Quark on 6S with Mega 6 pole

Originally Posted by speedracer1129

I would agree with you, but I can't due to the following. Mega recommends only CC ESC's and they have no issues running a CC ESC that was designed to run a 2 pole motor?!? This leads me to believe that the Quark programming has alot to do with it. Worst case scenario, the guys at CC could maybe speed up the MMM a little( ugh, ugh) and I will go that route. We will see....

There should be no difference in terms of which ESC can run however many poles. Sure, firmware has a part in it, but the ESC is still limited to firing the phases only so fast (whether it be firmware or hardware related, that limitation is still present). The more poles you have, the more phases that are in the motor, so the mork work the ESC really does have to do to create one revolution.

Mega also suggests keeping their motors under about 50,000 RPM on their motor selection tables. I'm willing to take a shot and say that this is due to their higher pole counts, and relates back to what What's Nitro was saying. That's also probably why they run just fine on a mamba ESC (the RPM that the motor spins is significantly lower than the problem setup mentioned by the OP).

I'm inclined to agree with him 100% that the number of poles coupled with the voltage it is being run on (a 6 pole motor being run at around 60,000 RPM is going to stress out the ESC, and the gearing is some nasty icing on the cake) is certainly contributing to the problem.

[sikeston34m]

I have wound 12 pole outrunner motors quite high with direct to diff configuration with NO problems using the Quark 125 Monster Pro. 12 pole motors require twice the switching per revolution as a 6 pole motor does. I've wound the 12 pole motors up to around 25,000 rpm's. I don't think the Quark switching ability is the problem really.

After taking another look at your setup. You have quite the Battery configuration there. It can definately deliver. Just guessing, 220 amps continous, probably somewhere about 300 amps Burst rating.

Ok, with that being said. Mega only recommends winding their Mega 22/30/1e to around 44,000 rpms and only rates this motor up to 12 nimh cells or 4S with a current draw of 70 amps max. On 6S, it's going to spin 63492 rpms and will definately overheat very quickly even with dumptruck gearing. I can only imagine what the amp draw is doing with the tall gears, especially on take off.

I would try 5S with lower gearing, like Linc said. Then maybe, just maybe, move up to 6S, only after being comfortable with the temps you are seeing on 5S.

[speedracer1129]

I deal directly with Mega as this is a test motor they sent me to test this setup. There ratings are actually underrated. When I approached them with this project, I learned that there ratings posted are based on what they thought would be the max "usable" RPM's out of the motors. They have been extremely helpful with this project!!! Also, keep in mind that those RPM numbers are unloaded. In the car, it is a different ball game. I should be receiving my Eagletree V3 tomorrow so I will know Wed. night exactly what is going on and take it from there.

[Finnster]

The controllers themselves have a max rpm rating as the others have eluded to. What is it for the Q125? I remember the 9920 was rated ~150K rpms for a 2-pole motor. Since the Mega is 6-pole, the max rpms is going to be 1/3 of that, ie 50K rpms.

If you are trying to run a 6pole at over 60K rpms, you need to have a controller capable of ~200K rpms on a 2pole.

Also, the ET is an invaluable tool for figuring out the specs of a system. I think maybe you need to backoff the gearing and voltage and work your way up befoer trying to blow off the barn doors on the 1st run. This is an 1/8th scale car right? Really you are looking at prolly 2500W peak watts or so already on 4S if you are doing 69. You may be pulling close to 200A already. I'm not so sure that is the right controller for what you are trying to do. A MGM 22018 may be better and would run 6S more reliably as well.

[speedracer1129]

Ok, quick update. I have discovered the problem. No, it was not the gearing (thankfully)!! The problems is that the batteries have no balls!!! I lost 4.5V under load pulling 124amps. So what kept shutting down the system was the LVC!! You think that Quark would have put somewhere what the blinking lights mean..... Neverless, I am happy that I have confirmed this with Quark. I also tested another car with a 4S setup on a Feigao 2pole setup with lower gearing and got the same problem. So, I am going to double up the packs to run a higher C output on the 4S setup to confirm the problem, which hopefully will put everything back into high gear!!

