HELP ! MMP + Spektrum RX = cutting out ?

So I went and bought a MMP to run my Ballistic 4.5 550 in my Hyper and it will cut out for a second when I hit the throttle or turn alot under throttle . You can see the light on the RX go out like its loosing power .

I have tried a glitch buster cap but that really didnt help , I have the latest software in it also .

Am I going too have to get a BEC also ? I was running a Novak Havok Pro before this and I NEVER had this problem ?

I also run 4 Mamba Monster systems WITH Spektrum RX's in different R/C's and they do not have this problem either !

[Arct1k]

I've heard of this on a few forums - sometimes the glitch buster was enough other times its taken a BEC...

[brushlessboy16]

Open the rx case and check for sand in the case, silica sand will short it out. I have had it happen multiple times

I have tried it with 3 different Spektrum RX's and all of them do it ?

[bdebde]

Are the motor and power wires routed well away from the rx?

Originally Posted by bdebde

Are the motor and power wires routed well away from the rx?

Yep , I have been doing this for a few years so I am not a newb .

This has really disapointed me since I have had great luck with Castles products in the past ..... Like I said I have 4 Mamba Monster systems and they work just fine with the Spektrum RX's . I think the issue is with the MMP's BEC or maybe something in the software ......

I have exact the same problem with my Tekin r1 esc and airtronics FHSS-2 receiver on 3s. My UBEC arrives tomorrow and hope it solves the problem.

I dont feel I should have too buy anything else to run this ESC , it has a built in BEC that should be able to handle any servo or RX its used with IMO .

I hope there is a fix for this soon , I dont want too have to spend MORE money when I could have bought a different ESC in the first place that I knew worked instead .

[BrianG]

If you are running 2s the voltage could be dipping under acceleration. BECs need around 1-1.5v higher than the output to run right. So, if your BEC is set to 6v, anything much lower than 7v at the battery could cause the BEC to dip below what the rx needs. You could try setting the BEC to 5 or 5.5v and see if that helps. I would keep the glitch buster cap in there too; it may not noticeably help, but it does smoothen the voltage and reduce any noise.

Hmm , tried lowering the voltage on the BEC and it seemed too help a little but it still cuts out and hesitates pretty badly . I guess I will try an external BEC next . Either that or sell it and take a loss to buy a different ESC .....

[BrianG]

Are you using 2s? I'll assume you are. No matter what BEC you use, you still need a battery with 1v-1.5v higher than the BEC rating. 2s being at 7.4v doesn't leave much leeway for voltage drop. The only real solutions for 2s usage are:

- Use a better battery that doesn't dip as much under load (higher C rate)
- Use 3s. Of course, that would require gearing and maybe even a motor change to keep speed/rpm in range.
- Lower the BEC to 4.8v or 5v to allow more leeway. Even then, if your battery voltage is sagging a lot, this won't help much.

For 2s applications where battery sag is going to happen no matter what you do, I would actually suggest using a linear LDO (low voltage-dropout) regulator. You may be able to find one capable of 3A+ and less than 1v dropout (BGMicro.com used to have some), but would be easier to use a lower current LDO regulator (like 100mA) and add a pass transistor to get 3A+.

BrianG , why would Castle put this thing out if it wont run on 2s properly ? Its a 1/10 controller and MOST 1/10 scale cars run 2s ? I am using 30c batteries so they should be able too supply enough power .

I even tried an 8000mAh 25c battery and it still does it ? Never heard of this with the Mamba Max so whats different now ?

[BrianG]

I really can't answer the purpose of the design, but what I said does stand. It's simple electronics and math, and they don't lie.

I know from experience that Spektrum receivers do tend to be finnicky with regards to power. Usually, adding a ~10,000uF capacitor (glitch busters) eliminates the problem.

Another potential issue could be the servo. If it is binding, very high torque, etc (basically pulls a lot of current), it could be causing the BEC itself to drop out, which causes the spektrum rx to hesitate.

The Mamba Max uses a linear regulator, which is good up to 2s (sometimes 3s if the servo load is small). Linear regulators are generally pretty darn tough and can handle all kinds of abuse gracefully. But above 2s, the internal BEC should be disabled and an external switching BEC should be used to keep it from thermalling. The MMPro uses a switching BEC. From experience, this BEC can supply a little over 2A before it drops-out.

I installed an UBEC today and the problem solved...

Well , I also went too the LHS and picked up a CC 10a BEC , put it in and it seems to have cured my problem ? So why cant the BEC in the Mamba Max Pro do the job ? Is there some kind of fault with them ? I am using a high torque servo (JR 9100T) but I use that servo in all my 1/8th scales and the MMP ESC is the only one that is giving me trouble .