Unable to start laptop from battery

[NineToTheSky]

My laptop (Fujitsu Amilo) powers up from mains power, but not from battery only. The battery isn't dead, because after powering up, if I remove the mains cord, it will run on the battery with no problems. The battery discharges and charges as it should.

Any ideas as to what the problem is?

[Dewey Finn]

It may be that the computer needs more current to start up than to keep running, and the battery is old enough that it can't provide the extra current.

[NineToTheSky]

Originally Posted by Dewey Finn

It may be that the computer needs more current to start up than to keep running, and the battery is old enough that it can't provide the extra current.

It is an old laptop, bought in 2004. Is there anything I can do - apart from buying a new battery? What you say makes sense, but I've never heard of this before. Is it common?

[dracoi]

A two-year-old battery in my HP laptop got to a point where it couldn't provide enough juice to keep all of the systems going, especially if I was doing something intensive like playing a DVD. The power to the screen would cut out and I'd have to put it to sleep, then wake it up to get it back.

It didn't have any problems starting up, but the general principle of reduced potential output is true enough.