Use laptop without battery?

The battery on one of my ancient laptops has died. Is it safe to run the machine without a battery, just using the mains? I've heard that laptops shouldn't be left plugged in even when switched off and I now unplug my other machines every night. Just interested in the technical explanation for this.

It should be fine to use a laptop on mains without the battery.

As far as unplugging over night this is usually due to potential fire risks of any electrical product - often caused by the power supplies. Actual events are relatively rare but the problem with something happening at night is you are usually in the house and asleep therefore in much more danger than with a normal day time incident (where you are either out of awake to notice something is wrong).

There are those that will suggest unplugging all electrical items when not in use. Personally I don't but I do understand that it could put me and my property at risk.

One reason to not leave a laptop plugged in is if the battery charger keeps trying to charge battery when full (or dead) it becomes a big fire risk (applies to all devices with battery charging, especially lithium based batteries) .

I haven't heard of issues running laptop without battery, I have seen advice to actually take battery out if not using it as heat from laptop could age battery - I used to run laptops without battery (charging them periodically) - I can see a couple of reasons why you might want to keep battery it - one is poor PSUs may have relied on battery to provide stabilizing (unlikely in laptop) or the battery case is actually important to the structural rigidity of the laptop or required to keep an air gap under case etc.

If it was me I'd run it without battery

Been running my laptop without a battery for 99% of the time over many years without issue.

Modern chargers should significantly dial the power back once the battery is full. The modern batteries have a protection circuit that will stop them taking charge once full. The time it becomes dangerous is when the circuit fails - it is a low risk but still a risk.

A lithium ion battery and charger in working condition will not continue taking charge after full and are not a fire risk. However, as with any electronics if something has failed then there is a risk and therefore the general safety advice not to leave electronics on charge when in bed.

Edited by ian72 (Fri 03-Jun-16 07:19:54)

Thanks for that. I wonder if security will let you take a laptop without a battery onto a plane - is it the battery that they are suspicious about or other parts? This particular machine has accompanied me all over Europe (it's an HP Pavilion Mini) as it doesn't weigh a lot and after I added extra chips to get 8GB RAM it performs well.
It's due to fly again soon, so here's hoping some jobsworth doesn't say 'no computers without a battery allowed on the plane'.

At the security checkpoint you have to take a laptop out of your bag and put it through the scanner separately and they may ask you to turn it on to show it works (which generally will require the battery to be installed). So, whilst you should be able to, in order to prove the laptop is a laptop and not been gutted to create a bomb may require it to be powered up - and they may not allow you to plug into the mains to do so...

EDIT : One sentence was not even understandable to me!!!

EDIT 2 : A somewhat dated article (unfortunately from the Daily Mail) about powering devices at check in here

Edited by ian72 (Fri 03-Jun-16 09:29:50)

Some of your advice no longer applies in my experience.

All they do now is ask that laptops are removed from cases and placed in a tray to run through security.

I've never been asked to power anything on (and never been asked why I have so many devices, e.g 2 laptops and 2 iPads and 2 iPhones).

Not applicable to you, but maybe of interest to any Apple MacBook users who are reading this- running a MacBook without the battery will cause it to downclock by 50%.

The reason is that the power adaptor can't provide the maximum current that the MacBook is capable of drawing if everything is running at full chat, and relies on the battery to "fill in the gaps" and thus avoid crashes.

Apple used to have a note about it, but it's been pulled for some reason (maybe it doesn't apply to later models?), but Googling will bring up plenty of comments about it, eg here.

I did say "may ask" - I haven't been to the US for quite a while and they tend to be strictest at the moment so didn't know if they might request it to be turned on.