MM over voltage protection??

[spaz163]

Heres the situation, My friend fried his MM so he sent in $50 and they sent him what we assume to be a brand new one in a box with software/usb cable/manual and so on. The problem is that this new one won't run the 14 cells that he wants to so he can power his 9XL. It will run off of 12 but not 14... we even tried 14 old GP3300 and still no go.

The way that the controller is showing this problem is A: both red and green LEDs come on after arming and B: there is no power to the motor. Also, when both LEDs are on, the controller acts normal in the respect that when you pull the trigger the green LED flashes and when you push it back to brake the red LED flashes.

So my question to you guys is, has anyone else had this happen or is this ESC just some freak of nature? Also, if anyone has had this and came up with a way to remedy it... by all means, enlighten me!!! Thanks, Spaz!!

the mamba max is only rated for up to 12 nimh cells or between 2-3s lipo packs.
however, you can run a 4s lipo pack (14.8v) if you use a external BEC, like the dimension engineering sport BEC.

i don't know about 14 cells though, that is 16.8V, which is 2v higher than a 4s pack. but you should buy a external BEC anyway, and give it a try to see if the MM will work.
it sounds like you are getting a voltage over load warning from the esc.

[crazyjr]

Thats strange, I imagine its possible that they got a limit on voltage to limit how its used, but i doubt it. I have run mine at 5s Lipo and no overvolt anything but they are older

If you have an old software version available, try that. It does sound like over voltage protection, which Im quite sure mine dont have.
What voltage do your 14 cells read right off the charger? Try discharging the 14 cells a little bit at a time, see what voltage it stops working at. You might be able to run it on 14 not-quite-topped-off cells.

[spaz163]

Tried it with a reciever pack and it did the exact same thing, even went as far as trying a different reciever and unplugging the motor. All with the same results.

We did flash it back to 1.7 firmware version and that didn't help either.

14 EP4200 cells right off the charger come out a smidge over 20V, however I tried my really old 14 GP3300 cells and they had sat for about 10 hours after charging and it still "overvoltaged" with those.

Well it sounds like no one has had this problem yet so atleast you guys are now in the know if you get one back and both red and green LEDs come on... probably over voltage.

To remedy his problem he is going to run his MM in his Pede and he bought a Quark 125B to run in his E-Maxx, more suited to that situation anyways. Just gotta get a heatsink setup for it.

Thanks for the replies!!

[BrianG]

The newer versions of the MM use different FETs than the old MMs so it might be possible that the logic circuit disables the ESC at anything over X voltage. The old ones use the same exact FETs as the Quark 125, but the newer ones are different.

Here is a thread that discusses the differences between the old and new versions: http://www.rc-monster.com/forum/showthread.php?t=6349

[spaz163]

Thanks Brian, interesting read on the MM FETs. How many EEs are there in this forum? I am just a lowly Electronic Tech.

[BrianG]

I'm not sure. A few I think...

[nativepaul]

Could this be a sign that the MMM is on the way and there trying to build up a little more demand for it?

[suicideneil]

Originally Posted by nativepaul

Could this be a sign that the MMM is on the way and there trying to build up a little more demand for it?

Ah, another synical mind, just like me. I think you may well be right, even if the MMM is someway off; makes sure there are plenty of punters who know they have to get the new esc and cant rely on the old MM to do the job they want it to. Clever thinking on CCs part, but cruel too....

[mkrusedc]

Sorry got here late, but exact same thing happened to me:
http://monster.traxxas.com/showthread.php?t=385025
Funny how in the RadioConrolZone Joe Ford states there is no difference in the MMs.

[mkrusedc]

Sorry deleted double post.

[myndseye]

With my newest MM, using a 4S pack, it has this same problem. With mine, I just go into the quick throttle position setup mode when powering it on, and it works fine until I unplug it. Maybe you guys should try that.

[magudaman]

Awe man I hope this isn't a problem for me with my 5s A123 (18.5v) set I have in the mail right now on the MM with a 9XL. Guess we'll see this Friday when I get it all installed. I read else where that it is when it goes over 20v's.

[suicideneil]

Depends how old your MM is- if you bought it new in the last couple months you may have issues, but if you've had it a while or bought it second hand you should be okay with 5s A123 ( I say should, but you can never be certain).