I don’t actually have a problem, just wanted to share what I found while trying to keep the NanoWave 3 Power Bank awake while it powered a project that didn’t seem to draw enough power to merit staying on!
This seems to be a known issue with powerbanks in general, see remarks like “Power banks have an auto-off if they are not loaded with enough current. It takes about 50mA, you sometimes have to wire an LED across the supply, just for it to stay on (unfortunately).” on Quora.
I encountered this issue with my new NanoWave 3 Power Bank bought from Pimoroni, which I’d fully charged - it wouldn’t stay awake for a Waveshare Pico-powered clock, which presumably has a very low power consumption (it claims it consumes just 100nA of current, but that can’t be true, surely!?). The NanoWave would go to sleep almost immediately after the device was plugged in, which was no good for me…
There was no useful information on this in the ‘Hello’ leaflet, that was all the documentation that came with the device - and Nanowave Series Power Banks - 2-Power showed no sign of a manual, so the situation wasn’t promising. However, I found that if I held down the square button on the side of the device for about 5 seconds, its 4 tiny blue led lights would go out - and then count back in 1 by 1, from left to right. After this, the Nanowave stayed on - and has been powering my low-power device for the past half-hour or so without issue.
Hope this helps other users of the power bank!