I have a inspiron 1525 celeron laptop with vista. I bought this a year ago. These are the chronology of events and problems with my laptop.
Jan 09: Time synch issues. Played around with timeserver but was never able to resolve this issue
Feb 09: I get warning saying that the battery is charging fine but I might have to replace it soon.
Mar/Apr 09: Battery charges only 4%. It can't charge anymore.
May 09: My battery doesn't charge anymore. A orange light blinks at battery charge indicator.
After few days I get a error saying the computer cannot start as time issue. I searched online and found that replacing CMOS battery would help. I have replaced the cmos battery and it started working fine.
Jun 15 09. My laptop doesn't start anymore and is giving the same time error. Replacing cmos battery resolved this issue. Should I replace it again.
I have opened the case again. Removed cmos and put it back after a minute. It works now. The last time I did it, it didn't ask me to set the time. This time it did. I see that the time works fine even after many restarts.
Yep the main battery is dead. I'm contemplating if I want to spend more money on this laptop .
Reference CMOS battery.
They should last 3 -> 5 years. The problem is self life. The original battery could have been an off-the-self and your 1st replacement could have been an OLD battery nearing its end of self life. Look for a date code on battery. Also if this CMOS battery prematurly fails I would suspect your cmos chip is drawing excessive current.
Last year I finally had to replace the cmos battery in an "Old" laptop (Compac AMD 1.2 GHz laptop) - But it was over 6 Years old. NOTE on some of the newer Laptops the CMOS battery is soldered in - ouch.
As to main Laptop battery.
Again, with proper maintenace They should also last much longer than 1 to 2 years. I'm still using the orginal battery for the 6 yr old compac ( did buy a new one a yr ago).
About every 3 Mon (me - 6 Mon) they (NiCd and or Li-ion) should be completly discharged and recharged. Also do not leave the battery installed when the laptop is not going to be used in the next two to three days.