MM temps in Traxxas Slash
 

I'm running the MM5700 in the new traxxas slash. I have a 15t pinion and the stock spur. I belive it's an 86 48pitch. My temps are about 170 With some light bashing in the dirt and a few speed runs on pavement. I was running a 7 cell gp3300. This seems to hot for me. I want to run a 3s lipo but now I'm scared I'm just going to fry the ESC. Does this seem right or do I have an issue with the new ESC? I've seen several posts with people running lower temps than I and I certainly didn't bash it hard yet. Is the 3s going to make it even hotter? Should I get a fan? :neutral: I was really expecting more from this system.

3s will make it hotter unless you gear down to lighten the motor load. I would have thought that any of the MM motors would be too small for something that is fairly large. If going to 3s and gearing down doesn't help, you might want to consider getting an L size motor. 3s on either an 8L or 9L should be fine. The 9L would be better if you think you might go to 4s in the future.

Also, use an external BEC on 3s...

3s Lipo would be better suited to the 4600 than the 5700, I think. Is that temp you mentioned on the ESC or motor?

Temps on both were the same. I sold off my BL emaxx due to constant temp issues. I really want this one to work. I'll drop the pinion to a 14 and see what happens. I was hoping to keep some top end. I can understand the motor being to small, will that impact temps on the ESC?

Yes, a motor that is too small can definitely cause ESC temps to go up. It's all about matching the motor/ESC/battery for the application.

That's acceptable news. If I go with a cheap feigao do you think temps on the ESC will still be high or should I just bite the bullet and get the neu?

A properly selected Feigaos will still get warm after a while, but not nearly as bad and/or as quick as a motor that is too small.

I dropped to a 14 pinion and temps are better.I don't have access to GPS or radar so I couldn't tell top speed but it seemed faster? :neutral: I have a 13, I'm trying that one tomorrow and will report back. It's alot more fun when you don't have to watch the temps. I'm glad I didn't get the 7700. I'm going to assume that the 4600 would be the better choice for this vehicle.




skellyo, how are your temps running the sidewinder?

How is (are) your battery(s)? If it is faster when gearing with a smaller pinion that tells me your batteries can't keep up.

My motor was around 165F after 30 minutes of running in 90F ambient air. The ESC was around 105F. This is geared 18:86 for a top speed around 32-33mph on 2S Lipo. This is also running primarily through the short grass in the vid I posted in the other thread.

Or the high current (from overloading) is causing a big drop in kv. It does make sense that voltage will drop too...

Batteries are older and have been well loved. :lol: I don't mean babied. I mean well used. I did get an occasional cog. I figured that was the batteries having a hiccup. Yes it did seem quicker with the smaller pinion. If the batteries are on their last leg would it run hot with the larger pinion?

It was about 90 here today also. My ESC was much hotter than yours.

Tired batteries would get pretty warm and would drop more voltage under load.

I would also check airflow to the esc. I noticed a significant temp drop on my mm in my maxx when i turned it sideways so the air can flow thru the fins and not just the face of one fin. + the body on the slash is much bigger than a regular stadium truck so it might be impeding(spelling) airflow.

Tomorrow I'll drop in the 13 tooth and see what happens. Perhaps it's the ESC. I don't get the arming tones. I figured that was because the caps were holding the current but it also doesn't appear to enter programming mode normaly. In fact I haven't been able to set it to the remote aside from the first time. When I hold full throttle and turn it on I get a solid red light. Let go and I get a green. I don't know what to think.

Airflow is limited but skellyo is running a smaller system with no heat issues. I can't imagine our monuting is that different.

To program the MM, turn it on, wait for the first beep, then pull full throttle until you hear the 4 beeps, then full reverse until 4 beeps, then neutral until 4 beeps and then it will beep again to tell you it's done. I never program mine by holding full throttle before I turn it on...always after the first beep, but before the double beep saying it's ready to go.

I've got virtually no airflow on mine. It's double side taped right behind the Rx box on the chassis.

I must be reading my manual wrong. Thanks for clearing that up.

If that's so, it sounds like it was overgeared. I don't think the slash is "big" enough to require a larger motor, but that's just me I guess. I've also found in the past that better batteries (i.e. ones that don't drop voltage as much) will run the system cooler, since you're not trying to suck the life out of the battery and make power with the current. Packs that maintain their voltage level seem to run cooler.

I took it out for a run on the 13. Temps are still not good on the motor. Speed control was 143, batteries at 140 (7 cell gp3300), motor(5700kv) was smoking at 180. This motor simply won't run in the slash well. Maybe try the 4600kv Unless you think 180 is acceptable for a 5 minute bash.

I'm really surprised the 5700 won't come down in temp. But, I do think the 4600 is better suited for the Slash.

