Laptop batter drain while plugged in

[dan.in.haruno]

I hope you can help, I'm kind of at a loss. I have an Acer Ferrari 3200 laptop (very nice machine, got it last November and haven't had any problems until about 2 weeks ago). The battery has started to drain even while the unit is plugged in. About two months ago I moved from the US to Japan, so there is a wall power difference, but I thought that a US adapter should be ok since the Japanese output (125v where I am) falls into the adapter range of 100-240v). I originally thought that the problem was the adapter, but I have replaced it and I'm still having problems. Could it be a battery problem? Any help would be appreciated.

 

[Tedster]

what is the hertz difference b/w japan and US power?