CC MM's..arnt so awesome.

Good times Good times!

If you guys have read my CC BEC thread, then you'll know where this one is headed. Hah!

Anyways after blowing two CC BECS.. i went and bought another BEC (not a CC one this time thank God). Anyways, I hooked everything up and powered on the truck. Running 2 x fairly weak 6 cell NIMH's at the time (better safe than sorry..dont wanna blow those LIPO's of mine).

The truck moved, but it was weird. It was weak (more so than normal, when running NIMHs). Also, it was glitchy..not radio interference (running a Futaba 3PM 2.4ghz) but with the throttle; it would act as if you held onto the throttle for longer than you actually did.
i.e throttle for 2 secs, truck accelerates for 2.5 seconds.

Anyways, at this stage I thought hmm "must be some dodgy soldering"..so I took the thing back home, took everything apart and resoldered everything. After I finished, I took the truck back to the park.

Same sort of thing...weird!

Anyways, gave it a bit more throttle and it proceeded to accelerate by itself for about 2-3 seconds (good thing there was no one around). Then BAM!

FFFFFIIIRRREEEEEEEEEEEEEEEEEE.. smoke was POURING out from the truck. I started running towards it and could see the little fire that was inside.
Ripped off the body (4 body pins still attached btw) and blew the fire out.

Im kinda losing faith in CC at this stage :(. I still need to call them up about the blown CCBECS. I guess this mamba can go for a nice ride to the states as well.
Argh. Ill be out of commission for a good few months because of this. Not happy. Not happy at all.

[plettenbergs]

not sure, bit i think it is damaged!

[MTBikerTim]

It is possible that the MM was faulty but from what you described it is quite possible your motor is the problem.

[sikeston34m]

Ok, so there have been several things go poof on your truck.

Your BEC. This is used to power your receiver and your servos.

Your MM ESC.

Your truck remaining under power even after you let off the throttle, points toward your receiver. The ESC isn't just going to do that on it's own, since it receives it's "instructions" via pulse width modulation from the receiver.

Check your Servos. If you have one that is drawing way too many amps, this can overheat things inside of and damage the receiver. It can also take out things like BEC's.

I myself have used a number of MM ESC's and they all have performed flawlessly.

The receiver is the Futaba 2.4Ghz one, and has worked fine with the stock electronics (Traxxas EVX-2 and the 2 x Traxxas Servos) for extended periods of time (I was running a stock E-Revo for a good 2 months).

I will put the receiver into my E-Firestorm setup and see how it all goes tomorrow. Im sure it'll be fine though =)

I had a ccbec and mm fail at the same time,took out the servos,but the receiver seems fine.I'm wondering if there is any way that maybe the BEC sent some sort of reverse current through the system.Feeding + through the negative and dead shorting the esc.Probably not likely,but when you lose everything at once you start shooting in the dark.

[Arct1k]

I think this is more than likely setup related rather than the CC. It was probably your "weak batteries" - They were unable to sustain the current to the ESC and the voltage dipped. This probably caused current ripple that the caps could absorb and you ended up toasting your esc.

I'd also bet that this was in a E-revo based on your sig. The MM was designed to run on 3s max on 1/10th scale. We all take a risk and run mods to get it to run on 1/8th scale - don't see a mention of extra caps etc.

I would look at your own setup first.

you dont really need caps on the mm, extra that is, i have the mm on my x1 truggy with a 1y, and thing is just flawless, all i have is a fan on it, never hits 140, but yea. something is up with this, blowing 5 components in a little time?

[Arct1k]

Personaly I toasted 2 MM's and then started adding an extra 2700uf 25v cap to them - Since then no issues on 4 controllers on 4-5s.

PS I hope you own up and send in the $50 for running out of spec ;)

yea i run one on both buggy and truggy, i have seen people have issues, i guess im lucky, been going over a year on my truggy esc, buggy is new since i crushed it lol

[hootie7159]

i believe its setup related as well....i had a MM as well but did the fan mod and added a cap...it began to do the same exact thing that your did except when i was going low speed throttle it stuttered then then "POP!" smoke came out from under the body...luckily that "POP!" was a blown $10 capacitor ..... this whole problem , as i eventually found out" was related to my gearing....it was in an overgeared e-revo on 5s.....so i changed the gearing, added another cap, and my MM has outlasted my revo and now is a back up to my fully functioning MMMv1 and MMMv2....i;ve also owned 5 cc bec for about a year and they have all worked flawlessly...guess you got a bad batch or something ...

[Bernie Wolfard]

Weak batteries kill more ESCS than overcurrent. You simply cannot use 'weak' batteries with a high power system without damage. Look up 'Ripple Current' or 'Current Ripple.'

Bernie

[BrianG]

Originally Posted by Bernie Wolfard

Weak batteries kill more ESCS than overcurrent. You simply cannot use 'weak' batteries with a high power system without damage. Look up 'Ripple Current' or 'Current Ripple.'

Bernie

Which is why many people find that adding an extra cap or two helps a lot. I understand what ripple current is and how too much can cause excessive cap temps and cause failure, but does it cause other problems within the ESC?

[George16]

Originally Posted by BrianG

I understand what ripple current is and how too much can cause excessive cap temps and cause failure, but does it cause other problems within the ESC?

I would like to know that also.

The MM system that blew up on me was running fine in my older E-Maxx 3905 (for about a month on NIMH's before I upgraded to LIPOS). The MM was purchased in January of this year and was in the Emaxx for a good 6-7 months. I have run NIMHs on this system without issue on many an occasion.

My friend had the same setup (8XL+MM) running on 2 x Maxamps 10,000's and the EXACT same thing happened to him. This is why Im skeptical when you guys are pointing at the batteries. The NIMH's although they cant sustain high current draw, can surely power the truck without blowing up things(the Nimhs were pretty much fully charged at the time..by "fairly weak" I was referring to the batteries themselves (venom 3000's) not the fact that they were nearly dead). The basis for my argument is the fact that Ive run these NIMH's many times without issue. I could be wrong though and it was the batteries but why would they do this to me NOW instead of when I first connected them in?
All these problems (blown CCBECS, firey MM's) hit all in the space of less than a week. Prior to this, life was peachy.

I was NOT at full throttle at the time anyways, was about 1/2 - 3/4 throttle. I merely pressed the throttle, the car jerked for a bit and then proceeded to go full throttle by itself (which wasn't very quick anyways) and then finish itself off in a ball of fire.

Also Hootie : my E-revo is pretty conservatively geared (18/68) and Ive got a fan on it too!..it'd be good to note that the fan is still in tip top condition!

Arkt1k : Of course, money isn't really a concern here. More so the fact that things keep blowing up on me :(. I just want a setup that works. Ive got the Castle Combo (2200kv) on order but it's still gonna be a while before it hits store shelves.