I'm powering 12 servos using a 7.4V 8000mAh battery. Each servo's input voltage is 6.0V. I'm controlling them with the same Arduino PWM pin. One randomly burned out while it was holding an angle, and I have no idea why, because it was working fine lots of times. I did notice a humming noise that would come and go from all of the servos. I'm guessing that either that was a short, or a spike in Voltage.
Does anyone have any tips for avoiding shorts or maybe regulating voltage so I can prevent this in the future when powering and controlling lots of servos.
Chris33:
I'm powering 12 servos using a 7.4V 8000mAh battery. Each servo's input voltage is 6.0V.
Are you powering the servos directly from the battery without a regulator?
BTW, Your battery will likely be 8.4V when freshly charged. This is high enough to burn out many servos.
What program are you using with the servos. The Arduino's default 0 degrees and 180 degrees are beyond the limits of many servos. You might need to change your code and add a regulator.
Edit: Take a look at this thread for some additional information about voltage regulators.
You do not need to use an Arduino PWM pin to control a servo. Any pin will do.
The signal that goes to a servo is commonly called PWM but it is not the same as the PWM that an Arduino produces with the analogWrite() function - which does require the PWM pins. analogWrite() is used to control the power going to a DC motor or an LED. The servo signal instructs the servo what angle to move to.
The double use of the acronym can be very confusing.
It is important that the servo grounds are connected to the arduino grounds like in the attached pix. If a servo is driven against its internal hard stop, it may be damaged or burned out at high voltages.
Also, a servo buzzing or getting hot may be an indication it may be straining against the internal hard stop.
Too much physical resistance to the free movement of a servo will mean it pulls a continuous high
current and overheats. Hitting the end-stop is one example of this.
With such a powerful battery I strongly recommend having a physical fuse in the system to protect
the wiring - after 160 amps will rapidly make all the wiring incandense and catch fire should there
be a physical short circuit. Wear eye protection whenever dealing with high current sources, big fat
sparks can shower molten metal...