I agree. :) How is your staying cooler? Different driving habits? Yours is smaller if I recal.

I'm running the 4600...that's why it's cooler than your 5700. :intello:

ahhh ha :rofl: that would explain it

How much top speed can I expect to loose if I swap to the 4600?

Mine is geared for 33mph on 2S lipo. You should get a little better speed with higher NiMh cell counts. However, IMO, 2S Lipo is the way to go.

The 4600 running on 3s but geared down to ~30mph should help things a bit. If you want to keep the 5700, I would gear down quite a bit if running on 3s. Just trying to lessen the motor/ESC load a little.

Temps on my 4600 in my Slash are fine on 2S geared at 33mph. I'm not sure why you would recommend gearing for less speed than that on 3S?!?

I was really hoping for the 3s. The few times I've had it out on the 9 cells it's been fun. So maybe the 4600 or VXL motor is the answer then. Both are cheap motors atleast. I'd really like about 50 MPH top speed. There's a few revos in the neighborhood I need to keep on top of.


I don't think there's a small enough pinion that would produce an acceptable top speed with this motor in this truck.

I geared it back up today to the 15, stuck a fan on the esc. I didn't check the temps again but will later today and report them back. The truck is real fun. Half my yard is sand, we've built a few sweeping dunes of sort, between that and the weeds it's like the desert.

ESC was cooler because of the fan, motor was at 180 again. If the ESC is cooler, that's good for me. If the motor burns out, I'll replace it. I'll deal with the temps again when I get the lipos in. As it stands now I get beat the snot out of my brushless slash. :mdr:

I didn't see it mentioned anywhere but what do you have the motor timing set at? If it is not at the lowest setting give that a try.

If you do end up cooking the motor you may want to try the velineon motor with your 3s lipos. You should be able to gear up to get more then enough speed to smoke the neighborhood revos with that setup.

I have the timing at the lowest setting.

fwiw I program my MM by holding full throttle before switching it on, never had a problem.

It seems strange that you dont get arming tones - they play through the motor, so it wouldnt have anything to do with caps.

That's what the manual said also. Maybe mine has issues? :neutral:

Yeah, it cant be that much different than setting it up in a rustler. I'd disable your punch control, double check your timing is disabled or set to lowest, and set your start power to high. I'm sure the 5700 is fine on it, maybe cut a hole in your body to get some airflow to the esc. Really you shouldn't have to gear that low. Maybe if you're running it through grass, but on hard dirt or pavement 17 or 18 should be more than low enough you'd think. I personally don't have a slash so I can't say. But it seems to me that the drivetrain is the same as a rustler and the weight shouldn't be more than a pound or two difference, there is no way a 5700 is not motor enough to push that around at a higher gear. Especially if the exalted titan wasn't overheating at stock gearing. Play with the castle link software settings, make sure you have the most recent firmware release and maybe borrow a 2s lipo from someone and see if you can nail this thing. Also mounting your esc behind your rx box probably isn't a good place for it, should keep those two as far apart as you can. Also check motor plugs, if there is any corrosion looking spots on any of them, clip them off and direct solder.

I just thought of the whole arming tone thing. If one of your motor plugs aren't making good contact, ie unplugged or crispy plug, it won't sing to you I've noticed.

I ran today for a short time and things seemed better. Perhaps this is all "user error" on my behalf. I'd hate to think I'm that stupid. I geared it back up and temps seemed better. I have no reasonable answer for this.

The arming tones are definetly funny though. Sometimes I get them, sometimes I don't.

They often change volume and sound depending on the car, or if you have the wheels on the ground or if your touching the motor (absorbing vibrations).

In my CRT they sound really funny, I think because its all alloy on alloy with a metal pinion/spur, it sounds like its all fuzzy haha. But yeah sometimes ive noticed they go really quiet too. kinda cool how it plays you tones like that i reckon :P

Well, like I mentioned, check the motor wires. When mine was giving me problems, it would act real funny like, not arming but still working or it would arm then it would run, then stop, jiggle wires or kick it, then it would run again, I had a seized up bullet connector on the white wire, the part that spins didnt spin and had black spots all over it. I chopped it, soldered it direct, worked better than ever. Then my car eventually started glitching real bad, chopped the other two off, the black one this time was seized, now it works like a champ.Or it could be a funky ESC.

If you sometimes get arming tones, and sometimes don't and you're running really hot sometimes and sometimes not.....you have a wiring problem, definitely. Pull on all of your bullet connectors to make sure the solder joints are still tight. Make sure all the connections are fully seated and clean. 1maxdude mentioned he saw black spots, definitely a sign of arcing. If you see any of the above, that's the source of your problem