Quark VS. MGM?
 

Ok, I would really like to know some people's thoughts on these two ESC's. Specifically for my given situation. Does anyone have experience with both of them to compare? My setup is in a CRT and my motor is the 2700kv Neu 1515 and my battery is a 4s Flightpower 25C 5000. What do you guys think is the best ESC and why? Thanks!

They both have there weakness's. It just depends which problems bother you the least. With the Quark, you'll have to do the heat mod, since it seems to have a problem overheating and it can't run 6s, if you ever plan to in the future.

The MGM runs stone cold from what I have heard, however it also has a problem with the braking/reverse from what people are saying. However, since you are racing, you may not want the reverse or it may not be allowed, so then it doesn't really matter for you. Mike should be getting the programing stuff in the store very soon, so you can program the ESC on the computer similarly as you program the MM ESC.

My only thought would be with the hi kv motor you have, you may pull lots of amps. This will be esp challenging for the Q125. I might feel safer going w/ the larger MGMs, but that's just my guess.

Have you ran the motor at all? Or just waiting for an ESC? Curious on the performance you got out of it.

Just a side question, not to hijack the thread, but does anyone know if Quark changed anything in their design to prevent the electronics from detaching from the case, or do they use the same thermal tape? I got mine early 2006 and it came loose after about 3 months. I think plugging the side holes a bit better might prevent the fine dirt and dust from ruining the tape, which is what appeared to happen in mine.

I have them both.


The new MGMs are really nice. I like them alot. It runs alot cooler than the Quark. USB programing is really sweet. You can change all of the programable ESC prameters with it easy as pie. However, dont put to much positive on the USB programing thing. Its nice at first, but once you get it set where you like it you pretty much dont touch it any more so the USB programing thing really isnt that big of a deal IMO. But the thing that the USB does do, that is a big deal IMO, is the ESC actually has a basic data recorder built in it which is really nice to have. It records the Peak Amp draw, the Voltage of the battery when it was unplugged, the Max Motor RPM, and the max temp of the ESC. Damn good info to have and you dont even need an outside device to collect it. Also the fact that it has a built in Switching BEC for up to 6s lipo is huge IMO. One less thing to wire. Gotta love that.

Now the bad... The reverse/brake thing is annoying, but at least it alot better than MGM used to be. It only does it a very low speeds so its not going to damage anything like if it did it at high speeds. I wound up disableing reverse to eliminate the problem just cuz it bugged me. I really didnt use reverse anyway. The other thing is the shape of the ESC is rather hard to mount well IMO. The flat bottomed, hard case of the Quark is very easy. The MGM with heat sinks on both sides takes more creativity, but that little thing is worth it to get the extra heat sink.

There are extras needed to purchase with both the get the most out of them. The Quark NEEDS a heatsink at a minimum to run well, and many need to be taken apart and heat moded. The MGM needs a special USB data cable to program it via USB and use the data recording feature. Neither one is a very expensive item, but they are extras you will buy on top of the base price.

If I were to buy another ESC I would for sure go for the MGM again. But thats just my opinion. They are both still very good ESCs, and I have both in service right now. Its just a matter of what minor issues are more tolerable to you and th Quark heat just pisses me off.

Forgot one important point. Quark Service is top notch. I have a friend of mine that has fried 5 of the Quarks (he really pushes them). This is bad, BUT... Quark has also replaced it every time for FREE under warantee in less than 2 weeks every time. They have excellent customer service. MGM on the other hand I hear my be dodgy, I dont have any first hand experience with them so I can't comment personally, but from what I have heard from others, there is room for improvement from MGM.

Thanks for the info jhautz. The MGM sounds very, very nice. I think I'll have to add it to my endless list of to-buy things. I never though any ESC would come with the feature to record the highest RPM, temp, amp draw, etc. Very nice touch in my opinion.

as with jhautz, I also have both and would get the Mgm if I had to buy another esc now. The reverse issue still exist but doesn't bother me because I run all my esc's in forward only. It also runs much cooler then the quark and doesn't need an external bec.

