power supply - Can a faulty battery cause my laptop to shutdown even on AC line? (battery installed AND plugged in together)

Until recently, I experience something rather annoying (and troublesome) with my laptop. It spontaneously shuts down itself without any warning, it restarts. No blue screen, no hanging program, just everything is going on smoothly and the computer shuts down similar to a desktop facing power fails, without UPS.

Here's my laptop's conditions and my guess:

• It's rather new (model Asus K53SV, I bought it this time last year). Running core i5 2430M, 8GB RAM; OS Win 7 Ultimate 64 bit, SP1.


• The shutting down occurs randomly, not too frequently (may be once a week, maybe 3 consecutive days, once a day, may be 2 days OK than happen the next day,...) but recently it happened more often.


• I always use my laptop with the battery installed, and one AC line. The battery will be charged fully to 100%, then the computer states that it's running on AC line. After a few days, when the battery level drops below 95%, the charging will begin again until 100%.


• The shutting down occurs even when th battery is fully charge, and the laptop is on AC line.


• No problem with Windows after the event, I start in safe mode, then restart again to make sure everything is OK. In the Event Log of windows 7, it store faults related to "Kernel Power Failure" or something


• I use the laptop on battery once or twice a month, making the battery drain to below 10%, then charge it to 100%.


• Please don't tell me that this is the overheating problem. It's winter in here. The ambient temperature is about 17 oC, and the Aida64 report CPU & GPU temp of 46 oC, fan speed 100RPM. When I stress the CPU to test, the fan speed adapts quickly, it can reach 3800-4300 RPM, and the CPU temp never gets higher than 70 oC.

So here's the question: What unit/chips control the current between the adapter output, the battery and the mainboard? Is it the role of the chip inside the battery? Can a faulty battery the cause of the problem, e.g "the 'digital' switch back and forth" to control the current got problem?

• For now I uninstalled the battery, running on adapter only. However, due to the randomness of the shutting down, I need to check on this condition at least 4 or 5 days to narrow down the possible cause. Just don't want to make my laptop running on AC line only in such a long period, because I don't have UPS.

Any experience or explanation would be appreciated. Thanks.