In my very recent experience, they don't ask.

In reply to a post by ian72:

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.

Removable Batteries are also subject to risk of damage and damages batteries can cause fire risk even if charger is working correctly - risks are generally very low, potential consequences very high so worth being a bit cautious.

What ever you do - don't assume all new chargers and batteries are modern with proper safety precautions designed in, especially if from cheap sources - i.e. that cheap no brand high powered light and charger from east should be treated more cautiously than a main stream laptop's charger and battery.

Some newer laptops and I have a Lenovo model in mind allow you to lock out battery charging as say a 65% max charge allows the battery to last longer particularly if mains is used as the main power source. ie it's not said to be good if it's kept at 100% charge if hardly used on battery.

In reply to a post by ian72:

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...

Hi ian72,

The battery to my laptop died after 1.5 years but I have been using the computer with a power supply. The battery is still connected to the laptop because I am afraid it will get dust inside?
I travel alot with my laptop and have never been asked to turn the computer on so far, but would security confiscate it if I could not boot it up using only the battery? This is, if they prohibit me from using a power socket for the power supply.

Also, the dead battery is always connected to the laptop and I never remove the power chord when going to sleep. Is this still dangerous, even if the battery is dead and not capable of charging?

In reply to a post by Vorlon:

Some newer laptops and I have a Lenovo model in mind allow you to lock out battery charging as say a 65% max charge allows the battery to last longer particularly if mains is used as the main power source. ie it's not said to be good if it's kept at 100% charge if hardly used on battery.

Yeah, I've noticed that on my laptop.

Thought it was a fault at first, saying " 60% not charging " when plugged in, or similar percentage.