Xiao BLE Sense can power up with USB on PC not powerbank

I recently brought a Xiao BLE Sense. It is really nice board and I like it a lot! And with the simplest example - LED Blink uploaded to the board, I am trying to make Xiao running with a USB powerbank, so I can run it without connecting it to my PC. But Xiao doesn’t seem to power on at all. LED is not blinking, and powerbank will go back to sleep around 10 seconds later.

I am aware that Xiao has battery pins can support 3.7v Lipo battery, but I have already have some powerbanks on my hand, and I am trying to just leverage them.

I have also did the search and read this post already, but it seems like it doesn’t really have a problem for Xiao, but not Xiao BLE, which is based on nRF52, but not sure if this matters or not.

Hope someone has tried similar things and could help on this. It will be really appreciated!

Hi, I’ve just got into playing around with these things myself and think I’ve run into the same issue, apparently a lot of power banks have a power threshold to stay on and if a USB device is using less than that then it will stop supplying power and turn off to conserve battery. It makes sense since they are mainly used for topping up phones which will draw 1 or more amps while charging then drop considerably once they reach full charge at which point you probably don’t want the power bank to continually discharge. But sadly it makes them useless for low power devices like the Xiao BLE.

However you say that it is not turning on at all which makes me think you may also have the same issue as in the thread you posted where the line of code “while (!Serial)” will loop indefinitely and never start running the blink code, I got around that by replacing it with this code:

int serialAttempts = 10;
for (int attempt = 0; attempt < serialAttempts && !Serial; ++attempt)

That way if it is connected to computer you get the serial working, and if not then it will stop trying after half a second and run the rest of the program. Unfortunately my program still only runs for about 10 seconds before the power bank shuts off :frowning:.

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If possible with your power bank, what I do is hook up my phone (or led light or whatever) as well at the target board. The phone draws enough to keep the power bank from shutting down. Might or might not work for you.