MMP overheating

[Turtlejon]

So my MMP is just overheating too much to be fun on longer trails...
I'm running a pro4hd 2500 kv, 3s, ccbec, 8 lb. wraith, 11/56 gearing, all metal gears and driveline, RR slipper, 2.2 swampers, no weights in wheels, smart sense. It was waterproofed by Holmes, which I'm sure doesn't help. Everything in the drive line seems to move easily. It lasts about an hour to an hour and a half then cuts off. If I wait a few minutes, it works again for a few more minutes. I tend to mix up a few minutes of speedy rock bouncing in between sections of steep technical crawling.
I may be able to lower the gearing a tooth or 2, but that was the lowest ratio I could fit under the gear case with parts that were in stock at the LHS. The 5mm shaft of the Pro4HD makes finding pinions tricky, the 11 was the smallest RR had. It seems the MMP has only a 65A continuous /120A peak current, which seems kind of low for this use.
Any suggestions of things to check or change? I'd prefer not to buy an RX8 or anything like that if I didn't have to.

[351Beno]

You got a fan on that thing? If so and everything turns free with no binding maybe you need a Mamba monster x.

[Turtlejon]

Y'all think MMX is better than RX8 gen2? It's sure quite a bit less expensive...

[Olle P]

Originally Posted by Turtlejon

... It seems the MMP has only a 65A continuous /120A peak current, which seems kind of low for this use.

The 65A continuous is NOT low. Not by a longshot! (Your average current draw is (<)1C, and I bet you're not running 60Ah batteries.)
The 120A peak rating might be a restricting factor while "bouncing on rocks", but not for heating and not something that should take an hour of driving to kick in.
Have you measured the drawn current?

Do you have the ESC in the open or inside the electronics box?
Good ventilation is required for cooling, you know...

[redsawacs]

I bet it is because you're using a 550 motor but I could be wrong. Most people use the rx8 with 550 motors which leads me to believe the mmp isn't strong enough to run it auccessfully.

[Turtlejon]

Yeah, the MMP has tons of airflow, I am using decent quality batteries, usually gens-ace or vant. I suspect it just can't handle the pro4hd.

[SwampDawg]

Sidewinder3 could do it?
3s capable and has drag brakes but isnt sensored if you run brushless??

Caution!! R/C is highly addictive!!

[dna4engr]

Originally Posted by Turtlejon

Yeah, the MMP has tons of airflow, I am using decent quality batteries, usually gens-ace or vant. I suspect it just can't handle the pro4hd.

I run a traxxas ET3S (Traxxas branded MMP, that I unlocked and reflashed with MMP software).
It's in my Yeti wit a 3500kv Pro4HD. I don't remember how it's geared, but considering it's a Yeti, it's much higher than your rig. Also around 8lbs. Mine much prefers full out throttle than slow crawling. However, in either case it does have the cooling fan turn on occasionally. This esc is waterproofed BTW (by me, not someone else but i use conformal coating just like HH does). I only run on 2S due to the gearing. On 3S it gets super hot but never browns out. The only time this rig has stalled at all is when the batteries are getting low and I pin full throttle on a high traction surface. Even then, it's only a momentary thing until it launches. I attribute that to the battery.

My buddy runs an MMP with a redline in his wraith based rig at 8lbs with a 2 speed trans on 3S. In high gear if he pins the throttle, it does the same thing my rig does when the batts are low.

Being that you get an hour of run time before it "browns" out. I'm not thinking it's the ESC. I would actually target the batteries first. Do you have any 2S packs you can try or a new 3S pack from a friend. Just to rule it out.

Also, check your firmware on the ESC in castle link. I run and old version of firmware that only turns the fan on when it gets hot. The newer versions all turn the fan on immediately and keep it running. If your fan isn't turning on, then there may be an issue.

If you can pick up a cheap temp gun, that would be a good thing to have at the ready when it browns out. Check the motor case temp as soon as you can. Also check the esc. It's difficult due to the fan and all. Everything should be 160* or less. If you're way over that (like 200+) you are definitely taxing the esc too much.

Also, if you have a volt meter, check the batt as soon as the truck browns out. If the voltage is down in the 10-10.5v range, it could be triggering the LVD but your batt rebounds enough to run for a few minutes longer.

No question an RX8 or MMX would resolve any overloading issues on the ESC. However, the ESC won't fix degrading batteries.

[JohnRobHolmes]

You sure your batteries just aren't dead after an hour and a half? Even if it is hot, it would need to boil water off it before overheating actually occurs. Is it over 200f?


The waterproofing doesn't hurt cooling on the MMP. The heatsink isn't affected at all.

