Fire hazard speed run
I don’t think it would it be too bad since it’d have a current limiter would it?
Yeah, so I think it’d be fine, since I’d think the charge limit would be about the same as the discharge limit of the power bank. It would heat up a normal amount for charging and being charged at the same time, but I don’t think it would melt down or anything. It’d just drain slowly over time.
Jokes aside, this is something an astonishing number of folks know less than nothing about.
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.
AFAIK, those things estimate charge based on voltage. If a battery heats up, it’ll have higher voltage. Not necessarily for a good reason…
Is that why they’re so inaccurate that they always die around 20-30% and never charge to 100%? I figure that phone battery meters are accurate cause they can track usage habits, but how would you do something like that with a power bank?
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.
My powerbank just detects that it is connected to itself and does jackshit.
I wonder by what method it does that? put out a pulse code on the power out and look for it? Some USB cables don’t actually carry the data lines through, so.
I imagine plugging a powerbank into itself just causes a short circuit. Detecting that isn’t the most uncommon thing fafaik.
Probably just sends a number as data, and if it gets it back then doesn’t charge.
You’re right that some cables don’t carry data, but most do and as long as the cable that comes with it does then it’s going to be fine for 99% of cases.
There’ll often be a way to break it like going through a USB hub, but most people aren’t actively trying to damage things. I can see people wrapping the cable around it and plugging both ends in to stop them flapping about though.
Firefighters hate this one easy trick!
