How to charge / discharge a Li-ion laptop battery

Jen_31

Hi

I have a Laptop and recently the little power icon on my toolbar is missing. I did fix it, but it's gone again!. I was on my pc, and the little warning of low battery indecator didnt appear, my laptop switched off.

I used to have a nicad battery ( i think) in my old laptop. It needed to be basically left tto go low, then plugged back in again. Something called `memory effect` .

I have just did a battery check, i know have a hp laptop, and it says my battery is weak?. Im unsure if this is because my little icon on the toolbar is missing?.

Basicall. i read about Li-ion batteries and it says that they dont get memory effect, and that they dont need to be left to go low powered, they need a little discharges, then charging back up?. Then letting go completely flat once a month?.

If this is right, i havent been doing this. I thought i was doing the right thing by leaving it go low, then plugging in. I b****ed my last laptop battery by leaving it plugged in all the time, and im just thinking i might have b******d this one up, by doing what i thought was right :rolleyes:

So how do i charge this battery, do i let it go low, say 50% then plug it back in again?. It's all very fiddley isnt it?.

Thanks for any help, and i hope i havent killed my battery with doing what i though was right

Leopard

You might find some of the information and links here helpful.

It's Apple's advice but the principles are the same.

Nothing is worse for a battery than leaving it constantly on charge; you need to keep the cells inside it moving and give them some exercise. :j

Jen_31

Leopard wrote: »

You might find some of the information and links here helpful.

It's Apple's advice but the principles are the same.

Nothing is worse for a battery than leaving it constantly on charge; you need to keep the cells inside it moving and give them some exercise. :j

Hi, thanks

Do you know at all if it's possible to run a laptop with the battery out, with the ac adaptor plugged in?. It's just, i have the laptop in my bedroom and never take it anyway, so it may be better for me to take out the battery and just use the ac adaptor?.

720

Yes, this is possible on most laptops (If not all), this will not damage the laptop in anyway either.

fwor

Most will run with the battery not installed, though you are of course at more risk of losing what you're working on if you get a power cut.

If you do that, don't forget to plug the battery in every couple of months to keep it topped up.

thescouselander

There are a lot of misconceptions about Li-ion batteries due to what people used to do when Ni-cad technology was around. You need to treat Li-ion/Li-po batteries differently.

First of all never run them down too far - this can damage them. I never let mine get lower than 30% charge remaining. Use the battery regularly to keep it good and if you're not going to be using the battery for a while its best to store it at around 50% charge in a cool environment.

Jen_31

thescouselander wrote: »

There are a lot of misconceptions about Li-ion batteries due to what people used to do when Ni-cad technology was around. You need to treat Li-ion/Li-po batteries differently.

First of all never run them down too far - this can damage them. I never let mine get lower than 30% charge remaining. Use the battery regularly to keep it good and if you're not going to be using the battery for a while its best to store it at around 50% charge in a cool environment.

ah thanks, yes i used to have a ni-cd battery, and it went weird, as i had it plugged in all the time as the battery was very poor, and made by advent :rolleyes:

i'll do all of the above^

Will maybe give it a go with no battery in , and the 30% thing if i do keep the battery in

:T

RobTang

if you are just running off the AC make sure your cable is secured someway to the laptop, accidently pulling out the cable while you are working isn't fun. some systems dont like instant offs either.

Also DONT top up your battery if its in long term storage, leave it at 50-75% charge and stick it in the fridge (or somewhere cool) and it wont discharge any lower for a long time.

Leopard

Jen_31,

Even if the laptop permits it (not all do) it's usually a bad idea to run it with no battery at all inside it.

Some laptops use the battery as part of their heat dissipation system. Remember, also, that the terminals inside the empty battery bay will be live. And there's the possibility of tiny objects (including insects) getting into the computer through the battery bay on some models.

If you've still got the knackered battery, though, it could be a good idea to put that inside it (instead of leaving the battery bay empty) and then run it permanently connected to mains power. The snag with that is that this leaves you vulnerable to power cuts.

One of my laptops I do leave almost permanently connected to power (in a docking station) with a knackered battery installed. When I remove it from the docking station (which involves shutting it down, to do it wisely) I put a healthy battery into it and restart it. This works well, but the docking station is connected to a UPS (Uninterrupted Power Supply) device, so it is protected from power cuts.

Batteries can last a surprisingly long time if they're properly looked after. I'm writing this on a 2002 vintage Apple titanium PowerBook with its original battery installed and its uptime between charges, with Bluetooth and wi-fi running, is about one and three-quarter hours. I do, however, rotate it with two or three others of the same type whose hosts met with premature ends!

John_Gray

Leopard wrote: »

Even if the laptop permits it (not all do) it's usually a bad idea to run it with no battery at all inside it. Some laptops use the battery as part of their heat dissipation system.

Conversely, my ancient Advent laptop will overheat and power off after about 20-40 minutes if the battery is left installed! Yes, even when the fans are completely clear of dust, and it is propped up on ¼" high 'feet', for air cooling. The battery ceased to hold any charge ages ago. The only way to use the laptop reliably is to take the battery out, and then it will run on mains for days at a time without problems.

However this may say more about the 'quality' of Advent laptops than act counter to your thesis...

Leopard

It could be that, with some laptops, the heat generated by trying constantly charge a dud battery builds up, whereas some others recognise that it's a hopeless endeavour and stop trying.

In a metal laptop that has been designed to use the casing as a heat-sink, the battery itself plays a role in transmitting the heat evenly around and across the area adjacent to the battery bay.

I guess one just has to experiment and find out what works best for one's own laptop!