MMM v3 flameout - 2nd drive EVER??? :(
 

Hi All,

I am gutted, this is the second drive of my 8ight-T and the MMM has burst into flames about 5 mins into my second drive EVER?

I test drove my car this morning and checked temps twice to make sure everything was running as expected, temps all OK (motor ~150 at hotest spot, ESC & lipo ~ 100), documented in my thread in the Truggy forum.

I took the car back out this afternoon and after about 5 mins of driving, getting the feel of it, and the car stops, then smoke and flames. I freak and run to pull the car apart thinking the lipo's puffing (as all temps were OK this morning) and check this out.....

battery wire has completely un-soldered from the ESC.....something blown in the ESC????

http://i520.photobucket.com/albums/w...t/P1040529.jpg

http://i520.photobucket.com/albums/w...t/P1040530.jpg

My setup was MMM 2200 combo, 14/48, Neu 5s1p 6500mah Lipo

I've sent an email off to castle support & repair as I'm in Australia, otherwise I would ring them. Is this a common thing?? I've been reading for a long time prior to my build and beleived I had a fairly conservative setup with a high quality lipo and all would be OK???

bummer dude dont feel like your the only one. i had a v2 that lasted long enough to turn it on and set the car down on the floor before it died. yes its frustrating but castle is great at taking care of their customers who have legitimate problems. setup sounds good to me but how long does it take for you to hit those temps? just to be safe i would check for binding in the driveline and all your connections good luck!

You are not alone. I had one burst into flames and the cables desoldered just like that. It happened within the first 5 min my truggy's maiden run.

Hmm.

Setup is for ~47mph, fairly fast but not unreasonable by any means.

I agree, check for any binding in the drive line and gear mesh, but this looks like another random failure for no particular reason...

I hit those recorded temps @ the end of the 6500mah pack. The only temp that seems a little high is the motor but I got different temp readings all the way along the can in the range of 50 (front of can) -65 celcius (rear of can) which is 133-149F. Wasn't quite sure which reading to use, so used the highest and also used Castle's recommendation of "Never allow the motor to exceed 170F during runs"

Thanks Neil, realise it was geared for around 47mph but also thought that if temps were in check then this wasn't an issue. No binding in the gear mesh from engine to centre diff, very aware of this process after owning a Rustler VXL for 18 months. I'm not sure how hard it should be to turn over the front and rear diffs from the centre diff of a truggy however, I have no other car to reference here?

Hi mate,

Was yours replaced under warranty and how was the next one your received?

With the pinion moved away from the spur, you should be able to roll the truck along back & forth in a smooth motion, no jerkyness or sudden stopping when you let go- it should roll to a gentle stop if pushed across a hard floor for example.

Excellent thanks for explaining that , yep does that no problems. I though I might have to like manually rotate the spur in the centre diff and guage it like that. I bought the truggy second hand but based on the bottom of the chasis it looks like it had like a single race meet in it. I pulled all the diff's apart and inspected all gearing, then refilled with diff oil (7/30/5).

cheers

yeah i had mine die this weekend too. bad week for mmm's

what went down with your's emaxxnitro?

same thing

sad


my buddys v2 died last nite and took his bran new lipo with it

How many cells were you guys running when it smoked?

I'm starting to think that over 4s lipo the MMM is simply a http://i212.photobucket.com/albums/c...a5b/images.jpg

Don't get me wrong, great unit if and when it works, but we're now at the stage where you need to bring a fire blanket and extinguisher with you just to run your r/c

Any other toy on the market would have consumer protection all over it like a rash.

I've had 2 * Sidewinders, 5* Mamba Max's all have been brilliant, but I'm nervous about running my Flux, even on 4s!

Although think yourself lucky compared to this one:

http://i212.photobucket.com/albums/c...results002.jpg

Thats not an MMM though, looks like a Castle boat or plane controller that was pushed too hard :smile:

lol, good catch. Judging by the heatsink config and the number of layers, I'd say that was either a Phoenix HV85 or one of the regular Phoenix ESCs.

That car is crispy...
FWIW my MMM on 6s has been nothing but perfect. The switch failed but who cares.

I agree my SideWinder was awsome on 2S. I've got a response from Castle which is really good offering to pre-ship me a unit prior to sending the smoked one back, so that's one positive.

I have however posed some genuine concerns to them regarding the unit as a whole which I shall await their response on.

Whats the likelyhood of this happening over and over again (This unit has
had 20 mins runtime on it)?

Can the Monster ESC reliably run over 4S Lipo (I thought considering its
rating for 6S that my 5S choice was concervative and a good medium ground)?

Is using ESC braking a potential issue in these uinits?

Is there potettial that the ESC smoking has damaged my receiver, servo's or
the engine as looking at the case of the ESC, there been a large spike of
power to cause that flash/burn and melt the case?

lets wait and see ...?.....?......?

Brian - pulled this comment from the other thred running at the moment regarding MMM fire:

So are you guys saying that the EMF is causing the ESC's to fail prematurely? If so, should I be running mechanical brakes on 5s 6500mah Lipo's? If so, how do you assign reverse on a Spektrum DX2 to actuate the brake servo??? I'm all for it if it will stop the Monster failing again? Or are you recommending not running over 4S?

5 cell with a ccbec

when we all bought our v2's castle was still calling the bulletproof on 6cell so we went 5 cell so have alittle breathing room

I wouldn't call what I said "official", it's just my tendency to not run things to the max specs. I routinely run both my MMM systems on 5s with motor brakes and no problems so far.

I only run my 11lb truggy on 5s 5000mah zippy h 20 - 30c and have not had a single problem 13t 62t pinion spur.

I run my Savage Flux on no more than 4s, above that, and with such a heavy truck, I don't trust the ESC.

Thats fine mate, I know it can't be catergorised "official", but I know your a well respected member of the forum with a wealth of practical knowledge and I value your opinion.

I'm somewhat trying to get my head around why after doing all the reading, setting up my car how I considered "best practice", taking temps at multiple stages of the first run, I still blow the ESC in like 20 mins???

Would you consider my setup excessive or borderline or is it just "one of those things"??

If I gear down to 13/48 won't that just give me more torque and make the motor hotter?

Losi 8ight-T
MMM 2200Kv combo
14/48 gearing
Neu Energy 5S 6500mah Lipo

thanks

From what I read in the MGM article, even 5s may push the volts a bit too high under breaking, they used the example of a 6s set up on an 8s ESC, maybe we need such a high window such as run at 2/3 of rated capacity. IE run a MM at 2s not 3s and a MMM at 4s not 6s. They will run at 6s, sure, but the risk of failure especially under brakes would obviously be higher.

i run all my mmm on 6 cell lipo no issue at all:whip:i kill 3 units but my issue was my 5 months old maxscrap 14,8 pack<<<