2200 Combo running hot !
 

Here is my setup, 2200 mmm combo,gearing on mbx-5t is 46 and 14 pinion running 5s 35c pack with rulux 1\2 ups and lpr bowties.Temps after 5 mins were esc 98,batts were 95 and then the motor was 186? Checked it 3 more times to make sure and was fairly stunned. Way too hot it seemed.Looked over the drive train for binding and such,but everything was free.I just rebuilt this whole truggy ,diffs bearings and cvd's,new wheels and tires new batts and the mmm was run straight out of the box.Is my gearing wrong? Do I need to lower my settings for timing to low from normal? Kinda scared to run this anymore due to the heat. I thought this combo was gonna be much cooler running.Any suggestions are welcome.I wanna have some fun,but not worry about frying this bad boy.

Yes, set the liming to lowest, that may help. Also make sure all of your motor connections are tight. Have any other motors to try?

The gearing sounds fine. How was the performance when it was running? Anything binding? Is it possibly unloading letting the motor spin up too high? Gear mesh ok? Pinion secured well on the shaft?

Those are just some of the things I could think to check that could contribute to your motor getting that hot so quickly.

A buddy of mine was running his MBX5T with a Neu 2200kv, MGM 16018 and 6s2p A123 (around 5s lipo). His truggy must have been heavier than yours (Battery wheight around 900gr/almost 2lbs) and at the end he used a 13t pinion. During hot sommer days the ESC shut down due to thermaling and the motor reached up to 85°C/185°F. He used crimefighter tires also on rulux wheels.

Problem is the motor revs too high with 5s (around 40700rpm). A nitro motor revs between 30000-35000rpm. With a 14 pinion your gearing is 1:15,11 and without ballooning your top speed should be around 74km/h / 46mph. Way too fast for a truggy on a track and when pushed too hard temps will be high.

Your best bet is to decrease load on your motor and use smaller pinions. Cut holes in your body to increase airflow. I would start with a 12t pinion which should reduce speed somewhat above nitro truggy level.

I have an Mbx5 buggy converted with 36 60 medusa ,mmm same gearing and runs 40ish on 4s and is almost cold to touch after running for 10 mins.I have run the same 5s pack in that one too and it did get a little warm,but not that hot like the mmm combo did, different wheels and tires though,and of coarse,lighter.I need some more mod1 gears to try gearing up or down,kinda seems like it could be geared up with everythingelse being so cool and all,but I'll try both ways. I reset the timing to low and will give that a shot today and will try all that was suggested .If it continues to run hot,I might have to pull it and try a 70 or 80 can medusa,they seem to run very cool and strong.And yes the 2200 runs very well indeed,with the front end pulling up anytime you want to, real torque monster.I did do the diffs at 7k 10k 3k,not so sure this is right for a truggy with this kind of power,but turns and burns well enough,with the front unloading a little when you put full power to it.

Tried it with timeing set to low,and it cooled things down to 160.Next I'll try bigger pinion and smaller pinions,still lots of torque but slow top end,about 34mph.

40k rpm isn't too high for the Neu though [?]. Thought they were safe to 50k.........

160 isn't bad for temp. Play with your gearing and you should find the "sweet spot"

Thanks for the help guys,about to order some different sizes from Mike.I do have a 12 tooth I'll try that next.then a 15 and 16 too.I love these Truggy's!:yipi:

airflow - do you have a hole in the windscreen?

Ya I think these motors need some airflow around them. So have you been able to consistently get 160 with the timing low? or was that just a shorter run? I know the timing for me means about 1.5mph down for each one so if you went from normal to low you probably lost about 3mph which isnt a bad speed for those temps.

Yeah...my first guess would be to check the drivetrain and make sure there isn't any binding. Pinion mesh could be off too.

Running a nitro boby with cutouts in it.Only had time for 2 back to back runs today and both runs read pretty close to the same temp.Here's a couple pics.

put much heavier oil in the centre diff. i bet your centre diff is unloading and making the motor rev out harder that it should be, look for the front wheels panning.

I know a billion of my friends have complained about hot motors on their 3 diff cars, and every time it's because the centre diff unloads too easily and the motor revs super hard with minimal load on it.

I re-checked the drive train today for any binding,but all looks and feels well .As far as pinion mesh.I set it with a piece of paper between the two gears and loc tited it down,and it's really holding the mesh well.I'll re-examin all those things just to make sure though. Pulled up the castle link again and went thru it to make sure all was well there too.Gears from Mike should be comming soon.With temps down in the 160 range I won't be so afraid to test it for a longer period now.Building these up has been made pretty easy with all the niceity's being sold now from savvy companys like Castle and RC Monster....it's the tuning part that takes some skill to bring it together and really enjoy it all,and a gratefull appreciation for those with so much knowledge and experience. (oh yeah...and lots of cash !):lol:

Was thinking that might be a problem,especially with all this grunt and rpm with 5s the motor puts out.Thanks for briging that back to mind,definately will try something heavier...maybe 30k?

yeah 30k at least, maybe like 100k or higher even. I think team assoc. even make a 300k diff oil - probably a little extreme for a racer, but still viable in an MT.. The thing is with an electric motor you have peak torque at 0rpm, so when you're on and off the throttle it is much easier to unload the diff than with a nitro motor, that simply doesnt have the balls in that lower rpm range. Be weary that with heavier diff fluid, even though the diff can still unload, itll be a bit harder to, and will make it much easier to flip the truck if you're a bit too keen with the throttle :p

By using a 30k instead of a 10k diff oil in your center diff, more power will be channeled to the rear of your truggy which might lead to faster acceleration (wheelies might become an issue though). This can only be achieved with more power put to the ground which equals to higher peak Amp draw which normaly translates to more heat.

