Wild Thumper Responds Briefly to RC, then stops

[apologies, I was sure I posted this but cannot find any evidence of this post on the website. Please ignore if it is a dup]

I have a Wild Thumper on a standard Dagu chassis using the sample firmware.  Flysky 3-channel RC transmitter, hooked up to D0, D1.

7.2V nicad charged up and attached.  Demonstrated that the motors are driven using the diagnostic Arduino Wild Thumper code.

With the RC, I can get the motors to move in the right direction (power, steering) for maybe a 1/2 second then it stops dead.

This suggests something about the current sensing.

Any other possibility?

If it is the current sensing, the 'calibration' instructions really make no sense to me. They refer to an external automotive light bulb then a few sentences later the motors that are attached.  Can someone convert those instructions into English? :-)

I would assume my 'vanilla' configuration would have the samples set properly for the Dagu chassis:

#define Leftmaxamps        800     // set overload current for left motor  // 800

#define Rightmaxamps       800     // set overload current for right motor 

#define overloadtime       100     // time in mS before motor is re-enabled after overload occurs

photos are

photos are here: http://imgur.com/a/rdTsA

The battery is an 1800mAH NiCAD.  There’s no power switch, it’s directly wired in when the battery is connected.

When the Dagu chassis is in the air, it runs continously as expected. However, on the ground, when the motors encounter any friction, it stops nearly immediately.

I’ve tried tweaking VR1 and VR2, but I’m not getting the reading as expected using the Diagnostic PDE so I don’t want to adjust it too much blind.  


Any decent RC car race pack

Any decent RC car race pack should deliver 30A, the question being “for how long” rather than “whether”? I am unfamiliar with current brand quality, especially with those linked. Long ago I used to buy mine from dedicated RC racing sites rather than hobby stores or general sites.

My view on the problem is consistent with earlier comments in that I am wholly unimpressed with the wire guage I see in the images, and suspect the NiCd may be a little tired compared with a pack new and capacity tuned.

Fix the wire guage. Check every connection for solder quality (and every one of them adds resistance anyway). Yes, buy bigger brighter better batteries. Really good ones may cost actual money so start with only one while checking solutions.NiCd works but NiMh is better. In any case (including LiPo) for the best result you need charging matched to the battery type.

Still, I am curious why it would stop after “half a second” given nothing is melting (Are the wires very hot? The motors at all? Battery?  Controller?). What is the battery state after half a second when an alternative high-amperage load is applied? Is the battery pack new? Do you have a proper RC car pack charger, one that provides cell condition informaton?