Can running too many servos (4) on a speed control and 3s battery, damage the speed c - RC Groups
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Aug 23, 2009, 12:37 PM
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Joel K. Scholz's Avatar

Can running too many servos (4) on a speed control and 3s battery, damage the speed c

I am running into something I have never encountered before. I have added a moveable CG system to my Hawkeye utilizing a Dualsky 40 amp speed control. This control has a 3 amp BEC rated for 4 micro servos on a 3s lipoly. I have 3 micro servos and a high torgue servo on the system. When hooked up, the motor refuses to turn and makes a screeching sound. I hook up another speed control ESkY 25 amp control with dual BEC and motor runs normally. I disconnect all servos and use original 40 amp on motor alone. Motor screeches and will not run. I put the same speed control on a different motor and it operates normally? I am afraid to hook up a new 40 amp controller to the setup as I am afraid too many servos could damage the controller. any ideas as to the problem?
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Aug 23, 2009, 12:55 PM
Xpress..'s Avatar
High torque servos can draw more current, so theoretically you could be over running the ESCs BESC, causing it to shut down or refuse to work properly.

Use a seperate BEC and you won't have problems
Aug 23, 2009, 12:56 PM
Registered User
An ESC will have one or two thermally protected regulator for your servos. If you draw too much, it shuts down until it cools a bit, then it turns back on.

Most likely you haven't broken your ESC with the load, but something else is going on.
Aug 23, 2009, 12:57 PM
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pilotpete2's Avatar
I would not use the built in 3A BEC with that high torque servo for the CG in the mix with three micro servos, that servo for the CG will pull some real current while shifting things, I would think
The issue with the motor screeching and not turning sounds like either a timing issue, or one motor wire connection is bad.
Good luck,
Aug 23, 2009, 01:00 PM
Xpress..'s Avatar
Also, potentially you could fry the servo if the loads on the CG mechanism are too great. Hitec has some new digital servos that draw significantly less current than previous models but put out MORE torque
Aug 23, 2009, 02:32 PM
Former Futaba employee
Sounds like a motor timing problem?
Aug 23, 2009, 02:47 PM
Registered User
Motor "screeching" is discussed in following thread:

See post #1090
Aug 23, 2009, 09:29 PM
Speed cost money.
highflier's Avatar
Yes to many servos can damage the ESC. If the ESC has a linear bec the rating or 3 amps is likely to not be with a 11.1 volt battery. More like 2 amps. If you have a switching bec built in then it most likely will handle 3 amps with an voltage you use.

Aug 23, 2009, 09:45 PM
homo ludens modellisticus
Ron van Sommeren's Avatar
About BECs, #servos and battery voltage:

About de-rating controllers and motors, starting at 'for everyone else':

Vriendelijke groeten Ron

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