[sikeston34m]

Originally Posted by speedracer1129

Ok, quick update. I have discovered the problem. No, it was not the gearing (thankfully)!! The problems is that the batteries have no balls!!! I lost 4.5V under load pulling 124amps. So what kept shutting down the system was the LVC!! You think that Quark would have put somewhere what the blinking lights mean..... Neverless, I am happy that I have confirmed this with Quark. I also tested another car with a 4S setup on a Feigao 2pole setup with lower gearing and got the same problem. So, I am going to double up the packs to run a higher C output on the 4S setup to confirm the problem, which hopefully will put everything back into high gear!!

Ummmm, Usually when you get on the Quark LVC, it acts like a stutter box. It cuts the power. The ESC completely shutting down would not be the LVC IMO.

If you over draw your packs to the LVC, the voltage should quickly come back up and enable you to run again. Maybe not at Wide Open Throttle, but It still should respond to throttle inputs instead of just shutting down.

[speedracer1129]

Well, I have done some more testing. I ran 2 4S packs in parrallel to try to see if I could compensate the voltage drop and resolve the issue. I was wrong!! That did not work. The LVC still kicked in inspite of the 8500mah now available to the system. As a last resort, I am going to try a smaller motor. I am currently running a Feigao 7L in the car. Thinking about going to an XL. Any input would be appreciated!!

[BrianG]

Your ESC is still shutting down? Did you measure the voltage with the Eagletree to ensure the voltage is staying above the 3v/cell threshold? What kind of current are you pulling?

[speedracer1129]

Originally Posted by BrianG

Your ESC is still shutting down? Did you measure the voltage with the Eagletree to ensure the voltage is staying above the 3v/cell threshold? What kind of current are you pulling?

Yes, ESC is still shutting down. I pulled max 124 amps on the single pack setup, so I would assume that doubling the amperage available should have dropped those numbers, but I guess not. I did not have my V3 with me, so I didn't get any actual numbers.

[BrianG]

Actually, your amperage might go up a little with higher capacity packs since the voltage won't drop as much under load. But as long as the total pack Ah capacity X the C rating is greater than your current draw, you should be ok. If the pack voltage is still dropping below the 3v/cell LVC threshold, then I would say that the pack(s) aren't fulfilling their advertised specs.

[speedracer1129]

Originally Posted by BrianG

Actually, your amperage might go up a little with higher capacity packs since the voltage won't drop as much under load. But as long as the total pack Ah capacity X the C rating is greater than your current draw, you should be ok. If the pack voltage is still dropping below the 3v/cell LVC threshold, then I would say that the pack(s) aren't fulfilling their advertised specs.

That they are!! I had measured a 4.5v drop under load!! Logged in at 16v, max drop was 11.5v!! I spoke to FP about it and they told me the packs were wrong for the application. However, they told me that if I doubled the packs, it should have helped to further confirm that, but it is still doing the same!! This project has been very frustrating!!!!

[BrianG]

How are pack temps? If they are dropping that much with ~120A current, they should be quite hot. A 4.5v drop at 120A is 540 watts! That kind of power should easily be able to be felt as heat somewhere. Granted, that's burst power, but still a heck of a lot!

If pack temps are within acceptable limits, I would start looking at contact/wire resistances. A voltage drop ANYWHERE from the battery, wires, or connectors will cause issues. An easy way to find problem areas is to feel for higher temps manually. Where it's hot means there is resistance (=v drop). So, after a run, feel various places and note higher temps.

[speedracer1129]

The packs are warm after the run. The hottest location in the whole setup is where the wires come out of the ESC, and those temps are really not out of the ordinary, about 140-150.

[BrianG]

Then, that v drop must be very momentary or you would DEFINITELY feel the heat. Ever feel even a 60w light bulb?

Have you tried decreasing the "torque selection"? It's not supposed to be used for amperage management, but if the motor isn't trying to ramp up so fast from a stop, it will by nature pull less current.

Also, what battery setting are you using? Lipo normal, lipo high, or manual?

[speedracer1129]

Originally Posted by BrianG

Then, that v drop must be very momentary or you would DEFINITELY feel the heat. Ever feel even a 60w light bulb?

Have you tried decreasing the "torque selection"? It's not supposed to be used for amperage management, but if the motor isn't trying to ramp up so fast from a stop, it will by nature pull less current.

Also, what battery setting are you using? Lipo normal, lipo high, or manual?

I am using Manual, 3v per cell.