Is it safe to Power m5paper and m5ink with fast charge 20W power banks?

  • Hi

    I have m5paper and m5 core ink. But I need long battery backup. Even with m5.shutdown every 10 min and waking up for 30 sec to fetch remote data m5paper lasts for less than 2 days.

    So I was thinking of powering these with something like 27000mAh battery pack used for mobile phones. They are supposed to be operating at 20W. I wanted to know if it safe to power M5paper and m5 core ink with these battery packs?

    I am thinking of this one:

    Sorry I don’t understand much on the electronics side. Please guide.