Sega Game Gear - Internal chargeable battery mod

Please don't make stupid suggestions like that, unless you're wanting people to set their houses on fire.

There is no charge controller in those cells, and I doubt there's even an over discharge protection circuit.

 

oops my bad!
Those looked like standard protected li-po packages

 

A protected cell still doesn't have a charge circuit built in.

 

all the ones I've dealt with do..

 

none of them ever do.
but you're welcome to prove me wrong.

 

@3:40




@6:53







Even tiny packages have them>


http://www.master-instruments.com.au/files/tech___protected_liion_batteries.pdf.pdf

http://www.candlepowerforums.com/vb/showthread.php?169200-Photos-of-Protected-Lithium-Batteries

Some li-po batteries are even more advanced>
https://ripitapart.wordpress.com/2014/02/12/looking-inside-an-iphone-44s-battery/

 

...What you will find, is that you've proven me correct.

None of those cells have built in charge circuits, they have built in over-discharge/over-charge circuits.

If you stick more than 4.2volts onto the cell, they will simply disconnect the cell to prevent over charging.

It isn't a charge control circuit.

 

my mistake
I've charged protected cells at 5v no problem before (at a low current), my understanding is that 5v although high, is still within the upper operating voltage limit of the protection IC. It may shorten the life of the board but how would it damage the cell, as there is going to be a voltage drop, until the cell is fully charged then the protection will kick in.

 

Yeah guys, there might be one in each individual cell that cuts it off after a while, but you still need a "balance board", as they call it in the land of RC to charge it. Just like that Adafruit I posted, because balancing cells when charging is ESSENTIAL! Things like this happen if you don't! This one just had its cycle, considering it is almost 7 years old now but it is the same effect as not charging cells in balance.