1515 2200kv heat issues in buggy

[KniteWulfe]

I have been running a mmm 2200 combo in my mp9e for about a month total now and have been in a constant battle with heat issues. Ever since I got it it has been a struggle to keep temps under 200. I geared it as high as possible and got some great runtimes but it actually seems to just make things worse.

I have checked gear mesh, drivetrain for binding, tried a bunch of different batteries, cut cooling holes in my body, set timing to 0 and even replaced the motor and esc. I'm stumped as are the guys at the track and castle phone support.

Right now I have a 14t pinion and 46 spur which puts my top speed just over 40mph and it comes off the track at around 180-190, after about 15 minutes with a 4500mah 30c 4s pack. I still can't get through my 5200mah packs without getting dangerously close to 200. I've tried as small as a 12t (geared for 32 mph) pinion and I still get temps of almost 200 after just 15 minutes.

Anyone have any ideas? I'm getting desperate, I bought this motor hoping to keep temps low...

I ordered an eagletree and a new temp gun, mine did seem to read about 10* hot compared to my friend's. Also replacing all of my bearings and rebuilding my diffs today just in case.

Ambient temps are about 75 now, but the really high temps were in 80-90* weather.

[nuz69]

Hello
There is an issue indeed, my mp7.5 with 14/46 ratio and 1515 2200Kv on 4S barely breaks 100-105°F... If you have the same problem with different motors and ESC it comes from somewhere in the vehicle. Is your motor mount correctly installed ? There is black plastic under the motor, maybe it strains your motor ?? Give us some closed photos so we can see if the motor is well installed.
Or like you said maybe your temp gun, so measure the temp with your friends temp gun.

[KniteWulfe]

Last weekend I took the readings with my friend's temp gun and it was at 175 on the end-bell and 150-155 on the sides. Ambient temp was 75 and windy. Better, but the lower ambient temp I'm sure had something to do with it. The weekend before, track temps were like 120 degrees.

I was under the same assumption, that the vehicle was the issue, but I cannot find any binding at all, it is very smooth. When I let off the throttle it coasts as easily as can be expected from a notchy 4-pole motor. I am going through the drive-train and rebuilding though just as a precaution. My motor mount is installed properly, and I put a piece of foam rubber on the black plastic thing to cradle the motor better.

As I was typing this I was inspecting the mount and the black plastic brace thing. I pulled the motor and noticed quite a bit of wear on the underside of the end of the can, it looks like the brace was doing nothing for the motor and it was slapping the chassis. I wonder if you are on to something and the pinion is binding under flex causing added heat. I'll test the motor in another vehicle this weekend and see how it temps with the same gearing. It would have to be something that only happens under throttle or under flex causing binding if the car is the issue.

[nuz69]

Anyway I don't like the kyosho 2 pieces mount, I replaced it with the RCMonster one, and the spur is far better close to the motor, meaning less strain on the front bearing. But with the kyosho mount I had'nt this kind of high temps. There is probably something with the motor mount

[KniteWulfe]

It's something to look into anyway. I'm trying to eliminate any possibility. I really like the two piece mount for convenience though, I haven't really looked at the rcmonster one.

[KniteWulfe]

So, I logged the issue with my eagletree today but now I'm even more confused.

I used 14/46 gearing with a 4500mah 30c turnigy 4s pack. The temp got up to 140 in a few minutes and stayed there until 16 minutes. Then suddenly the temp started to climb and actually peaked just over 200 at about the 23 minute mark. The esc temp stayed around 150-155 and didnt climb. My peak amps were just over 110 and, and voltage drops were pretty consistent all the way to lvc. The graph didn't show anything out of the ordinary aside from the temp at that point. My second graph was the same, but with a second identical battery. Unfortunately the guy who's laptop i was using left before i could copy it to my memory stick so I'll have to wait to post the graph.

What could possibly cause the temp to shoot up so high so fast like that? Is it possible for the battery to somehow cause that without effecting the esc?

Oh forgot to mention my 1800kv 1512 had a much more linear temperature climb, maxing at about 180 with a 17/46 gearing and the same battery. No abnormal spike at all. runtime was quite a bit less though, only about 16 minutes vs 25 from the 1515 2200.

[KniteWulfe]

Ok, couldn't get the chart from yesterday, but... I logged some mopre runs today, 1st with a 14T and 2nd with a 16T pinion. I put a huge heatsink and fan on to save my motor and set the LVC to 3.4.

