat from the ESC and more surface area for the heat to dissipate. I'm not how much this will help in racing, but it sure as hell can't hurt!

Of course, no heatsink will work without proper airflow. If you aren't using a fan, then airflow through the truck body is paramount.

Ran a full charge with 20/66 gears
 

I added a heat sink and a different set of fans yesterday. I ran it on my track doing the outside oval for a full charge it went just over 20 min. I got 110 on the controller and 146 right were the wires go in the motor. The controller heat sink was 103 and the motor sink was 130. It was right around 80 with 90% humidity.
I used a trinity motor mount as the heatsink and switched to the small novak fans, which blow an incredible amount of air reguardless of their size.
Quark are you listening?:032:

your problem isn't thermaling if your controller is only at 110. somthing else must be messed up

The highest temps I got were around 125.
And it hasn't thermaled since I put the heat sink and new fans on .
So i'm assuming it was a thermal issue.
Plus the rep sounded like he knew there was an issue by the way he said that racing my setup couldn't be done for more than 6-7 minutes.

Sounds like they need to redesign there case and maybe add easy mounting for fans :027:

squeeforever
Sounds like they need to redesign there case and maybe add easy mounting for fans


Kind of like what the first Novak HV's went through isn't it. They didn't enlarge their heatsinks, which they should have but, the addition a fan gave a higher power rating if I remember correctly.

Yeah, I like their cases because they are easy to mount, but after looking at the thickness of the aluminum, it is really too thin and doesn't have enough thermal mass. Plus, the fins that do exist are really too small. According to their specs of being able to run up to 6s/18cells (~22v nominal) and 125A continuous, that is 2750 watts. At 90% controller efficiency, that's still 275 watts being dissipated on the controller, which is WAYY too much for that little heatsink. To be honest, the heat sink needed for that kind of dissipation would be quite large, even with fan cooling. Like I said, adding more thermal mass would be nice to pull the heat from the ESC, and then adding more/taller fins to dissipate the heat. Don't forget to use thermal compoung between the ESC heatsink and whatever you add for efficient thermal conductivity. I actually lightly sanded the back of the ESC to get rid of a lot of the texture and then used thermal epoxy (Arctic Silver) to secure the ESC to the added heatsink.

Brian, do you have a picture of what you did?

Not yet. My camera was dropped and I have to fiddle with it to get it to work. :mad:1

I'll try to get a pic of it later. The thermal adhesive I used is this: http://www.arcticsilver.com/arctic_s...l_adhesive.htm

The version I used has traces of silver in it (hence the name) so it is advisable to make sure none squishes across connections when you compress the heatsinks together. They have totally non-conductive stuff, but I didn't have any of that. You can use thermal tape too, but it doesn't work quite as good.

Whatever heatsink is used, make sure that both surfaces (the ESC and the added one) are smooth and flat for best contact and thermal transfer. Like I said, I sanded the back of the ESC with fine paper, and then I almost polished the piece of aluminum I used for the added heatsink.

OK, a couple pictures of the heatsink:

http://bgosselin.home.mchsi.com/e-revo/Revo2_esc.jpg

I'll probably replace those shallow PC memory heatsinks with something a little bigger, but for now, it all works quite well.

The flat bottom of the heat sink offers the best surface area for heat transfer and it looks like you nailed it, I'd give it a few runs before I change anything. At most you might need a fan.

Very clean I like it.

I was going to swiss cheese my heat sink but the only problem is I don't know how much I can drill out before it is too much and I start overheating.
I think I'm going to make a few runs in the heat before I start fixing things that aren't broke.

Like I said, the way I currently have it reduced temps by 12 degrees after 15 minutes of bashing around the yard. I am going to remove those small PC memory heatsinks and replace them with two of these, again mounted with thermal epoxy. That should reduce temps even more. I hate using a fan because it adds wiring complexity (albeit small) and it's just one more thing to break or wear out, which is especially bad if you are counting on the fan to keep things cool. I'd rather keep it passive if at all possible and arrange the fins so airflow runs through them. Swiss-cheesing the sink should work as well too - I'd use holes no larger than 1/8" and have 1/8" spaces between them. The idea is to create as much exposed surface area as possible while keeping enough mass in between.

Cutting holes in the top and adding a fan over them would be a good option...

He just said he doesnt like fans squee:p Alot of people think a fan is a type of "bandaid"

Sylvester, I don't particularly like them either. I was just saying. Its a option for some people.

how is a fan a "bandaid"...just think...if your PC didn't have any fans to help keep it cool...you wouldn't be able to use your pc with out it overheating...let alone getting on this forum...I see fans an neccessity in some cases, but a personal preferance on others.....my thought is...a little extra airflow on the controller can't hurt it at all.

