I've been using my Dell XPS M1330 very successfully for the past 3 years with no problems at all. However, the battery shipped with the laptop was no longer optimal, and was only lasting 30 minutes. Time to buy a new battery, I thought.
The Dell branded batteries are so expensive, well over £100, that I thought I'd try out an unbranded battery. Although the battery doesn't fit as well as the Dell original (it takes a bit of wiggling to get it in and doesn't click into place properly) it seemed to work fine and gave me 90 minutes running time, so initially I was happy with the purchase.
However, within a few days I noticed that my hardware clock was no longer working! I run Linux and Windows Vista, and neither operating system were able to read or write the hardware clock anymore. They would start up with dates anywhere from 2000 to 2012. Linux would hang running 'hwclock' and needed Ctrl+C to boot up properly, and both Linux and Windows Vista would hang when shutting down and need a hard power-off. Looking in the BIOS, I can see that while I am able to adjust the hardware clock, it does not advance. It is no longer ticking.
Investigating this further I am 100% certain that a permanent hardware fault has been caused by the introduction of this unbranded battery, and I am very VERY disappointed to say the least. I was hoping for at least another 3 years of life out of this laptop, now I just don't know what to do. Reverting to the old battery or using the mains power adapter makes no difference, the hardware clock is permanently broken.
I have written a letter of complaint to the supplier, and I hope for their own sake they have some kind of insurance that I can claim against! This is a shockingly poor product and should be taken off the market.