PowerBank that supports indefinite trickle charging?

My wife and I have a son with a heart defect. When he was born, he was attached to multiple wires to monitor his breathing, his oxygen, and to supply supplemental oxygen as well. Over the course of the past year, we’ve weaned him off of supplemental oxygen almost entirely. We also no longer need a medical-grade o2 monitor and his Owlet Smart Sock comes into the picture. Then I discovered that the little base-station, a puck about 1/2" high and 2" across, could run off of a battery instead of needing a 110v outlet.

Many moons ago, a company named “Lime Fuel” started selling the first consumer-grade Li Ion rechargeable batteries for cell phones. Available via Crowdfunding at first, if I remember right. It can power his Owlet sock for about 5-6 days before needing a charge. We had 2 of them which allowed us to charge one while the other was in use. This meant we could be FREEEEEEE and go places with our son.

And the other day one of the batteries died. No longer takes a charge. No problem, my favorite company, Anker, to the rescue. See, we’ve got Anker wall-warts, desk chargers, 10 port USB hubs, 8 port USB hubs, laptop docks, batteries, SoundCore speakers… the works.

So we bought a PowerCore 325 w/ 20k mAh… This sucker will run the sock for a good 10 days, I bet… except it doesn’t.

The reason the sock’s base lasts so long is because it draws so little power (duh). A little bit of master sleuthery (that’s a real word, shush) and I find out it’s because the PowerCore 325 thinks the device it’s charging is full and doesn’t need anything more. Oh, but I found out that it supports trickle charging with a simple 3-second push of the button. And POOF, I get a little green LED telling me that it is indeed trickle-charging now!

Except when I got up about 3 hours later, the battery was off.

Help me, Anker-Wan Kenobi! You’re our only hope! How can we keep the sock going indefinitely using your products?


For something this important to know the facts, I’d email support@anker.com with the specific question of the cut-off trickle power level for this product and try to find the same question answered of the power needs of your device (sock).

My anecdotal experience is smaller Anker Powercore have lower cut off trickle charge levels, but even so they will not stay on indefinitively.

An undocumented hack is simply use the fact the Powercore has 2 ports and simply attach something which draws some power (ideally little to not waste) to the 2nd port. The additional added draining device will cause the power to deplete faster but act to keep power staying on for the whole period. Example: a small USB low strength light.

1 Like

Yeah, funny that you say that… I’ve already ordered tiny LED lights. We’ll see if this draws enough power to keep it alive!

1 Like