Laptop mains adapter gets hot

  iamalipaul 11:22 20 Oct 2009

Hi all

I bought a Compaq laptop for my daughter to go to Uni and before she went, I did notice that the mains adapter gets quite hot. I have advised her to run the battery down before plugging into the mains to prolong the battery, but I'm sure it will need to be mains powered for long periods while she writes essays, surfs, facebook etc... So:

1. What is the best way to prolong the battery?
2. I know the adapter will get warm, but how warm? about the same as a hot mug of tea.

I ask now because Ive had to replace her sister's laptop adapter after 2 1/2 years (Gateway), and I know that one is permenantly connected because the battery is shot.

  dms_05 11:34 20 Oct 2009

Every laptop power supply I've ever owned runs hot, if the battery has been depleted and needs recharging, at the same time as the laptop is in use, then it gets very hot. Personally I leave the power supply plugged in and turned on whilst I'm using the laptop near my mains supply.

  Stuartli 12:53 20 Oct 2009

As dms_05 states, mains adapters do get quite hot.

Also, if left in the mains socket but without being attached to a laptop, mobile phone or whatever, they still consume electricity. See:

click here

  oldbeefer2 13:06 20 Oct 2009

best way to prolong the battery? Leave it out and run on mains unless batt really required.

  iamalipaul 21:54 20 Oct 2009

Are there any issues to running a laptop on the mains without the battery?

  mooly 07:29 21 Oct 2009

"Are there any issues to running a laptop on the mains without the battery?"

Personally I would never do this... the charging circuit and logic "expects" to see a battery in place at all times.

If a power failure were to occur then the laptop may suffer corruption of files on the HDD. It's just like pulling the plug on a desktop PC... you NEVER EVER do it.

Batteries unfortunately deteriorate from the day they are made, and you may as well get the use and benefit from them.

Modern laptops manage charging very well, the battery isn't continually charged as many think, it is charged to a nominal 100" and then all charge current is removed and (if the battery isn't used) it is allowed to self discharge at which point after a few days the charging circuit will "top off" the battery back to 100 %

How to prolong the battery.
If you can use mains whenever possible.
Use the battery occasionally with an odd full discharge to nearly the cut off point.
Try and keep the laptop away from heat.

And yes adapters run hot, make sure it is free standing in air.

  peugeot man 08:35 21 Oct 2009

Assuming the mains adapter has a plug and lead to connect to the mains socket rather than one that sits on the socket you can help keep it cool by NOT placing it on carpet or furniture.

For example in my dining room I place the adapter on my glass top dining table, in the kitchen I put it on the tiled floor.

Any surface that absorbs heat will act as a heatsink and help keep it cooler.

I consider it good practice to allow the laptop battery to completely discharge before using mains.

  oldbeefer2 08:46 21 Oct 2009

Sorry, I have to disagree - there is nothing wrong with running a laptop without battery (other than risk of losing data if the mains fails, but we all risk that when using a PC - not a frequent occurence). Some sensible advice here click here

  iamalipaul 09:42 21 Oct 2009

Thanks guys

I've ticked the resolved box as my questions have been answered.

It seems there are pros and cons to the battery in/out and steps you can take to prolong the life.

Just means that my daughters will probably have to replace battery/adapter (It'll be me paying!) in the future.

  Stuartli 09:45 21 Oct 2009

Glass is not a good conductor of heat hence the efficiency, for instances, of greenhouses.

It's the light that the glass lets through that provides the heat.

I would have thought too that a tiled surface would not be a heat sink for a laptop - you are probably benefiting from the open area around the machine.

  woodchip 11:15 21 Oct 2009

you should not run battery down as it does not do the battery any good on new type Laptops. do not let it drop under normal use if used as Desktop below 25%. If the Laptop is new I would take it back for it to be checked out My HP only gets Warm not Hot. Sounds like its not the HP Compaq charger

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