On the other side you will apply throttle more gently as the car is likely to wheelie. Long story short it really depends on your throttle management how hot your motor gets. My eagletree logs showed higher amp peaks with higher diff oil in the centerdiff when using full power. But with lighter centerdiff oil you might constantly trying to use full power (more full throttle) which could also lead to a hotter motor, eventhough peak amps are lower.

I wouldn't say a motor runs hotter only due to the fact the center diff is too loose. It's a combination of a lot of variables.

I use 10k in my truggy center diff. It can unload if I make aggressive stabs at the throttle(and also heat up), but heavier oil negatively affects handling on my track(loose and bumpy). All the "possible issues" discussed here can impact heat, but a smooth throttle finger will make a huge difference as well. When I am on the track, I hardly spin a tire. My setup is a little different(1515/2.5d on 5s), so the power isn't as aggressive, but I also use a mild throttle curve to help with low end control. If i am tooling around and making sharp, aggressive stabs at the throttle, I can heat things up.

"aggressive stabs at the throttle".... no one here does that :lol:

I think the castle link programming and I will play around for a while.

mike can you post a pic of your throtle curve so we can see it, thanks

For the general throttle curve - grab the curve at 50% and pull it down to 40%. This is where i usually start - softens the low end nicely and smoothly transitions to high speed. :)

Ran my Mbx5 buggy and truggy just to compare them with the two different setups.The buggy is a 36-60 on 4s and it kills the truggy in speed and handling with the truggy running on 5s 2200 combo.Heck the buggy has 7k-50k-3k setup for fluids and runs the same gearing except for the tire size factor.I'm going to put a 70 can medusa in the truggy without changing anything else just to satisfy my suspicion about this 2200.Pretty much tried everything else.Put a 12 tooth pinion on there and made it nice and quick...and slow on the top end,but actually got hotter,up to 178.Settings on the throttle curve are like Mikes and it really mellows it out till you pull the trigger harder.I did the curve to my buggy and it really makes a difference in driveability.You can adjust you radio settings also to get similar results.Put some 30k in the center last night and will run it again with the 14 tooth to check the unloading situation.Putting all new drive axels and cvd's in cause they are a little bit warped.

I'm curious how the medusa does

mmm medusa
 

I'm thinking the medusa+ mmm esc is one bad azz setup.My buggy on that combo is AWESOME on 4s .No b.s.

I feel this. Very well put. You obvioudly have a grasp of what is real and what is spoken sir.:great: And thanks Sammus,your on track too,appreaciated.!

The kv of the combo motors are to high in my opinion, Mike tells me to run a 2.5d 1700kv in my truggy with 5s. he says thats the perfect combo for these truggys. I dont know why castle wants us to run 50-60,000 rpm's...I just dont get it.

Cause very very few people will be running something other than 4s.

We are coming out with both 1800Kv and 1500Kv motors -- watch for 'em.

Patrick

Well, that is more like what we need, I can't wait! Right on Patrick!

I've been watching all day and nothing so far. My boss is gonna start asking questions pretty soon. :no:

:lol:

Marketing strategy...........:whip:

Patrick,
Do you know how far out these 1800kv motors are, and if they will be available in the combo? 6s bashing sounds perfect to me...

Thank You Sir.
Sean :smile:

I have a Xray Xt8 Truggyand have mikes conversion kit, I am just waiting for my combo to get here. its a mmm/2650kv and i was going to run it on 4c lipo.
anyone have any advise, cautions, or 'hold the phone' Ideas?
Thank you,

4c lipo?? I hope you are running 20Ah cells! :wink:

AH.... I am not sure my local hobby store told me this setup was recomended by castle. but i dont know the specifics of the battery that was ordered for me. its in a hard case if that means anything??:whistle:
What do i need to know about the batterys? sorry i am fairly new to the electric thing. but am learning as we speak (reading tooo many posts):tongue:

Probably means 4s lipo, give the newbs a break Brian.

Think ima just say the heck with 5s and run it on a fat 4s pack,..seems to be the way to go with a 2200 combo anyways,plus it will live longer.Then scoop up an 1800 later and convert that Mutilator into the Defacator !

Sorry, I thought it was simply a typo and was giving you a bit of crap. "C" refers to the amount of current a pack can deliver and a multiplier of the capacity. So, a 15C 5000mAh battery can deliver 75A (15 X 5000mAh). When we talk about the number of series cells, we use "S". You were talking about a 4S pack. Incidentally, some packs also have a "P" value, which is the number of parallel cells. Like in 5s2p has a total of 10 cells, 5 series connected sets of 2 parallel cells.

No offense man, just some harmless fun.

lol, yeah, I shoulda looked at the post count. :oops:

Yes.do tell....