I can't comment on the usb features thought because I am waiting for mike to get them in stock.

I have a quark & have yet to do the heat mod, All I have done is I run the 30mm fan heatsink...mounted vertical to the rear ext. on the chassis and then have the quark mounted to it...and I run (2) 5vdc 30mm fans and it keeps real cool, and has zero issues with heat...to date....
like in the pic....
http://img.photobucket.com/albums/v4...s/DSCF0297.jpg

Yeah, after a while the thermal pad starts getting loose and can thermal. Since the FETs are no longer touching the case, the case feels quite cool. It's best to measure the PCB near the motor wires.

Well guys, I really appreciate the info so far. Although I'm not sure if it's helping me or making it more difficult :)

Anyway, I have run this system and it works great but I had been running it with my MM ESC. It's been acting funny lately and it started getting me nervous so I pulled it. I'm not sure what kind of amp draw I'm getting and I guess that's my biggest unknown for this whole deal.

On top of all of this, there are 3 Quarks on ebay this week and no MGM's available. Plus, I have no idea when they will be in. One of the guys on the forum has the 8s MGM 160 amp version that he'll sell me, but I don't need that. If anything, I think I would need the newest 160 for $275 or maybe the 224 for $375. But again, Mike is out of stock and I can't find out when they'll be in.

Just keep in mind that the Quark and MM use the same exact FET parts and the same number of them. So, disregarding the PCB traces and physical layout, they really should be rated the same; either 100A or 125A.

Good point Brian. Well, heck, now I'm thinking the MGM 224 is the ticket. Now I just need to see if I can find out when they'll be available. I've been sending Mike PM's for the last two weeks with no reply. Anyone else have any insight on them? Or, does anyone have better response from Mike and care to ask him for me?

I would think the 160 should be more than enough, especially since MGMs tend to stay cooler...

You think? Even with my higher kv motor (2700)? I know the MGM can pull a 200 amp spike for 5 seconds, but I just get nervous with my past experience of a company saying they have certain specs and then not performing.

you can try emailing mike

I thought that was the same as a PM. Shouldn't he get both? Is there a preference for him to check one or the other? In the past he might take a couple days to get back to me, but never this long. It's not like I've never bought anything from him either. I thought I was a "good customer". I'm sure he's just really busy. But I sure would like to know when the MGM's will be in.

yeah i am not sure but i think that the email he checks more frequently than the pms. BUt i could be wrong give it a try (the email).

I think Mike is really insanely busy lately. Theres more work than he can do in a day and hes been killing himself trying to do it all. He really does bust his hump to get back to everyone, but lately rather than answering email in little batches I think he sits down and batch process them in one long session when he gets some time.

Last time I talked to him (a couple weeks ago) he told me he was working 60hrs a week just to keep up and then the rest of the time on all of the custom work and such. All I can say is I'm glad I'm not him.... but I'm sure glad he's there.

I hear ya. I'm not trying to come down on the guy by any means so I hope it doesn't sound that way. I think the he's awesome and I'm waiting as long as I can to give him business because I love this site and what he's doing. It would be nice if he had someone help him out a little though. I just sent him an email, so we'll see if that gets any reply.

The motor kv is only part of the story as much of the current draw depends on gearing, weight, tire size, rolling resistance, etc. But, if you are currently pulling 200A @ 5s, then maybe a higher current setup is needed. I was just trying to save you a few bucks.

I understand your concern though. I usually try to over-engineer my setups so the ESC has a higher current rating than I think I will need. You may never need the amperage rating, but it's nice to be there just in case. Plus, higher current ESC means more FETs, means less overall ESC output resistance (total Rdson), means less heat for a given current. And we can't forget that these FETs have a temperature derating curve, so it's better to keep temps as low as possible.

As far as contacting Mike, I would email and wait for a response. I know it can take some time, but he gets a TON of emails a day and tries to get to them FIFO (first in, first out). Unless he has email notifications when he receives a PM, the only time he'll see those is if he logs in - and you've seen how many times he does that!

