I bought my x120e about a month ago, and it's been great since then, but recently I've had issues with the battery. When I charge the battery to 100% and then disconnect the AC adapter, the battery is fine for one or two hours and the charge will decrease at a normal, steady rate (indicated by the percentage). However, when the battery gets to 75-80%, it then suddenly jumps down to 10%, and I get a message that I have to charge the laptop or turn it off. When I plug it in and start charging again, the battery charges at a normal rate from 10 to around 40%, but then the same thing happens and it jumps up to 100%, telling me it's fully charged. Generally, I would be happy with such a quick charge, but in this case the battery isn't really fully charged because it suddenly dies after I disconnect it from the adapter. Even if I leave it to continue charging at 100%, the same thing happens.
So, I was wondering if I could do something to fix this on my own, or if I should just send it back on the one-year warranty. Please tell me if I was unclear in describing the problem, and thanks for any help/suggestions!