Hello!
Hope i picked the right forum
I may need some checkin here to avoid damage to the components:
Until now i only controlled only one servo at one time and that directly via the arduino. But now im planing to controll 4 Servo Motors, which need to move simultaniously. Since a pin of the arduino should not get more the 40mA (correct?), im guessing i need to have power consuption via an extern battery and connect GND to this battery aswell, right?
For the pulses i need PWM-Pins (eg. 5,6,9,10), correct?
So i could power all this via an powerbank, which got two usb-ports - one for the ardunio and one for the servos. I may need some base load for it to work but anything else i need to think of? Is there a more elegant solution?
Those servos are power hungry and require 2.5 Amperes each. So, the external power supply needs to provide 4.8 to 6V at about 10 Amperes (about 50 watts).
Look at the "C" rating for maximum discharge. If the battery capacity C is 2.5 Ah (or 2500 mAh) and the C rating is 10C, then the pack can handle a 25 Ampere discharge rate (for short times).
Is it possible to damage the energy sources, if the motors are getting bigger loads? E.g. if I try to use two motors with the Powerbank (5A stall current Vs 3.4 A max single Output of Powerbank), will the motors just work "poorly" or can I damage the powerbank? What about simple AA batteries? I guess they won't be able to have an output as high as your advised battery packs, but again - is damage possible?
Since I don't think I'm gonna need all that power of the servos (and therefore will need less then the stall current) I hope to be able to use components I already have
Some of the batteries I use come with two C ratings, usually one double the other.
If it was 10C/20C we would think 25 amperes continuous and 50 burst mode maximum.
Of course at 25 Amperes the above battery would indeed last only ~6 minutes and I would be checking if it got more than a little too warm doing.
For the servos, you might get away with less than the calculated theoretical maximum current, if you didn't stall all four at once, for example or put them all to doing a heavy lift at the same time.
But the r/c batteries are generally good at supplying heavy current, scary good actually. Be careful.
That is not the worry. What gugu51 refuses to understand is that servos briefly draw the stall current every time they start moving, and in this case, the battery pack must be able to (briefly) handle 4x that, or at least 10 Amperes.
