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do the protection circuits in batteries handle charging too? Answered

do the protection circuits in rechargable Lithium Ion (and etc.) batteries stop the battery from charging once its fully charged?
im just wondering because i plan to repair a palm pilot that cant charge on its own.


if they overcharge they fuse off

Most of these protection circuits for a single cell have a MOSFET to switch the power OUTput on/off. So depending on the cell voltage and/or current sense resistor voltage and/or temp sensor voltage, the control circuit can cut off the cell's output. They can't do anything to stop the cell from overcharging. About the only thing you'll typically see that could somewhat protect the cell from grossly overcharging is a fuse.

The easiest way to charge a cell is by getting an IC to charge from 5V/USB. There are tons of IC's out there made to do exactly this.


6 years ago

I have had a bad experience with 12V DC lithium packs protected by a package
built in uP watching all the individual cells.
It ( the uP ) couldn't handle series cells worth a blue dam.

Most protection circuits I have experience with use temperature as the tip-off
over overcharging.