My 3540 is nearly 2 years old.
about half a year ago, my adapter went bust, so I changed it to one of those universal ones. The original adapter's output was 20V, 4.5A. The universal one is 19V, 4.74A (or so it says anyway...).
Then the strangest thing happened; When the charge was between 20-40 pct., and running on battery, the computer just switched off - just like that, no warning. So i plugged in the adapter and recharged the battery - only to find that this was standard practice for my computer from now on when running on battery.
Then after about three months the coumputer would switch off, if I tried to remove the AC plug - even with the battery still in.
As if this wasn't enough, even with AC plugged in, then the computer wouldn't start at all! So I sent it in, got it repaired with the remarks that the BIOS was updated, and the CMOS was reset. This only made the computer start again, but didn't solve the problem with the battery not charging and the computer not willing to run on battery alone.
Then the battery icon (win vista) fluctuated between low and high values at random, as if the charge couldn't be determined. And now the icon just shows "0 pct left, connected, charging". But it isn't.
So the question is not so much wether or not to invest in a new battery, but more about the nature of the problem: How did this start? Was the universal adapter's 19V not enough to charge to battery? And why did the computer switch off when running on battery with still 20-40 pct left?
hope you guys can help me out...