OK, a good suggestion, so I tried it and all is well. Here’s what I did using my Anker 13,000 mah power bank:
First things first: be sure to turn ON the power bank! I had to for my power bank. I tried charging the MPW first time with the MPW off, and plugged the (2.1A out of) power bank in – no blue light on MPW indicating charging until the ON button of power bank was pressed. I started with a 95% charge on MPW, in a short time, it was at 100%. Of course, to see the UI, I had to turn on the MPW. Then, I removed it from the power bank and let battery run down to 95% again, then again plugged in the power bank. It got charged to 100% again, but took a little longer because MPW was now on and running.
So, the power bank charged the MPW when it was in both OFF and ON conditions, and charged faster when MPW was off.
Edit: Corrected above that said, "95% again, but took a little longer . . . " to be 100%. Oops.
