Internal Battery
 

Anyone know if the battery life is extended if you don't disconnect from the mains every night?

As far as I remember the battery is used to power the clock etc when the machine is turned off, ie via the switch on the machine , if it is still plugged into the mains at this point it makes no odds the battery is still used.

Yes, SLF999's right. It's just a 3 volt lithium battery which runs the clock and costs about £2.49 to replace at Radio Shack. You can tell when it is about to die, the clock runs slow and eventually you will get a CMOS checksum error message on startup. Mine went a couple of weeks ago after about four (or was it five?) years. It's probably a CR23032.

For what it's worth, the documentation that came with my Dell Dimension desktop says that maintaining mains power does increase internal battery life. Maybe it's just a Dell thing. Anyone else seen any manufacturer's suggestions re this?

Dell is telling the truth. The battery is not chargeable - it contains a diode to prevent charging in fact. But the fact that there is power on the battery (diode) there will be little/no current drain either - so life will be improved.

sanjosebaz & jetfour....... .. .It was the Dell paperwork and a similar statement in an old copy of 'PC's for dummies'that prompted me to ask the original question.Seemed unlikely there would be any real gain,but maybe there's something in it ,however small.

I suppose the real point is that there is very little current drain anyway, so the battery life is very long - even if you never put mains power on the PC. But there will definitely be an improvement if you reduce the consumption to near-zero, as you will be by powering up!

Battery life is just not worth worrying about unless it is faulty. I have until recently been working with machines built in 1990, about half eventualy had battery problems but we are talking 386sx machines. Most equipment will be obsolete before the battery goes.