MP3 player gets pretty hot when plugged into USB to charge

[lordvader88]

I find it annoying how much energy gets dumped into this cheap little MP3 player to charge it's Li-ion battery. IDK how it charges (compared to other Li-I batteries), or what the circuitry is. IDK if it keeps trying after it's topped up. It just doesn't seem right for it to use so much energy that's just getting dumped into heat.

I'm imagining it's passing 5V across some diode after charging is over, rather than shutting it off.

There's no question here, I've had it apart, I should look up the MCU in it again, it's just annoying. Makes me worry it's going to fry itself, the case probably gets to 45deg C (125F iirc)

[james_s]

Most of these things have small linear charge controller ICs, chips specifically designed to charge Li-ion cells. Getting warm is normal, however if you've noticed it getting significantly hotter than it used to then that could be a problem.

[Raj]

Lets force it to take up less power by limiting current to it by making our own cable for it.

[lordvader88]

Yeah I guess it's not 50C, but it just seems so warm and the battery is supposedly done charging.

Maybe it's just the LED backlight, that stays on the whole time it's plugged in. These cheapo MP3 players don't last long anyways.

I've been walking around with earbuds for years know......how many days worth of my life, have I wasted trying to keep them in my ears ??