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View Full Version : someone told this about laptop batteries



cptrohn
November 21st, 2010, 01:47 AM
That if you are not using the battery just remove it when you are running off AC power because it can damage the battery? Is this true? I have never heard this before, (and have a new 12 cell battery on the way for my laptop..)

BigCityCat
November 21st, 2010, 01:52 AM
Li Ion batteries have life cycles. Meaning every charge and discharge is a cycle. When the battery is in it is always charging. When the pc is off it discharges. Turn the computer back on and it charges again. This burns through cycles and reduces the life of the battery. Mine lays on the floor most of the time.

73ckn797
November 21st, 2010, 01:55 AM
If you are running on AC power with the battery removed, be prepared to lose data if the power supply accidentally disconnects.

wirepuller134
November 21st, 2010, 01:57 AM
We use Lenovo laptops, and have them all set to not charge the battery unless it falls below 80% to avoid this.

jdong
November 21st, 2010, 02:00 AM
Lithium batteries are sensitive to heat, so if your laptops are constantly powered on and running on AC power, the amount of heat generated nearby the battery could negatively impact its lifespan.

CharlesA
November 21st, 2010, 02:19 AM
I haven't really noticed any major reduction in battery life on my netbook from leaving the battery in all the time. I'm usually running it off AC power too.

cptrohn
November 21st, 2010, 02:25 AM
Thats very interesting to hear..... So if this is the case is there a way or an option in Ubuntu to disable the charging in Ubuntu unless you actually want the battery to charge?

Ric_NYC
November 21st, 2010, 02:37 AM
I've heard of it. I think it makes sense.

czr114
November 21st, 2010, 03:14 AM
That if you are not using the battery just remove it when you are running off AC power because it can damage the battery? Is this true? I have never heard this before, (and have a new 12 cell battery on the way for my laptop..)

That might have been true of old laptops with lousy charge controllers.

If the laptop is on AC, it shouldn't be in a constant charge/discharge cycle.

My latest HP has been run almost entirely off of AC for the past 3 years. I've noticed no appreciable degradation in battery life. My Compaq from roughly a year before that was frequently subjected to a charge then deep discharge cycle, and the battery's life was appreciably cut short.

lisati
November 21st, 2010, 03:18 AM
My previous laptop (one of the Toshiba A100 range) was run off mains most of the time, and the battery didn't last too well. By the time I gave it to my nephew, the battery would only last about 5 minutes. My current laptop (also from Toshiba) seems to have a longer battery life. Something has changed but I haven't bothered looking into it much.

3rdalbum
November 21st, 2010, 04:24 AM
Urban myth. It's obvious that this myth comes from the days of primitive batteries and primitive charge controllers, where it was possible to overcharge a battery and damage it.

These days, your computer CANNOT overcharge a battery.

handy
November 21st, 2010, 09:51 AM
...
These days, your computer CANNOT overcharge a battery.

That is true, but certain types of batteries (Li-Ion) do have a limited number of charging cycles before they expire.

NightwishFan
November 21st, 2010, 11:14 AM
I think this link should be relevant for any brand that uses these types of batteries. http://www.apple.com/batteries/notebooks.html

3rdalbum
November 21st, 2010, 11:25 AM
That is true, but certain types of batteries (Li-Ion) do have a limited number of charging cycles before they expire.

How many charging cycles? 1,000? After three years being used every day your laptop's hard disk would be dying, and the computer would be obsolete, so the replaceable battery is the least of your worries.

aysiu
November 21st, 2010, 11:48 AM
Based on these two links, I'd say it's true:
http://batteryuniversity.com/learn/article/how_to_prolong_lithium_based_batteries
http://www.apple.com/batteries/notebooks.html

Don't leave your laptop plugged in all the time if you're trying to maximize your battery life.

NightwishFan
November 21st, 2010, 11:51 AM
I am going to leave my battery in. I think by the time mine dies, I can buy a new one. If one is not available, I will probably be using some form of netbook for portable stuff by then anyway.

Sean Moran
November 21st, 2010, 12:29 PM
Much the same as mobile phone batteries isn't it? When you first take your new pride'n'joy home, get her setup nice, on AC power, and then take some time to run down the battery 100% so that she develops a memory of what a battery is meant to do.

