It will only charge as fast as the output of the power bank.

this assumes it's not a dogshit quality power bank

He's saying if you plug the charger in it can transmute the energy into work, meaning when you exit the room you may come back to finding it sitting on the counter unplugged. As your partner wouldnt have wanted it to put a hole in the roof so they unplugged it and put it on the counter.

So did that dog chewing through one of these in the other post recently, subsequently broke the mattress and house apparently, haha

Yep. State of charge is almost entirely voltage based.

As a battery loses charge, the voltage sags.

What's happening in the OP is that the batteries are getting a voltage bump, likely from the conversion to/from 5v on the output and the conversion back to battery charging voltage on the input (or the thermal/internal resistance is changing).... One of those things.

Either way, the conversions are not 100% efficient, so basically all this does is turn your battery bank into a heater, slowly sapping the power away from it as heat until dead.

With phones, it can also be battery degradation, that the voltage drops off at a higher "state of charge" level than when the battery is new.

Voltage sags can also be induced by load. If you go from a high drain state on your phone to a low drain state (say, going from playing a 3D mobile app to idling at the lock screen) the state of charge % can actually increase.

Cold temperatures can also increase the internal resistance and cause batteries that are not fully discharged to stop operating as well, only to work again after being warmed up.

Current battery tech is wild, and the state of charge indicator of voltage can be extremely inaccurate.

Just like at work: Forward office calls to your mobile. Forward mobile calls to your office phone.

Get your work done until everybody finds out and starts wasting your time again 😂

I imagine plugging a powerbank into itself just causes a short circuit. Detecting that isn't the most uncommon thing fafaik.

Something something ground loop detection, maybe.

You either have a ping before connecting and if you get a response don't do it. Or you send some high frequency wave additionally to the power. You can detect that signal and then stop accepting the power.

Basically like ethernet over powerlines work.

was around 10 years and Anker

Nail it to the side of your house, in the sunlight, for a totally free charge from the sun

You're welcome, now you don't need to risk your own phone in order to know :p

Those chargers are really dangerous. It is technically possible to recharge a disposable alkaline battery a few times, but you're never going to get more than a half charge, and it will fuck up the internal chemistry turning each battery into a tiny potential pipe bomb.