Incredibly cheap retro handheld console, battery management

 I bought a couple of those on amazon for 20Euro (yes 2 for 20Euro, one blue, one red)



They are incredibly cheap, and surprisingly not crap considering the price.

The screen in particular is not too bad. Looks like 2.8' 320x240 screen in parallel mode.

 My goal is to put an esp32 inside later on.

Let's have a look the power supply / battery.



The schematic is more or less that one : 


And unless i've missed something, yes the battery is connected to USB through a diode

That's it.

So since usb is 4.5....5.5v, the battery is connected to 3.9.....4.9v

At best, it relies on the battery protection circuit (if there is one)

And if the battery is severely discharged, the charging current will go near 1A, way too much

for those cheap batteries.

At worst, it will severely overvolt the battery, which will kill it very quickly






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