user84848: I have setup two ESP32-CAMs, sharing the signal from a PIR sensor via an optocoupler.
Plus I have a 12V LED ring on a 5V to 12V booster, turned on/off by a relay.
The ESP32s go to deep sleep, wake up on the signal from the PIR sensor, turn on the 12V IR LED ring, take some photos and go back to deep sleep.
When they are on three separate power circuits, they seem to work well.
Is it safe to connect all these to the same USB output from an USB power bank?
Or can it be done safely at all?
(Could be similar to this question but I'm not sure.)
I am new at this and I don't have any intuition about whether that would create odd voltages and currents that might damage the components on the long-term, as they keep turning on/off and draw varying amount of power.
Instead of three USB connections like this:
(trying to illustrate only the power circuits)

I would like to power them on one USB connection:


user4143: There is no difference between your circuits. Internally to the powerbank all three outlets are typically wired together just like in your second schematic. One outlet or three outlets it's all the same.

84848: <p>I have setup two ESP32-CAMs, sharing the signal from a PIR sensor via an optocoupler.</p>
<p>Plus I have a 12V LED ring on a 5V to 12V booster, turned on/off by a relay.</p>
<p>The ESP32s go to deep sleep, wake up on the signal from the PIR sensor, turn on the 12V IR LED ring, take some photos and go back to deep sleep.</p>
<p>When they are on three separate power circuits, they seem to work well.</p>
<p>Is it safe to connect all these to the same USB output from an USB power bank?</p>
<p>Or can it be done safely at all?</p>
<p>(Could be similar to <a href="https://arduino.stackexchange.com/questions/28930/is-it-safe-to-use-the-same-power-source-for-arduino-and-its-motor-shield">this question</a> but I'm not sure.)</p>
<p>I am new at this and I don't have any intuition about whether that would create odd voltages and currents that might damage the components on the long-term, as they keep turning on/off and draw varying amount of power.</p>
<p>Instead of three USB connections like this:</p>
<p>(trying to illustrate only the power circuits)</p>
<p><a href="https://i.stack.imgur.com/Ezo0c.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Ezo0c.png" alt="three usbs" /></a></p>
<p>I would like to power them on one USB connection:</p>
<p><a href="https://i.stack.imgur.com/eBkM0.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/eBkM0.png" alt="one usb" /></a></p>
 4143: <p>There is no difference between your circuits. Internally to the powerbank all three outlets are typically wired together just like in your second schematic. One outlet or three outlets it's all the same.</p>
