PDA

View Full Version : [Question(s)] Battery recommendation for mx-64t dynamixels



adityassripada
07-03-2014, 10:58 AM
We are using a set of 6 MX64-T Dynamixels connected in a daisy chain for a biped.Which batteries will be ideal to power up these Dynamixels ? Each of the Dynamixel draws 4.1A at 12V.

Can we connect the batteries directly to the Open CM 9.04's battery slots directly to power-up the motors ?

Controller : Open CM-904B

Motors : MX-64T Dynamixels

tician
07-03-2014, 07:21 PM
The MX-series servos work best with 12V (3S LiPo). The battery should be labeled with a 'C' rating that, combined with the capacity, will tell you how much current the battery can safely provide to the servos (2300mAh capacity * 15C_continuous_rating = 34.5A continuous). The 'recommended' torque is ~1/5 of the stall torque and the MX-64T should only require 4.1A when stalled, so the sustained current of all the servos should be a bit less than 6*4.1A but failing to meet the surge current requirements can cause serious issues (servos can behave erratically and sometimes reset their IDs).

The pair of series wired, two-pin battery connectors on the OpenCM-904 are only rated ~2A, and intended primarily for XL-320 servos with the pair of 1S LiPo batteries of the Darwin-Mini (AX-12 are usable when powered through the CM-904 with 3S LiPo, but it is still best to add a powered hub). You will need to power the MX-64T servos through something like the trossen AX/MX powered hub (http://www.trossenrobotics.com/6-port-ax-mx-power-hub) or custom cables to connect the battery to the power and ground pins of the servos.