Now after looking at these charts it seems that the battery is complete junk! I think I got about 10 runs out of this pack. All of my turnigy packs are having the same symptoms, losing power and cogging, and hitting LVC after a short time. Is this what has been causing my heat issues all along?

[sikeston34m]

Originally Posted by KniteWulfe

Ok, couldn't get the chart from yesterday, but... I logged some mopre runs today, 1st with a 14T and 2nd with a 16T pinion. I put a huge heatsink and fan on to save my motor and set the LVC to 3.4.

Now after looking at these charts it seems that the battery is complete junk! I think I got about 10 runs out of this pack. All of my turnigy packs are having the same symptoms, losing power and cogging, and hitting LVC after a short time. Is this what has been causing my heat issues all along?

IMO, the charts don't look horrible in terms of the packs performance, but...........

When is it cogging? on startup? It cogs more in the 16 tooth, than the 14 tooth, doesn't it?

What top speed are you geared for?

Cogging itself creates HUGE amounts of heat VERY quickly. Cogging also will suck the juice out of the pack very quickly.

What are your ESC settings?

I would look at addressing the cogging issue itself, then log some more runs. You have to get the cogging stopped.

The cogging isn't necessarily the Lipo.

Cogging is usually the result of improper gearing or improper ESC settings.

[KniteWulfe]

Start power low, 0 timing, no punch. Never cogs until about halfway through the pack, on startup, and gets much worse as the pack gets low. Did you see the voltage dips on the 2200 16t graph? I hit the 3.4v Lvc after just 1400 mah. Gearing is for about 39 on the 14t pinion or 45 on the 16.

Also keep in mind I had a huge heatsink and fan otherwise my temps will hit over 200 even on the 14t. The temp spike happens right around halfway through the pack when the power suddenly drops and cogging starts. It's the same for both of my turnigy 4500 30c packs and the pairs 5200 30c packs. In fact it is worse with the 5200s. It didn't cog at all when the packs were new, and didn't have the power loss or other symptoms but the heat. It didn't even cog with the 17t at first.

I rebuilt the diffs and changed the bearings, and checked and triple checked the drivetrain for any signs of binding.

Anyway I've got over $400 worth of thunderpower packs on the way. If they don't help the issue at least I'll save a bunch of weight and eliminate that possibility.

[pinkpanda3310]

Originally Posted by KniteWulfe

It's the same for both of my turnigy 4500 30c packs and the pairs 5200 30c packs. In fact it is worse with the 5200s.

I notice on those graphs that the issue arises when the temp gets to 125-130. Your larger mah packs probably help to heat the motor just that little bit quicker.

I would imagine the esc would be getting fluctuations of temp at the same point but harder to notice if you are just using a gun and that's roughly when the fan kicks in.

Given it happens to any motor but the issue arises when the motor gets to a certain temp, one might assume mount is not integral at those temps. However, the car still rolls freely with no binding. Does it roll freely in reverse? I ask because that would be the direction of pressure on the drivetrain under acceleration.

[pinkpanda3310]

Originally Posted by KniteWulfe

Oh forgot to mention my 1800kv 1512 had a much more linear temperature climb, maxing at about 180 with a 17/46 gearing and the same battery. No abnormal spike at all. runtime was quite a bit less though, only about 16 minutes vs 25 from the 1515 2200.

Ah, missed this bit. So it is not happening to every motor. The first couple of times you ran the 1515 did it get excessively hot? Is it possible you demagged the rotor just a little, so the cogging happens at the higher temp range? Particularly in the middle or at the end of a run when there is less voltage to feed the system.

The 1515 would be more efficient as it is a longer motor which would explain some of the runtime difference, but I don't know if that is the complete story. Do you drive differently with the two motors? eg- light on the finger for the 1515 because of more torque.

[pinkpanda3310]

Just read your thread over at rctech. Someone mention high reving motors get hot.

Have you thought about running 3s just as an experiment?

[KniteWulfe]

I'm a little lighter on the throttle on the 1515. These graphs were with the LVC set to 3.4. Set to 3.2 I was getting 24-26 minutes on the 2200.

If the 1515 was damaged by heat, it wouldn't make sense. What would have caused the initial heat problem, which was consistent with the heat problem on my last 2200?

I have a conversion on the way for my mbx5r so i can compare graphs between the different vehicles, and isolate it as an electronics issue for sure.

[KniteWulfe]

no i haven't tried 3s yet.

[nuz69]

Firmware, what firmware are you using ? Try to back the firmware to 1.24 or 1.24beta, the most recent firmware give some problems to certain people, especially cogging at start-up...