MMM Explodes into FLAMES! - RC-Monster Forums

BrianG · 07.12.2009, 03:01 PM

TBH: I don't like running ESCs to their max voltage value. There just isn't enough headroom for me. The TVS on the MMM is rated for 26v IIRC, and at 6s, a system can generate enough EMF when braking to stress it and blow it. And when the TVS blows (which is probably not noticeable to the user), all that EMF energy is no longer being clamped and the FETs, caps, and batteries have to cope with it instead. I like to run 1s below the rating, so, for the MMM, that's 5s. No problems so far on either of my two MMMs. Even on a Quark (which is rated for 6s too), I run 5s max in any of those systems, and those have been solid.

The only ESC I run at over it's advertised spec is the MM (on 4s), but that is because I feel it is underrated. 25v caps and 30v FETs. The only limiting factor IMO is the built-in linear BEC, which is easily remedied with an external switching BEC.

Should the MMM be totally reliable up to its rated spec? Sure, but as said, everything has to be "ideal" when running that close to the edge. Any one thing out of whack can cause "issues" as we've seen. Why is it that some people (maybe the majority) can run fine all day long on 6s? I dunno, maybe they are lucky, happen to have cream of the crop components, or simply not as hard their stuff.

e-mike · 07.12.2009, 03:49 PM

¸¸¸¸ I don't like running ESCs to their max voltage value. There just isn't enough headroom for me. The TVS on the MMM is rated for 26v IIRC, and at 6s, a system can generate enough EMF when braking to stress it and blow it<<<<<<.

castle should put a higher devise to prevent some failure????

BrianG · 07.12.2009, 10:53 PM

Quote:

Originally Posted by e-mike

...castle should put a higher devise to prevent some failure????

Maybe, but that would involve a total redesign. Not sure if they are willing or see the need for it. As long as people understand the limitations, 6s should be ok.

Besides, the reasons I stated are just MY opinions/theory. It doesn't mean they are correct. But, the evidence sure supports it. How many 4s or 5s setups have you heard of flaming up vs 6s setups? I'm sure there are some, but those are probably just the normal statistical failures.