[Turtlejon]

Yeah, the first thing I figured was empty battery, so I tried fresh ones. I will try a brand new battery, as these are a year old, or so. They seem fine in other cars... The motor seemed warm to the touch, but not hot at all. The esc wasn't too hot where I could touch it, but I couldn't easily get in on it. I updated the firmware and I'll try again. I'm sure the firmware was somewhat recent, within 6-8 months.

[yotawheeler]

Originally Posted by JohnRobHolmes

You sure your batteries just aren't dead after an hour and a half? Even if it is hot, it would need to boil water off it before overheating actually occurs. Is it over 200f?


The waterproofing doesn't hurt cooling on the MMP. The heatsink isn't affected at all.

I have this same problem. I was running the hh trail master & 550 puller pro xl. If I crawled slow through tough sections it would stop after like 10-15 min. Let it sit for a moment and it will work again, as long as I didn't crawl slow it would be fine. Anyway now I have a brushed setup in it. Gearing is 80/20 same as it's always been, if I crawl real slow threw tough twisty stuff the motor gets really hot, can smell it. Gone threw a 55t a 40 and now I have a Titan 550, truck will not crawl threw technical stuff without getting hot. Everything spin freely. Idk definitely frustrating.

[JatoTheRipper]

Originally Posted by Turtlejon

Y'all think MMX is better than RX8 gen2? It's sure quite a bit less expensive...

Heck no. Tekin is much better than Castle in my experience.

But, like others have said, remove the motor and see if there is any binding in your driveline.

[WHITE-TRASH]

Originally Posted by yotawheeler

I have this same problem. I was running the hh trail master & 550 puller pro xl. If I crawled slow through tough sections it would stop after like 10-15 min. Let it sit for a moment and it will work again, as long as I didn't crawl slow it would be fine. Anyway now I have a brushed setup in it. Gearing is 80/20 same as it's always been, if I crawl real slow threw tough twisty stuff the motor gets really hot, can smell it. Gone threw a 55t a 40 and now I have a Titan 550, truck will not crawl threw technical stuff without getting hot. Everything spin freely. Idk definitely frustrating.

4:1 gearing and you're surprised it's getting hot while crawling.

[Soldat Vaillant]

Originally Posted by yotawheeler

I have this same problem. I was running the hh trail master & 550 puller pro xl. If I crawled slow through tough sections it would stop after like 10-15 min. Let it sit for a moment and it will work again, as long as I didn't crawl slow it would be fine. Anyway now I have a brushed setup in it. Gearing is 80/20 same as it's always been, if I crawl real slow threw tough twisty stuff the motor gets really hot, can smell it. Gone threw a 55t a 40 and now I have a Titan 550, truck will not crawl threw technical stuff without getting hot. Everything spin freely. Idk definitely frustrating.

You need to drop your gear ratio, get the motor up to an RPM where it's building a little more power/torque at your crawling speeds.

[yotawheeler]

It was 88-17 . My mistake. The 17 was as low as I could find for the 5mm shaft. 80/20 is what my scorpion runs with no problems at all

[yotawheeler]

Would 64 / 11 work? That seems to be as low as I can find in 32 p with a 5mm pinion shaft.

[WHITE-TRASH]

I've seen 10 tooth 5mm pinions but I have no memory of who made them.


64 tooth won't likely clear the driveline but 60 should without issue.

[Soldat Vaillant]

Originally Posted by yotawheeler

Would 64 / 11 work? That seems to be as low as I can find in 32 p with a 5mm pinion shaft.

That would be 5.818 down from 5.176 and should help, if that's not enough you many need to drop the front and rear axle ratio as well.

Also double check your gear mesh, if it's too tight it can heat up the motor.

Set Your Gear Mesh for Spur and Pinion

Hot Racing has 32 pitch 5mm bore pinions down to 9-tooth but you may have to space the motor back or the spur gear forward to use them.

http://www.ebay.com/itm/Hot-Racing-9...kAAOSwDuJWw-FH

[Soldat Vaillant]

Actually Hot Racing has them down to 8 tooth for the Traxxas Summit.

Hot Racing Traxxas Summit RC Car upgrades and Hop-ups

[yotawheeler]

Originally Posted by Soldat Vaillant

That would be 5.818 down from 5.176 and should help, if that's not enough you many need to drop the front and rear axle ratio as well.

Also double check your gear mesh, if it's too tight it can heat up the motor.

Set Your Gear Mesh for Spur and Pinion

Hot Racing has 32 pitch 5mm bore pinions down to 9-tooth but you may have to space the motor back or the spur gear forward to use them.

Hot Racing 9T Steel 32P Pinion Gear 5mm Bore NSG3209 | eBay

gear mesh is not the issue. Thanks though. I have to check and see what I replaced the ring and pinions with, possibly I went higher with those by mistake maybe?