MMM problems and wish list

[GriffinRU]

Hello gentleman’s,
I noticed (was out for some time) you have budzillion posts about MMM...
Can you help me out with creating a list of knowing problems, so I can take a close look at ESC itself and check what can be done to improve it or else.

Finally I've got my MMM and I took it apart and so, far I was left with polar opinion on new design. CC probably worked hard to make it difficult to repair, but not impossible. And I am not sure how this one can be more powerful (ignore 6S support for a split second) then mod1 MM (smaller form factor).

I am also would be happy to obtain failed units, for new hybrid ESC (MM FET's board plus MMM brains).
Looking forward for your feedback,

[lutach]

I'll be watching this.

[snellemin]

MMM is barely out and mods are allready been talked about. This is great man. I'll be watching this as well.

[BrianG]

Artur, I'm sure you've seen that the major issue so far is a failure of the BEC IC in some ESCs. There was apparently a bad batch of components to blame. Then, the fans don't seem to be lasting long.

The MMM is already a 200A controller. The only thing that would make this great would be higher voltage, but that wouldn't be near cost-effective since it seems like a mojor replacement of components would be needed.

Aside from the switching BEC unit and lack of USB port on the MMM, what would be the advantage of switching brains boards from the two ESCs?

[GriffinRU]

Originally Posted by BrianG

Artur, I'm sure you've seen that the major issue so far is a failure of the BEC IC in some ESCs. There was apparently a bad batch of components to blame. Then, the fans don't seem to be lasting long.

The MMM is already a 200A controller. The only thing that would make this great would be higher voltage, but that wouldn't be near cost-effective since it seems like a mojor replacement of components would be needed.

Aside from the switching BEC unit and lack of USB port on the MMM, what would be the advantage of switching brains boards from the two ESCs?

Hi Brian,
I start reading some of the threads and some shortcomings are getting clear and yes they can be fixed relatively by CC, hopefully soon.
I always hate fans and prefer to run without them, meaning design and built system accordingly.

Well, 200A I am not sure about this, just 12AWG wire and beefier pcb doesn't make it such a high current product, close but not quite. Just 6 extra FET's than MM and here we go 200A, I do not think so... Remember double decker MM was overkill by far and just proper heatsinking on standard MM, would get the same performance. I was hoping to see more improvements under the hood...

You right about high voltage, would be impractical.

The only reason for me to mix MMM brains with MM FET's, was to reduce foot print and gain 6S support with switching BEC (CC I am calling for MM-pro, with 5-6S native support and switching BEC. Do you need help in integrating that?). Now seeing all the problems with BEC, I think I need to focus on it first and then we will see...

[TexasSP]

I still don't understand why the CC bec circuitry was not integrated instead of the switching bec they decided to use. If it was a cost issue I would have gladly forked out an extra $20 to cover the costs. Other than the BEC issue, the controller was very smooth and ran cool the whole time. Of course in the 8-10 minutes I got to run it I never really got to give the fan a proper work out.

As far as the 200 amp rating, they seemed to back out of that one towards the end as no rating is available now. Patrick referenced something about different ways of attaining max ratings and not wanting to confuse the situation.

Once these little bugs are worked out, I still think it will offer the best bang for the buck out there.

[BrianG]

Yeah, getting rid of that fan, cutting away the top of the case, and maybe even replacing the heatsink is one of the first things I'm gonna do when I get a MMM. I too hate fans and think they are just a weak spot - and if a system NEEDS a fan to stay cool, then the components were not chosen appropriately for the speed/application it is being used in.

So, are you saying it's not a 200A ESC? What would you rate it at, taking into account temperature derating since these things are never at 25*C? What's the FET part number?

I'm kinda "meh" on the built-in switching BEC thing. Personally, this is how I think ESCs should come:

- ESCs rated up to 2s can use a linear BEC since the gains with a switching are minimal, if any.
- ESCs rated up to 5s should have the linear BEC, but the output to the Rx be auto-disabled after 2s voltage level forcing people to use external one. The linear BEC is fine for just powering the brains since load is really low.
- ESCs rated over 6s+ should be Opto.

[GriffinRU]

Originally Posted by BrianG

Yeah, getting rid of that fan, cutting away the top of the case, and maybe even replacing the heatsink is one of the first things I'm gonna do when I get a MMM. I too hate fans and think they are just a weak spot - and if a system NEEDS a fan to stay cool, then the components were not chosen appropriately for the speed/application it is being used in.

So, are you saying it's not a 200A ESC? What would you rate it at, taking into account temperature derating since these things are never at 25*C? What's the FET part number?

I'm kinda "meh" on the built-in switching BEC thing. Personally, this is how I think ESCs should come:

- ESCs rated up to 2s can use a linear BEC since the gains with a switching are minimal, if any.
- ESCs rated up to 5s should have the linear BEC, but the output to the Rx be auto-disabled after 2s voltage level forcing people to use external one. The linear BEC is fine for just powering the brains since load is really low.
- ESCs rated over 6s+ should be Opto.

I haven't removed heatsink, yet. But I am pretty sure it is the same as MM FET,
NTMFS4833N. As far current ratings I am ready at this moment, need to explore a little bit inside the ESC.

I will agree, sounds pretty simple to implement and safe to assume, plus stupid-proof.

By the way, BEC voltage barely used nowadays for brains power or FET drivers. This circuitries have their own power supplies with appropriate filtration, conditioning and current limitations. While BEC is mostly designed to be used with receiver and servos.

[sleebus.jones]

Originally Posted by GriffinRU

Well, 200A I am not sure about this, just 12AWG wire and beefier pcb doesn't make it such a high current product, close but not quite. Just 6 extra FET's than MM and here we go 200A, I do not think so...

Maybe so, but this thread pretty much removed any fears I might have:

http://www.rc-monster.com/forum/showthread.php?t=12116

The wire is 10AWG, btw.

[lutach]

This is getting good.

[jayjay283]

my mmm problem:
my MMM smoked, quick *poof*, after 12 minutes of running last Fri. I unplugged and sent it in, "wont pass quality control see you in June".. Just put a MM and 8xl back in for some lesser fun this weekend and my RX is smoked. I thought that smell was just left over death from the MMM smoking or my lcd TV getting ready to fart out..., it was my rx that smelled like that for a week. Must have happened when the MMM smoked because I havent touched it since and its smelled all week.... Possible ?

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