Comments

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  Colin December 1, 2011 at 3:22pm

  Turnigy sentry ESCs might be worth a look in, they have switching BECs built in, so can handle something like double the current on the 5v line whilst also being more efficient
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  Anish December 1, 2011 at 3:06pm

  Castle seems to be better, I do have castle Mamba xl for my "baja ardurover" I haven't tested it yet ....but my test bench gave decent results
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  David Long December 1, 2011 at 2:41pm

  I bought a Castle BEC a few months ago and I've been staring at it :) wondering: Is the BEC necessary because the ESC is designed poorly?  Why doesn't someone make an ESC that isolates the motor pulse circuit from the BEC?
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  Anish December 1, 2011 at 10:15am

  @David i tend to use BEC's i do admit having doing some analysis and it doesnt look that great. I generally use hobbywing pentium or similiar once for ESC
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  David Long December 1, 2011 at 9:37am

  I really am of a mixed on this.  On the one hand, the amount of current that the ESC must supply to run the servos, APM, Rx, and Xbee is trivial compared to the motor's draw.  (This points to quality, not quantity.)  But the fact that longer servo leads causes the APM to send erratic signals makes it seem like power threshholds might be involved.  I guess what I need to do is throw an oscillascope on the leads coming out of the good and bad ESC and find out what's happening. 
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  David Long December 1, 2011 at 9:30am

  Warren... Yep, the Xbee is on there too.
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  Warren Eather November 30, 2011 at 11:33pm

  David, that is interesting! I,ll have try the shortening of aileron cables. Do you have a xbee connected? Maybe the extra cables are acting as an antenna inducing a bit of voltage ripple on the apm.
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  David Long November 30, 2011 at 9:51pm

  Warren, I agree with you on the quality of the current being the big factor.  However, capacity comes to mind... when I removed the aileron servos (which together have leads about a meter long) and attached a single lightweight servo with no extensions, the problem vanished.  When I added two or three servo extensions to this "good" servo, the problem reappeared.  Somehow, the added resistance of the long servo leads puts an unworkable load on the APM.  (I fly RC pattern planes and I have noticed that larger ESCs increase servo performance and resolution.)
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  Warren Eather November 30, 2011 at 8:58pm

  Hi David, I think your right about a funky ESC being the cause of your issue, but I believe that it's due to the quality of the BEC's regulated 5 volts than the current rating of the ESC. My ESC was suppling a noisy 4.5 volts with similar results that you experienced. I.E. Pulsing servos and intermittent APM rebooting.
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  David Long November 30, 2011 at 8:18pm

  I realized something that I should have picked up sooner:  When you install an APM in a model plane that calls for, say, a 30 amp ESC, you may need to increase the size of the ESC.  I was recently getting some strange bugs (servos moving erratically in synch with the blinking GPS LED and the APM resetting spontaneously).  Clue: the problems decreased when I shortened the wing servo leads.  I slept on it and decided that the only thing the GPS, board logic, and all the servos had in common was power.  I put a 60 amp ESC in and, shazaam, no more problems.