2010/11/9 Paul Hartman <paul.hartman+gen...@gmail.com>: > Hi, > > I have a laptop running Gentoo (with dual-boot to Windows XP). It was > manufactured in 2004 and battery life have been consistent for all > those years. However, it sat dormant for almost a year, after which I > did a few days worth of updating to bring it up to current kernel and > ~amd64 package levels. There are two issues that have arisen: > > 1) The smart battery is not so smart anymore. It only charges about > halfway, then the charging light turns green and it stops. Effective > battery capacity is about one-third of what it used to be. From what I > understand, while Li-ion don't have "memory" like old Ni-Cd batteries, > the "smart" circuitry cannot account for power drain that happens when > the battery is not in use. Say the battery lost half of its power > while it was in storage, so the chip thinks charge is at one level > when it is really much lower. When recharging, it stops when it is > "full" even though it's only halfway there. >
The inbuilt battery circuit can account for the self-discharge, the charge on a lithium cell is proportional to it's voltage IIRC. The problem is, that li-ion cells don't like being totaly discharged (for example lying unused for a year). It's advised to charge them and only then put them into storage (and recharge every once in a while). So your battery may simply have 3 cells, 2 of which have been damaged by self-discharge, therefore you are seeing only 30 % of the previous capacity. Br, Maciej Grela
