I've read many questions and answers in forums like here and other web sites. Most (if not all) would say that it's possible to run a laptop straight of the mains with the battery removed.
I have a Toshiba Satellite U305-7448 laptop. To reduce weight, I have removed the battery and ran the laptop straight of the mains and the PC runs fine.
However recently the computer would fail to boot up without the battery (it would start and less than 1 minute later it would die - i.e as if there is no power). Alternatively, it would start and boot ok with the battery plugged in but if I then remove the battery it would also die.
Does anyone know what is going on here? Is there a fix for this?
Check Power Options settings please and ensure not set to battery operation alone. Reset settings. Battery can be left out of the unit, as it is primarily an Alternative power source. Go into Device Manager and check "BATTERY" menu item and learn there. What does it say when it powers down on the main power? Does it give any error codes or messages?
Keep in mind that when a battery is removed from the laptop, it will slowly discharge and you must store it in a safe dry location. You will also want insert the battery back into the laptop at least once a month, and condition the battery to keep the cells fully functionable and help the laptop and battery remember how to hold a charge.
For some battery performance tips and how to condition or recalibrate your battery: