Need advice for powering a robot

My goal is to build a 4-legged robot that I can hook to a wireless ps4 controller and walk it around. My problem lies in powering the robot without the use of my laptop/computer.

My Arduino is plugged into a PCA9685 which allows me to hook up a max of 16 servos. Each leg of the robot uses 2 servos for a total of 8 servos (TowerPro SG90's). The PCA9685 requires power so it can power the servos and I can't seem to figure out a good way of doing this. I am very new to the electrical engineering world so giving components the correct power is still quite confusing.

What suggestions do you have for powering this robot?


It may be useful to start by estimating the working voltage and max current you need to supply to your robot's servo motors via the PCA9685.

For example, each SG90 is rated for 4.8-6.0v and is estimated to consume ~270mA (up to ~730mA when stalled). With 8 servos active concurrently, you may draw >2A (no motors stalled). Powering this from your PC could be problematic (USB 2.0 is typically rated for 0.5A).

You might want to consider a standalone 6v NiMH battery rated for the expected current draw you estimate.

For example:

Have fun with your robot build!

NiMH is a good idea. If you do not happen to have loads of LiPos or 18650 laying around, that's a save way to go.

Note that unless you are really good at design, you will want the Arduino (A Nano - obviously not a UNO) to be powered by a separate 5 V regulated supply. For basic work, possibly a 5 V phone "power bank".

An easy solution would probably be to get one of these: 5pcs 5V Boost Step Up Power Module Lithium LiPo Battery Charging Protection Board LED Display USB For DIY Charger 134N3P Program|power module|protection boardstep up - AliExpress
and connect an 18650 cell or a flat LiPo to it. Then your Arduino could safely pull power from the USB port.

if you decide to go for an 18650 cell (you can basically get them for free if you know where to look), one of these would come in handy: Black 5pcs/set 18650 Batteries 3.7V Plastic Battery Case Holder Storage Box|Battery Storage Boxes| - AliExpress
as I wouldn't recommend soldering to the cell directly unless you know what you're doing.