I have an old dell which has been extremely reliable, but recently the battery got fully discharged, when i powered it up the next day it wouldnt run on the battery (fair enough as it was flat as a pancake) but when i attached the mains powerpack i got the indication 0% remaining (charging) when you look at the power icon on the taskbar however the battery never charges or gets past 0%, if you remove the battery none of the lights on the power guage come on, ive tried another (untested) battery and same result, i checked the voltages on the battery connector internally when its connected and seem to be getting on Pin7 (counting left = pin1) to right Pin 7 i see +17.5v from Pin7 to Pin 1 (gnd).
Does anyone know if these battery packs have internal circuitry for charging regulation, or are they simply a Li-Ion cell?
The battery is a BAT-30IL (14.4v 4500mAH, 2.5a charging current). P/N on the PSU 0009878C-12961-8AT-0619.
Also there is a PSU PCB inside the laptop, this appears to generate all the DC rails for the laptop, ie +5, +3.3 +12 etc
and standby voltage rails, this appears to feed the battery but im still unsure if the fault is with the battery or the internal PSU pcb in the laptop or perhaps neither?, i read somewhere there is a battery calibration routine, and i wonder if this might somehow have got screwed up? if anyone has any schematics of info on this it would be greatly appreciated as i have so far failed to locate the problem!