I'm trying to figure out how to operate six MG996R servos using a 7.4V input voltage (up to 8.2V max), which I'm getting from a pair of 18650 batteries connected in series. However, I'm struggling to find a clear solution that doesn't involve using a step-down buck converter. It appears that servo drivers, such as the PCA9685, require a pre-regulated input voltage, and every step-down buck converter I've come across doesn't seem to support the output current necessary for all six servos. I would greatly appreciate any advice on this matter.
The start/stall current of the MG996R is 2.5 Amperes, and each servo briefly draws that current every time it starts moving.
So, plan on a servo power supply of 4.8 to 6 V, capable of providing at least 10 Amperes (more if all of the servos will be moving at once). There is no chance at all that 2x18650 will suffice.
Thank you for the prompt response. Would a 2S2P configuration suffice? It looks like a 2S2P battery pack would provide roughly 6.90Ah. Considering the maximum current draw of 15A, this should last me about 25 minutes, which is plenty for a brief project demo at the school.
Ideally you will use a voltage regulator that can handle more than 15A peak, and individual cells rated for peak discharge current higher than 7.5A (parallel connection).