Upon battery insertion the battery manager board, if working, momentarily test charges the cells and looks for approximately
3V=
If this is not met charging is disallowed and the battery would not be recognized nor connected to the laptop for discharge. Of course if the battery manager itself was toast that would do it also.
Cells that have been discharged down to the normal 3.0V cutoff point normally rebound to about 3.4V or more within minutes of being disconnected. Cells that measure much below 3V are approaching a dangerous chemical state internally for later internal shorts should they be subsequently recharged and are best never used again.
The laptop batteries commonly use a series parallel configuration that requires a degree of cell matching to be safely charged and discharged. Cells from different manufacturers use different forms of carbon inside and have correspondingly different charge control parameters programmed into the battery manager EEPROM. There needs to be sufficient current sharing within a paralleled group so that the high current intended for the paralleled set does not inadvertently flow thru just one cell (as it could from mismatching or if cell strapping fails) and make a bomb. To make the gas gauge work right the groups need to have reasonably comparable amp hour capacities and internal series impedances. So recelling especially using used cells requires instrumentation, bench measurements, cell matching and a properly working battery manager, not just flawless connection technique rewiring charged cells. If the safe operation zone specified in the cell manufacturer's datasheet and application notes is exceeded for any reason you have a potential incendiary bomb that can also vent boiling alkali steam and blind someone.
3V=
If this is not met charging is disallowed and the battery would not be recognized nor connected to the laptop for discharge. Of course if the battery manager itself was toast that would do it also.
Cells that have been discharged down to the normal 3.0V cutoff point normally rebound to about 3.4V or more within minutes of being disconnected. Cells that measure much below 3V are approaching a dangerous chemical state internally for later internal shorts should they be subsequently recharged and are best never used again.
The laptop batteries commonly use a series parallel configuration that requires a degree of cell matching to be safely charged and discharged. Cells from different manufacturers use different forms of carbon inside and have correspondingly different charge control parameters programmed into the battery manager EEPROM. There needs to be sufficient current sharing within a paralleled group so that the high current intended for the paralleled set does not inadvertently flow thru just one cell (as it could from mismatching or if cell strapping fails) and make a bomb. To make the gas gauge work right the groups need to have reasonably comparable amp hour capacities and internal series impedances. So recelling especially using used cells requires instrumentation, bench measurements, cell matching and a properly working battery manager, not just flawless connection technique rewiring charged cells. If the safe operation zone specified in the cell manufacturer's datasheet and application notes is exceeded for any reason you have a potential incendiary bomb that can also vent boiling alkali steam and blind someone.