[suicideneil]

Fools.

MMMs have been failiing on 4s and 6s, so its not a question of voltage at all, in the slightest, nada.

When the esc pops a few fets or goes up in flames, thats due to excessive current draw, usually through a bad or weaker fet; hence the reason why any esc can go pop if you push it to hard or have an amp hungry motor.

BEC failures (the majority of issues reported) are due to something else- most likely poor circuit layout, or bad components, as has been theorized elsewhere.

The MMM is rated for 6s lipo, only limited really by a component that is rated for about 25.8v, so running 6s lipo (22.2v, or 25.2v peaked) wont kill the esc.