Yea, but like brian said, on an rc you'd have to replace them after a while, it can be just another thing to break, takes away some runtime, and adds complexity to the wiring, i dont like them too much, thats why people use bigger heatsinks.

Great site. http://www.accelthermal.com/ Is there a minimum amount of heatsink material you have to order.

I'm not sure. I sent them an email yesterday asking that exact thing. It's funny; there is a link for how to order, but it doesn't tell you how to actually order the stuff. I guess either send an email or call them? If/when I get a response, I'll let you know.

As to the fan thing. I agree that sometimes they are necessary like in a PC (although I had an idea where if the CPU was mounted on the reverse side of the motherboard, you could use the whole side/bottom panel for a heatsink). However, in an RC, you have movement which creates airflow. PCs generally don't move around. :dft012: I try to remove as many mechanical parts as possible since things with moving parts are the first things to go bad. Sometimes though, a fan will be necessary and I can accept that as long as it makes sense and is not used to compensate for a bad design or use.

Personally, I think all these ESC heatsinks are too small. But if I look at it from a manufacturers standpoint, I would want to create something small and light that will fit just about everywhere and let the end user decide how to cool it. If they create something with a big enough heatsink, it might reduce their target audience since some may use it in buggies where room is more of a premium - or maybe the dimensions of the bigger unit won't physically fit where the user wants it to go.

I applaud Quark for making a unit where adding a heatsink is possible without having to seriously mod the unit. And doing this really can't go against their warranty as long as the voltage and current limits are met. Nothing was cut or changed, just added to. Thermal epoxy is considered permanent, but it can be removed if you really try.

Here is the heatsink I'm using right now. http://www.dealsonic.com/thera1ddrsdr.html . It works but does not fit that well. I've got the two heat sinks side by side runing long ways on the quark controller. They are not quite long enough and a little wide. I might order one more set and run them the other direction and cut the extra off. That way it would be a cleaner fit.

I'm a fan fan
 

Fans do have some good points.
I have a lipo setup in my mini lst and on a few occasions I forgot to unplug the battery. Once it drained the lipo battery to the point were I had to charge it as a NIMH battery till it got a charge in it because my charger wouldn't even charge it. I was waiting for it to go boom but it didn't, it also was never the same either and I have since pitched it. There is no misstaking wether or not my Emaxx is on, the little novak fans sound like a turbo spooling up which is kind of cool in itself. Just imagine ruining $280 worth of batteries just because you forgot to unplug your batteries.
As far as run time goes I havent noticed a difference, there is a difference it is using a fraction of an amp but its not noticable.
As far as wiring complexity one more pair of wires isnt that big of a deal.
Just my 2 cents, I never knew fans were taboo with so many people.
In the end to each his own i guess.

I agree: to each his/her own.

BTW: A bright "power on" LED works as effectively, requires less current, less space, and is not mechanical. ;)

so what was the verdict? did you ever completely rid your thermaling issue? i have the same problem. i just wish i didn't have to void my warentee to pick up quarks slack so to speak. i run mikes heat sink with everything but fans and i still only get about 5-7 min befor play time is ovr

My quark has the thermal epoxy mod, sits on artic silencer heatsink and has two 470uF caps (going to add 2 more). my truck is quite heavy with big joes - 6.5kg (or 5.5 in race mode) and had no thermal issues whole saturday after being quite hard on it

http://www.radeks.net/temp/cap1.jpg

I agree; you shouldn't have to mod any ESC. But, the sad truth is that you really need to if you are using it to its full potential. Certainly not the ideal situation, but we don't live in an ideal world.

Well, in a moderate setup, even doing the internal mod to the Quark is the biggest difference you can make on your controller for temperature. But if you are like me, you will put another heatsink to it.

BrianG: I think the Quark is a lot more than 90% efficient :eek: If that were the case, it would be a little puddle of sadness. :005: It must be 96+%.

lol, some of the recent ones are "puddles of sadness". OK then, at 96%, that's still 110w on the ESC - still a lot IMO. The real efficiency is variable and depends on switching speed and if it is running partial load (more PWM cycles since it's not full speed), and no one will run 2750W constant.

I went a little different route and used aluminum angle and heat heat shrink instead of the poorly designed case. Temps on the aluminum never got over 105 f ,this is with a 9.25lb crt geared 16\46 with a neu motor and 87 f outside. The motor got up to 179 f. It then blew a cap so I guess I'll have to try the add a cap thing and see how it holds up.
Two things I noticed about the Quark:
1. It seems to run the motor timing very advanced and tends to make the motor hot. There should be an adjustment like on the MM. It makes the car noticeably faster but the added heat isn't worth the trade off.
2. It also cogged a little off the line, about the same as my MM with a 2 pole 8xl. I've heard people say their Quark neu combo doesn't cog at all so maybe I got a bad one from the factory?