Voltage and Current Required for 4 25kg servos

Other Hardware Motors, Mechanics, Power and CNC
1

My project requires the usage of 4 25kg servos, that could potentially need to run at the same time at different points in time. I looked at the internet which says that I would require 3-4 Amps per motor - this means 16 amps - I got a step down convertor and a buck convertor to supply 6v 20A - would i require all this current (kinda dangerous amount and power supply kinda sketchy)

Also, I have a PCA9685 (which is going to be directly connected to the power supply) which I plan to use to control the servos - i know that the voltage rating for it but I couldn't find any sort of current rating anywhere - is it safe for me to plug the servos in directly or do i need to wire things on my own

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That doesn't sound like a good idea. Plus provide some part numbers, and a proposed schematic.

I assume you are talking about RC servos.

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Step down and buck is same thing... So what you got?

VCC has to be connected to max 3.3/5V depending on your arduino.
Only V+ / V- can be connected to 6V.
PCA9685 does't give motor current rating, because motor power doesn't run through the chip.
For power supplies, more amps means just more capacity. It doesn't anyhow over power your circuit even if you have 100A PSU.

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FYI - Power (energy) is calculated as Voltage x Current so a higher voltage servo would require less current.

And like kmin says, for control you just need a (low power) signal.

Servos have a built-in motor-driver circuit so you just need the signal and an adequate power supply.

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my bad my head was kinda spinning - i just have one step down/buck converter which is rated for a max output of 20A (voltage is variable however plan to keep it at 6v)

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So if I connect the power supply directly to the PCA9685, the power itself will bypass the chip right? - Assuming it is wired in parallel it should be fine in theory to push a max of about 15-16 A for the whole thing (3-4A for each motor) - Servos do have their own control circuit so do I have to split the 3 connector wires for the motor and connect only the PWM wire to the control board?

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Are using a PCA9685 module? If so which one?

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Yeah about that - I am not using the genuine ones from Adafruit - I got 2 knockoff ones from amazon but its not a problem if I have to use the original thing - but apparently the only difference between the two is the lack of transistor - they both contain the PCA9685 chipset so if I am mindful of the polarity it shouldn't be a problem right?

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As long as you don't connect 6V to VCC.

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Ok, I guess it is one like this DollaTek PCA9685 16 Channel 12-bit PWM Servo motor Driver I2C Module Robot: Amazon.co.uk: Business, Industry & Science

As you have already seen, they copied the silkscreen which says it is polarity protected but not the component that would provide the protection!

The original board is recommended to not more than an 8A. The copy is surely rated less than the original, so I would be wary of putting even 8A through it.

I would wire the servo's power terminals directly to the PSU, just take the signal from the PCA9685 board. Connect GND to PSU.

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