I always thought that my Presario CQ60 would have another CMOS battery that keeps the clock ticking when I'm asleep and she's shutdown. I don't believe that the big fat laptop battery gets discharged one iota when I shutdown for the night. Tell me I'm wrong.

CharlesA
November 21st, 2010, 01:03 PM
I always thought that my Presario CQ60 would have another CMOS battery that keeps the clock ticking when I'm asleep and she's shutdown. I don't believe that the big fat laptop battery gets discharged one iota when I shutdown for the night. Tell me I'm wrong.

I can only speak from my experiences with my netbook, but if I have the battery hooked up and not in use (netbook is off and not hooked up to AC), it loses the charge. I don't know if that's cuz it's keeping time or what, but I know it's consistent.

MarcusW
November 21st, 2010, 01:11 PM
From the apple link:
"If you store a battery when itís fully discharged, it could fall into a deep discharge state, which renders it incapable of holding any charge. Conversely, if you store it fully charged for an extended period of time, the battery may experience some loss of battery capacity, meaning it will have a shorter life"

I think that kinda happened to a friend of mine. (storing a battery discharged) He was really careful with always removing his battery when it wasn't needed, so it would last longer. A couple of months later he had 12min battery time.

stefangr1
November 21st, 2010, 01:12 PM
My previous laptop (one of the Toshiba A100 range) was run off mains most of the time, and the battery didn't last too well. By the time I gave it to my nephew, the battery would only last about 5 minutes. My current laptop (also from Toshiba) seems to have a longer battery life. Something has changed but I haven't bothered looking into it much.

Back when XP came out I had a laptop that already after a few years couldn't do more than 5 minutes. One year later there wouldn't be time enough to go from one power plug to another when changing seats (if that would take more than a few seconds)...

I think it's all about the microcontroller that does the power management. I assume that if it's optimal to not draw any power from the battery when it's fully charged, the controller takes care of this.



I think that kinda happened to a friend of mine. (storing a battery discharged) He was really careful with always removing his battery when it wasn't needed, so it would last longer. A couple of months later he had 12min battery time.

I've read that its better to "keep the electrons flowing" with Li-Ion batteries. Even though the number of cycles is an important indication for battery life, I don't think you can extent battery life by keeping a laptop on the grid all the time (or taking them out, for that matter).

Now that we're talking about batties: does anyone know how bad it is to interrupt charging? I sometimes do this for a few minutes, when I change to another room. Or if I have little time I may charge it only half.

And recharging when the batteries are not empty: does that still make batteries "lazy"?

Sean Moran
November 21st, 2010, 01:52 PM
I can only speak from my experiences with my netbook, but if I have the battery hooked up and not in use (netbook is off and not hooked up to AC), it loses the charge. I don't know if that's cuz it's keeping time or what, but I know it's consistent.
Thanks Charles. I only go off my memopry of desktop computers, and the little coin-shaped batteries that run thew CMOS on the motherboards when we shutdown, and that my Ubuntu Karmic has a laptop battery indicator to show when it is charging or discharging, and I have never seen it try to charge before when I boot up in the mornings, but maybe she just likes to keep some of her early-morning things to herself. So do I, so I won't complain about my laptop's morning habits.

handy
November 21st, 2010, 02:06 PM
How many charging cycles? 1,000? After three years being used every day your laptop's hard disk would be dying, and the computer would be obsolete, so the replaceable battery is the least of your worries.

I don't want to buy notebook batteries. Hard drives are cheap & easy to replace. Obsolescence is in the mind of the beholder. We have a nearly 10 year old Powerbook here that has done an enormous amount of work, & it is still going strong, though its battery has been useless for a long time.

From the Apple site:

And thanks to advanced battery chemistry and adaptive charging technology, the MacBook battery can be recharged up to 1000 times ó good for about five years of typical use ó and lasts nearly three times the lifespan of typical notebook batteries.

I don't want to buy notebook batteries.

CharlesA
November 21st, 2010, 02:20 PM
Heh, I'd rather just run it on AC power then have to buy a new battery, the damn things are expensive.

