ACPI battery charge strange, %-age decreases even on AC

[Benedek Frank <linux@celifornia.com>]

Hi

My Sony Vaio got a new (non-OEM) battery. It works good, gives me a little 
over 2 hours of battery time. However, when I charge it up and leave the 
laptop plugged in for days, it will start to loose its charge. About 1% in 
two days. This goes as follows:

I charge it, it is 100%. Two days later, it will show only 99%, even though in 
this 2 days, the AC adapter wasnt unplugged, not even for a second. Then, 2 
days later it will be 98%. Now 98% for me. Before a week ago, when it 
happened the same way, at 99% I tok it off the AC, let it use the battery 
completely around 2 and half hours, and then recharged it. It was 100 and 
then it went down to 99 again in 2 days. Why is that?

Here is the /proc/acpi/battery/BAT1/state

present:                 yes
capacity state:          ok
charging state:          charging
present rate:            0 mW
remaining capacity:      18630 mWh
present voltage:         12613 mV

Here is /proc/acpi/battery/BAT1/info

present:                 yes
design capacity:         18850 mWh
last full capacity:      18850 mWh
battery technology:      non-rechargeable
design voltage:          155 mV
design capacity warning: 0 mWh
design capacity low:     120 mWh
capacity granularity 1:  0 mWh
capacity granularity 2:  10 mWh
model number:
serial number:
battery type:            LION
OEM info:                Sony Corp.

THanks

Bence