will it damage the battery

ghgh · 26 Sep 2006 at 17:36

..if i leave a laptop on for 12 hours a day with the battery still installed but using power from the ac adaptor? as my mate said that 24/7 use is best with the battery removed as constantly topping up the battery cells can damage the battery? is this right, so i`m wondering if 12 hours a day is too much with the battery installed.

off topic but does anyone think a laptop subforum would be good? I`ve seen a lot of posts about laptops recently in general hardware.

thanks for any help
ghgh

Steve09 · 26 Sep 2006 at 17:38

Never heard that before, just do it

Minstadave · 26 Sep 2006 at 18:34

I always thought you were meant to take out the battery if you were using the mains.

KnightStalker · 26 Sep 2006 at 19:43

Well its done it to my Vaio lappy, although when i contacted Sony, they said it shouldnt happen at all and is perfectly safe, so they are sending me 2 new updated batterys, as it happened within 4 month of owning it.....but Sony says its fine...but after my little encounter i think ill remove them when connecting to mains, unless im charging them.

Cyber-Mav · 26 Sep 2006 at 23:11

constantly running the lappy from the mains does effect the battery, it then tends to hold less of a charge. but it can easily be fixed by deep cycling the batter a couple of times. i have a client who has swapped out a few machines now for lappys since they have built in 'ups'

Minstadave · 26 Sep 2006 at 23:21

Cyber-Mav said:
but it can easily be fixed by deep cycling the batter a couple of times.

How do you do that mate?

Steve09 · 26 Sep 2006 at 23:50

Minstadave said:
How do you do that mate?

You go to a Chip Shop, ask if you can use their batter machine, deep cycle it in their and it will come out all battery

Mr. Brightside · 26 Sep 2006 at 23:51

Two things about having the battery plugged in all the time that contribute to long term capacity reduction; first, is the extra heat due to it being attached to the system. Secondly, the best storage level for lithium ion batteries is 40%. So ideally for optimum long term storage, you would discharge a battery to ~40% and stick in a freezer.

I've had an Inspiron 6000 for over a year now and 90% of the time that it's at home, it's on mains with the battery in.

Basically it's better if you do remove the battery but it doesn't really matter if you can't be bothered (I can't!).

null

Joe42 · 26 Sep 2006 at 23:58

Minstadave said:
How do you do that mate?

I think this is lithium ions suffering from memory effect, which isn't supposed to happen but probably does a little bit.
What you do is charge it fully, discarge it fully, repeat a couple of times and this will both recalibrate intelligent battery chips and eliminate any memory effect.

As for leaving laptops on mains with the battery in, unless its perminantly trickling the charge circuit should go off when the battery is charged and remain off. Older batteries will discharge themeslves a bit so they will be topped up again but as lithium ions don't officially suffer from memory effect this should not be a problem. Even if it does constantly trickle it this will just be dissipated as heat and should not cause a problem.

These batteries only last about 3 years anyway, regardless of usage, so i doubt that one would fail prematurely due to being topped up in that time. However, laptop battery technology does seem to be a little crude, with exploding batteries, batteries loosing their charge etc.

null said:
Basically it's better if you do remove the battery but it doesn't really matter if you can't be bothered (I can't!).

null

The reason i don't bother is all lithium ion batteries die after about 3 years, regardless of what you do to them, and i can't see wear and tear of any sort killing it before then.

ghgh said:
off topic but does anyone think a laptop subforum would be good? I`ve seen a lot of posts about laptops recently in general hardware.

Its been suggested a few times, i personally think the sff forum should change to laptops and sff since they are extremely similar. I think Yewen was keen on having a laptop forum iirc before he became a don, i'm supprised nothing has been done.

Corasik · 27 Sep 2006 at 02:56

Yep, 3 year life on LiIon is about right, and the chargers must shut down when the battery is full, or it will overheat, and explode.

Older NiMH batteries also need their chargers to shut down, as trickle charging an already full NiMH causes cell damage (Which some people put down to memory effect, but its actually heat damage from being overcharged). Deep discharge on a healthy NiMH is not advised, these cells dont like being discharged below 1 volt. If your battery is good, then its not ideal to deep discharge. On the other hand, if the battery is already 'bad' then it wouldnt hurt to try as a last resort, but dont try 'conditioning' a NiMH battery as 'preventative maintainance'.

The oldest NiCAD batteries do get memory effect, and should be fully discharged before every charge, but they can be trickle charged continuously once they are full. Its just bad to 'partially' use a NiCAD, and then put it back on charge before it was empty.

Lead Acid batteries should always be recharged, as the acids will eat away the battery if its not in a charged state.

hardc0re_tid · 27 Sep 2006 at 13:03

i was told it will reduce the length of the battery

mine used to last over 1.5 hours, i used to use it on the mains all the time, battery wont even last 1 hour now!

i have an Acer 1350xc w/ standard battery

Joe42 · 27 Sep 2006 at 14:49

hardc0re_tid said:
i was told it will reduce the length of the battery

mine used to last over 1.5 hours, i used to use it on the mains all the time, battery wont even last 1 hour now!

i have an Acer 1350xc w/ standard battery

I think thats just the gradual death that all lithium ions go through, regardless of what you do to it. They all die of old age.

Corasik said:
Yep, 3 year life on LiIon is about right, and the chargers must shut down when the battery is full, or it will overheat, and explode.

Older NiMH batteries also need their chargers to shut down, as trickle charging an already full NiMH causes cell damage (Which some people put down to memory effect, but its actually heat damage from being overcharged). Deep discharge on a healthy NiMH is not advised, these cells dont like being discharged below 1 volt. If your battery is good, then its not ideal to deep discharge. On the other hand, if the battery is already 'bad' then it wouldnt hurt to try as a last resort, but dont try 'conditioning' a NiMH battery as 'preventative maintainance'.

The oldest NiCAD batteries do get memory effect, and should be fully discharged before every charge, but they can be trickle charged continuously once they are full. Its just bad to 'partially' use a NiCAD, and then put it back on charge before it was empty.

Lead Acid batteries should always be recharged, as the acids will eat away the battery if its not in a charged state.

All my chargers for both nicd and nimh trickle them perminantly, but at such a low level that they can dissipate it as heat with out it causing damage. I've never noticed my laptop battery getting hot when on mains after charging though so i expect it doesn't trickle it.

The nimh/nicd discussion isn't relevant to laptop batteries as they have been lithium ion for a very long time. I would much prefer a nimh laptop battery, as although the capacity might not be as high it woud last a lot longer.

You have to obey strict charge discharge cycles to keep nimh and nicd batteries in good shape, the ones i use for my rc car, which are packs of 6 sub cs, have to be charged fully and left on trickle for a time, as they are on a peak detect charger and the peak moves around a bit. Then after use they have to be discharged, and interestingly the dischargers made by the same companies that make the batteries all seem to cut off below 1v, some 0.8 and some as low as 0.6 so i imagine this is safe for performance batteries like these.

I am beginning to wonder actually, how do lithium ions compare with nimh these days in terms of capacity...? I bet they are pretty close if not better than lithium ions.