73ckn797
November 21st, 2010, 02:27 PM
I have had several rechargeable batteries that would no longer take a charge that I wrapped up and left in a draw for 10 years. On a chance I plugged it into a charger and they took a charge and are working normally. These were batteries for cordless drills. I have not tried this with any laptop batteries.

handy
November 21st, 2010, 02:32 PM
Heh, I'd rather just run it on AC power then have to buy a new battery, the damn things are expensive.

Obviously that's what we do.

Not only expensive, but due there being so many devices that use them, the resources are diminishing to the point where China wants to mine for some of them in ocean!

http://bluelivingideas.com/topics/marine-ocean-sea-life/china-plans-deep-sea-mining-copper-nickel-cobalt-silver-gold-international-waters/

CharlesA
November 21st, 2010, 02:35 PM
Obviously that's what we do.

Not only expensive, but due there being so many devices that use them, the resources are diminishing to the point where China wants to mine for some of them in ocean!

http://bluelivingideas.com/topics/marine-ocean-sea-life/china-plans-deep-sea-mining-copper-nickel-cobalt-silver-gold-international-waters/
D'oh!

I really wish we'd all move onto renewable sources of fuel/power production/storage.

stefangr1
November 21st, 2010, 03:23 PM
D'oh!

I really wish we'd all move onto renewable sources of fuel/power production/storage.

I'd like to propose a small nuclear fuel cell, such that you'd never need an external energy source.:popcorn:

3rdalbum
November 21st, 2010, 03:29 PM
I think we need the Mythbusters to bust some myths about batteries. You can pretty much charge Li-ion batteries as you please without hurting them. The "storing batteries while flat damages them" is probably true, although it's actually the recharging after the deep discharging that damages the batteries.

The "memory effect" doesn't actually exist. It's a myth. Some people observed that, if they partly discharged their AA cells and then put them into a "dumb" recharger that works from a timer, then the cells would appear to lose capacity. However it wasn't a "memory effect", it was that the cells would get overcharged and start venting electrolyte. If you recharged the cells by the amount that they had been discharged, you wouldn't get a problem.

Modern batteries that you find in CE are usually controlled by smart charging circuits, not dumb timers. Thus, no overcharging.

madjr
November 21st, 2010, 03:37 PM
if you have 2 batteries, exchange them every week and let the other one rest.

jdong
November 21st, 2010, 06:38 PM
Again, the charge controller prevents overcharging, but the problem with running a laptop all the time with AC power is the heat! I've seen some pretty frightening laptop designs that place the battery pretty close to either the power supply or the CPU/GPU, and those batteries are being subjected to temperatures well over 70 degrees C whenever the laptop's on. That's going to kill you battery.

eotakos
November 22nd, 2010, 01:05 AM
ok - I was concerned with this thing also, and then a couple of years ago I bought a sony vaio laptop. I was surprised to see that there is a special feature to preserve the battery life.

So, there is a software/driver that limits the maximum percentage of charge that the battery reaches when is connected to AC. Therefore what you can do, is set it to "super-saver" where the battery charges only up to 50% and it is a choice targeted for situations when you are constantly connected to AC power. If you are about to use the laptop as it should be used :-) aka portably, you can remove the limit and let it charge fully.

Of course, this comes with a price... you need windows to use this feature. well, you need windows to set the limit. If you want to cancel the limit, you just disconnect the battery and then connect it again. So... I dual boot. There! I said it :-) (well, that's one of the two reasons and the most important - the other one is gaming)


But... with my old laptop I did take off the battery when I didn't need it. I was still connected behind a ups though... and as far as I'm concerned it worked. The battery still performs nicely after 2 complete cycles (charge-discharge)

handy
November 22nd, 2010, 02:07 AM
I think we need the Mythbusters to bust some myths about batteries. You can pretty much charge Li-ion batteries as you please without hurting them. The "storing batteries while flat damages them" is probably true, although it's actually the recharging after the deep discharging that damages the batteries.

Li-ion batteries don't like heat either, it is recommended that they are stored in the fridge when not in use. Though depending on climate that they live in that may not be necessary.



The "memory effect" doesn't actually exist. It's a myth.

Depends on the type of battery you are talking about. It certainly does exist with Ni-Cd batteries.