# How do I calculate how much power a servo consumes for specific degrees of turns?

I have an FS5103B servo with a stall current of 780mA at 4.8V. So say I am calculating power for the stall current as P=UI^2, I get 2.92W. What does that mean, like is it for a one-degree turn or does it depend on how fast it did the turn? And also how do I go about calculating how much power it consumes for a specific degree of turn.

Thank you very much in advance.

• "Stall current" = "isn't moving." There is no rotation when stalled. Power will depend on the load, not the number of degrees of rotation. – JRE May 4 at 21:48
• Oh, I thought stall current means the current consumed by the servo when it is applying maximum torque, in my case 3kg, is that incorrect? – noname197 May 4 at 21:49
• Yes. The servo applies maximum torque when it is stalled - it just doesn't move. – JRE May 4 at 21:50
• You can't calculate power for a turn of 1 degree. Power is instantaneous, but a turn takes time. You can measure the peak power during a turn, or the average power during a turn, but you can't say "2 watts for one degree." What you have to do is to measure energy. That's power*time. – JRE May 4 at 22:00
• But servo power is not linear and continuous. A certain amount of current is required to start it moving, which also depends on the attached mass. Then current declines as it accelerates. And stopping can actually generate current (which is usually dumped or ignored.) So less energy for one movement of 5 degrees, as opposed to 5 movements of 1 degree. This sounds like a candidate for experimentation. – rdtsc May 4 at 22:30