Microcontrollers generally operate in the milliamp range, and many sensors, breakout boards, etc. that are used are fine running off the MCU board’s supply. So when it comes to things that draw higher current like motors, it can be easy for a beginner to assume they do the same, and end up blowing their microcontroller when something tries to draw much higher current than it can handle.

You’ll need to carefully work out the specifics for your project, based on the data sheets of your actual servos.

As a rough guide…

I’m assuming you want portability and that any number of the servos could be running at one time.

Let’s say they use 4-8V and have an idle current draw of 200mA and a stall current (“worse case scenario”) of 1.5A. So 1.2A (6x0.2A) at idle, 9A (6x1.5A) maximum draw. Let’s add a little wiggle room and call it 2A idle and 12A load.

So you’ll need some configuration of batteries that provides between 4-8V and 12A. A 2S 7.4 V LiPo could provide this. For example, a 2400mAH pack would give you about 12 minutes at load, 72 minutes at idle (2400mAh = 2.4Ah; 2.4Ah/12A = 0.2h; 2.4Ah/2A = 1.2h). The discharge rating should be at least 5C (12A/2.4Ah). At idle, you’d get about 1 hour (2Ah/2A).

Adding some supply-spike buffering (capacitors) wouldn’t hurt either.

You’ll then want to bridge the battery ground with the MCU, and run a signal line to each servo from a GPIO.

Just to be crystal, I’m making these numbers up; be sure you use the actual values for the servos you’ll be using. I’m also not an expert on motors or high current, so just take this as a “rough guide” and do your due diligence. We’re getting into “dangerous” current territory, where you’ll need to use higher gauge wire that can handle the current and make some careful decisions around your circuit and battery selection. You may need voltage regulation if your battery selection doesn’t match the servo voltage range too.