Thanks for the info Brian. I guess I don't really know how many amps I'm pulling and that's part of the problem. How can I tell? My setup is actually a 4s (instead of 5s) Flightpower 25C 5000, CRT pro truggy w/Crimefighters, Neu 1515 . . . and whatever ESC I decide. And my gearing is stock in the diffs, but the center is 10/51. Is there any way I (meaning you :) ) can guestimate the amp draw?

Oh, and by the way, I emailed Mike last night and he replied. He said he thought he had replied to one PM so I think there was just a problem with the PMs. But he said he has the MGM's on order. Not sure how long it takes them to arrive though.

It is VERY tough to estimate current draw without a measuring device like an Eagletree. At best, you can determine the average current draw by your battery capacity and runtime, but it's VERY rough since BL cars are very peaky with current spikes. But, I can say that you aren't drawing 200A constantly since runtime would only be 1.5 minutes. :smile:

What seems to be pretty accurate is to figure out your average current draw by:
(battery_Ah X 60) / runtime_minutes
Then, multiply this value by about 6 to get the approximate peak current. It's not scientific, but from the various graphs I've seen, it seems to be pretty close.

4s, 4.3:1 F/R diffs, 1515/1.5d (2700kv), 5.1:1 CD gearing, 5.75" tires should give you a speed around 40mph. Is this what you are shooting for?

That's exactly what I've been shooting for, and that's about what it was doing when I was running it with my MM.

My run times were usually a little more than 1.5 minutes . . . more like 3 or 4 minutes. Just kidding. The pack is pretty new so I don't know for sure but I would say it was close to 15 to 20 minutes depending on the driving style.

Assuming 15 minutes for runtime, that means your average current draw is ~20A, which seems a little high for that vehicle, but not too bad. I would've thought the average would be ~15-17A, but that's OK. Anyway, using the rough 6 multiplier, the peak current is 120A. Again, this is approximate, but is probably pretty darn close.

Well, that at least gives me some kind of idea though. That basically tells me that the MGM 160 should work just fine - even under racing conditions when my run time will be more like 10 minutes on a wet/high-traction track. Thanks a ton Brian.

I would really like to get an Eagletree though. That would be sweet. Are they very expensive or difficult to use? Is there just a little box that plugs into your reciever or what? I've never seen one.

The Eagletree is a small device that plugs in between your batteries and the ESC. It samples current and voltage every 100ms (sample rate is adjustable). From that information, it can compute power and other things. You hook it to a PC and can generate graphs showing these values.

http://www.eagletreesystems.com/MicroPower/micro.htm

The unit itself is ~$70 and has other sensors you can add to measure rpm, temperature, etc. The manual can be found here.

It is rated for 100A, but can log up to 130A IIRC. Eagletree makes another recorder (in the "Pro Products" section) that has an optional hookup to measure up to 300A, but is more expensive. Just the 300A measurement add-on is $130, but not sure if is compatible with the e-logger unit. You might want to call/write them to see what your options are for your application.

Nice, thanks Brian. I'll look into that.

+1 for the eagletree. I've got one and it's been really revealing on how my systems perform. I went ahead and got the RPM sensor and the temp sensor too. All together, it gives you a really darn good picture of what's going on. The unit itself is $65, add'l sensors range from $10 for the temp to $14 for the rpm. I think it may even be possible to add a G meter to it too. :) Hottest spike I've recorded is 116A with my setup.

Sleeb

Nice . . . so what's your setup Sleeb?

I think that one came from running a RC10B4 with a 7700Kv motor and feeding it with a Apogee 2S 3800mAh pack. That one was really hot, usually it hits 100A - 110A on initial acceleration. I'm attaching a graph of a similar run, I don't have "the big one" handy.

Keep in mind, this is with running "slicks" (worn out tires, haha) and they don't always hook up that well. Once I get some more grippy tires, I might see more consistent high spikes.

Sleeb