Mamba Max Problems - RC-Monster Forums

**Mamba Max Problems -** 02.04.2007, 04:46 PM

I just finished a brushless conversion on my Sportwerks Turmoil. Since my 4S Lipos haven't gotten here yet, I've been running my MM on 3S 4Ah lipos feeding my Feigao 7XL motor. I was running the internal bec on the MM and was getting a really bad glitching problem. Well, I'm not really sure it was glitching. I could see the light on my Spektrum receiver go off and then back on. It's like I was loosing the radio signal. Since my external becs haven't arrived yet, I ran a receiver pack and the problem stopped.

Anyone had this happen before. Is my MM on its way out? Will the ESC keep working even if the internal bec craps out? Maybe I should buy another MM esc and send this one back to Castle.

Serum · 02.04.2007, 04:53 PM

the mmax bec is rated for 3S, so if you push it on 4S the BEC circuit is pushed over the limit. you solved the BEC problem. Remove the red wire from the esc to the receiver as well.

there is nothing wrong with your controller, it's completely normal it acted like it did.

So your mamba maxx isn't way out, but you are pushing it.

glassdoctor · 02.04.2007, 05:46 PM

What happens is that if the internal bec circuit is overloaded, it shuts off and back on again... many times per second if it has to. So this is just like a radio glitch, and the Spektrum makes it much worse because it's very sensitive to voltage dropouts. Spektrums actually take a second to "reboot" unlike a regular am/fm reciever.

So I bet it makes a hell of a glitch :)

glassdoctor · 02.04.2007, 05:47 PM

Let us know how you like the 7XL once you get the 4s on it....

Serum · 02.04.2007, 05:50 PM

Glass, you need to turn around your wings... I can smell them over here..

glassdoctor · 02.04.2007, 06:05 PM

Hee hee... I just did.. gotta go back and check em again.. later

02.04.2007, 07:31 PM

Thanks guys. At this point, I'm wondering how many of the glitches I've suffered have been caused by this.

I just need those becs to come in.

As for the 7XL on 4S, I can't even imagine (being new to the world of brushless buggies). Quite frankly, I'm starting to wonder whether the 3S with a 16T pinion might not be just right for the track. As it is now, it isn't super fast, but it gets to top speed in like 1.5 seconds. I'm still curious about how it's going to run on 4S. I'll have to see, because the smallest pinion that I can put on my setup is a 12T. Anything smaller and the can is hitting the rear support. I suppose a Feigo C model, or Neu is out of the question. Maybe I can ultimately get the new with the smooth can (although I read someplace that the screw hole locations are different on the smooth cans).

Thanks again.

glassdoctor · 02.05.2007, 01:37 AM

If you mean the rear of the motor is hitting the chassis brace? If so... then a slightly shorter can would help?... L or 1512.

:) going to 4s will really wake up the buggy.... you are in for a surprise. muahahaha

Last night I ran my 8ight in the house for a minute... (1512) and on carpet it was big wheelies, haa haa 1/8 buggies aren't supposed to do that. :) Good stuff

02.05.2007, 03:36 PM

I think the motor is going to hit the chassis brace regardless of which motor I go with. I'm just going to have to stick to pinions of 12T or greater. That's fine with me. If I understand correctly, going with the XL motors in the first place is all about more voltage and gearing anyway.

I was not disappointed with the performance at all, but that is a subject for another thread...

glassdoctor · 02.05.2007, 04:27 PM

Cool... larger pinions mesh better anyway.. Since I went to the @2000kv range motors I never run less than 12 either.