Quark 125b thermaling

[smhertzog]

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

[Batfish]

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

[smhertzog]

So I have to buy a new motor?

[Batfish]

Originally Posted by smhertzog

So I have to buy a new motor? Before I bought this combo 7xl & quark 125b I specificly asked if I would have thermal issues. I stated I wanted to be able to run out a full charge on my Orion 4800's. I would have dished out the extra $ for the lehner if it would have been given it as an option. I bought a pair of 7xls and a pair of quarks for my two trucks. Now I'm not sure what to do.:032: My wife will kill me if I buy a pair of lehners and have almost $200 worth of 7xl's collecting dust.

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.

[coolhandcountry]

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.

[smhertzog]

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?

[coolhandcountry]

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.

[MetalMan]

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?

[Batfish]

Originally Posted by MetalMan

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.

[BrianG]

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.

[smhertzog]

Originally Posted by BrianG

To help cool the ESC, thus preventing thermaling (or at least prolonging it), add a heatsink to it.

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:

[stampy]

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

[smhertzog]

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.

[squeeforever]

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

[smhertzog]

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.