FD 1/8 Buggy Stutters
 

Hey guys. I picked up a used FD 1/8 Scale buggy. Torn it down and rebuilt it so I know all inerts of the buggy are ok.
Got it all hooked up programmed the 9920 and disabled the BEC, Running a 5 hump 1400mah and a JR AM radio.
Here is the issue: I can ease into the throttle and it goes ok - sometimes even at 1/8th throttle it will stutter (like the motor turns off and then back on). When I attempt full throttle it hesitates like crazy trying to find its self then it will grab but will soon release (stutter or shut off/on the motor) I almost makes a barking sound.
Any ideas?

Thanks

What motor? Maybe try a UBEC .

The motor is the Nemesis XL. I tried the UBEC on the 9920 but same problem

Hmm, i am not positive but it can either be a problem with the motor or esc. Would you possibly have another esc or motor to try out ?

Can I take my MM ESC off my ZX-5 and use that one? If not a wise decision, then no I dont

Yes you can, that should be able to tell you and us what the culprit is..

Thanks - but can the MM ESC handle 14.8 Lipo battery ok?

Yes. It handles 12 cells, which is 14.4v nominal, so there is no reason why it won't handle 0.4v more of a 14.8v 4s lipo pack. Even right off the charger, 12 NiMH cells is 16.8v (~1.4v each), which is exactly what 4s lipo is. And then, the ESC has a built-in LVC setting for 4s too.

Yea, just dont forget 4s lipo fresh off the charger are (~4.2v each) which is 16.8 so it is equal to 12 cells. Some people have even tried 5S with sucess.

Cool - thanks for the help!!

Anytime! - report back when and if you find out what is causing the problem.

Make sure to pull the red wire out of the rx plug.

Ok, got it all hooked and all out of the buggy. All seems to be ok at the moment. I tested forward reverse. Motor gets warm but everything else is cool. It only studdered twice but it is nothing like it was b4. Gotta love the MM esc! Only bad thing I can say about them is - what the hell kind of solder do they use to solder the wires to the board? It took forever to get it to melt!

Ok, so the esc was bad... Its not the solder they used, is the way they soldered it, i bet they must use a VERY hot machine or gun to sauter them!

Sounds like you need a larger tip for your iron. Big gauge wiring requires a lot of energy to get it heated up quickly. The only way this happens is by having a large enough tip that can sink its stored energy to what it touches. Bigger (thicker) tip, more stored energy.

The circuit board where the wires enter looks like at least a dual layer board. And, the traces are kinda big and act as a heatsink when you are trying to solder. You have to be careful not to put heat on the solder joint for too long or the heat will travel along the traces and heat up whatever is nearby possibly damaging it. It's better to use a hotter iron for a few seconds than to hold a cooler iron on there longer.

Negatory - I have a big hot tip on it and have no problems soldering most things. I have never ran across solder such as this is all I am saying - it was a bio*tch lol

Ok its doing the same thing with the MM ESC - I did find a back connector on one of the motor wires so I am going to redo the connectors and try again.

Oh Happy New Year!!

Happy new year! Maybe one of the motor wires is damaged..

Is there a way to replace the motor wires oneself?

Make sure the motor screws are not too long and shorting to the motor windings.

I haven't taken apart the Mamba Max motors, but in the manual it says you can cut as much as you want (within reason). They must attach wires to the coil ends within the motor. I, and others, have tried taking off the end bell and couldn't undo one or more screws.

I have the FD Nemesis motor (XL) Any luck replacing the wires on these or just send them back?

Well, you can't cut much wire off those. When they made the motor, they wound the coils, and brought the ends out to attach connectors to. They had to scrape the insulating varnish off the individual conductors so the solder would stick. If you cut the wires, you'll have to do the same thing. It's not fun. If anything, you could replace the connector. Just heat up the solder joint and slide it off.

Ok, update. I re-soldered the connector onto the wire after cleaning it and the wire end. Got it all hooked up and it runs perfect! I will try the 9920 again as I suspect the motor wire was the culprit on it as well.

Goes to show how important good connections are!

Great!

A loose connection can cause all kinds of headaches, not to mention less-than-optimum performance...