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Laptop - battery or mains power?


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#1 Technique

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Posted 12 January 2013 - 21:12

I'm a new laptop user & just wondered how you guys powered your laptops. Obviously if you're on the move then you're going to rely on battery power, but if you have the option, which do you lump for?

I would imagine mains power to be better as the more you use the battery the more it'll deteriorate. I don't know how long the better batteries last for, but my dad had a cheap Acer laptop & the battery was gone after a few years & he wasn't a hardcore laptop user.


#2 Detection

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Posted 12 January 2013 - 21:17

My advice is not to even think about it, it just drives some people crazy

Laptop batteries will last a good 1.5- 2 years+ no matter what you do, apart from extreme use obviously

Just use it how and when you like, and put a few $£ aside for the next year or 2 for a new battery

I see so many people obsessing over battery use instead of enjoying it, when you feel its not holding a charge as long, start saving... simples ;)

#3 TurboShrimp

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Posted 12 January 2013 - 21:23

laptops are so cheap these days I buy a new laptop every year or two anyway never had a batt go bad on me

#4 Crisp

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Posted 12 January 2013 - 21:32

My laptop is left plugged in 24/7 and the battery still has a minimum of 2 hours life. I've had this laptop going on 3 years now.

#5 TokiToki

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Posted 12 January 2013 - 21:44

Just use it however you feel like, but if you're going to leave it plugged in 24/7, be sure to discharge/charge it once every 2 weeks or so. Leaving it plugged in 24/7 for extreme periods of time will shorten its life.

#6 medhunter

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Posted 12 January 2013 - 22:25

What is your laptop model?HP?

#7 Nayos

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Posted 12 January 2013 - 22:34

As long as it says plugged in, not charging in the system tray, you're fine

#8 OP Technique

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Posted 13 January 2013 - 21:16

Laptop is a Lenovo L530

24/7? I've nothing to gain from doing that.

Also, new laptop every so many years? They may be cheaper than they used to be, but i don't have money to burn. I've other things to be spending money on - such as a house.

#9 xendrome

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Posted 13 January 2013 - 21:20

Use your AC power when you have it and battery when you need it.

Your system will change profiles also when it is on battery so it is going to run slower, a new battery could be bought for $50 in a couple of years when you need it replaced.

#10 xendrome

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Posted 13 January 2013 - 21:27

Just use it however you feel like, but if you're going to leave it plugged in 24/7, be sure to discharge/charge it once every 2 weeks or so. Leaving it plugged in 24/7 for extreme periods of time will shorten its life.


Not with a lithium ion battery, that is a good way to actually kill the life of the battery.

#11 primexx

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Posted 13 January 2013 - 22:48

there's a lot of battery myth around. for lithium ion/poly batteries in computers/phones/etc. there are three major factors affecting battery wear, only one of which you can really make a big difference in.

1. temperature: you obviously don't want the battery to be too hot or extremely cold. since the battery sits so close to the rest of the components which all generate heat, that arrangement isn't exactly ideal. however, there's not much you can do about it. you can't run the computer without power so you kind of need the battery to be in its slot. you can take it out and run only on AC when you're near an outlet, but there's a convenience/reliability trade-off in that if the AC is unplugged you lose power immediately. Considering that in well designed systems most of the time the temperatures won't exceed the battery's safe range, this isn't really worth the effort to save a tiny amount of battery wear.

2. charge level: ideal storage charge is ~40% full capacity. at either extreme (0% or 100%) it stresses the cells and wears them down more quickly. from anecdotal observation the near 0% end is a lot more damaging than the near 100% end. you can't really do much to optimize this either since it's not really practical to run around with a half-charged machine, although some manufactures do give you an option to artificially cap the maximum amount to charge your battery in order to lower wear (e.g. only charge to 80% to avoid the stresses of a full charge). that's dependent on the machine you have and battery time you require. in general, try to charge up your computer at around 20% and don't let it fall below 5-10% unless absolutely necessary. not much else you can do about this.

3. charge cycle: these batteries are usually rated to between 300-500 cycles (newer ones seem to be 300 cycles more often). each cycle is one full charge and discharge. so say if you only used 50% and charged it back to full, that counts as half a cycle. this is critical to your decision of whether to keep it topped up. since there's no memory like old alkaline batteries, the only concern is how you can minimize the number of cycles. so let's examine several scenarios.

3a. same usage pattern as "memoried" batteries (i.e. charge it up, use it down, charge it back up...): this is the worst result you can get. you're constantly charging and discharging the battery unnecessarily, using up precious cycles and repeatedly hitting the stresses of the high and low charges.

3b. manually keeping the capacity at ~40% charge: sounds good, except by manually doing it, what you're really doing is just continuously charging/discharging the computer by a couple of percentages each time at a higher frequency, since when you unplug the AC you're actually using the battery. this gives you basically the same cycle-count as 3a. not to mention the hassel of constantly plugging/unplugging and monitoring the percentage.

3c. have an application do it for you: this is much better. when the battery hits a designated percentage you don't switch to running on battery power, but simply stop charging until the natural discharge (loses some charge very slowly even when nothing's using it, happes to all batteries) reaches some level. gives you the same cycle-count as holding it at full but without the stress. con: you're only at around half-capacity when you need use it unexpectedly, and I don't know of any battery utility that actually lets you do this.

3d. run on AC with the battery pulled out at ~40%: this is even better for the battery, you avoid the heat too. but like I said above on temperature, the benefits don't really justify the convenience and reliability of having your battery in.

3e. keeping it at full charge at all times: this seems pretty bad on the face of it because you're constantly holding the battery at a stressed level at full charge. however, that's really the only downside. you have a fully charged battery ready to go. it gives you some flexibility, and you're not constantly charging and discharging it so you're not using cycles like crazy - at full charge it cuts off automatically, and since you're not actively using the battery, the natural discharge takes a while before capacity drops enough to engage a top-up charge, so it's not really constantly doing it. these top-up charges are eating into your cycle count but they're small enough that it takes a lot of them to eat away one cycle. it's not going to be a concern for most people at the rate with which these things are replaced with newer and shiner stuff. yea the 100% stress is bad, but it's far worse to keep using up precious cycles.

so looking at the options, keeping it plugged in whenever you conveniently could strikes the best balance between convenience and battery-preservation for the vast majority of use cases despite all the tips online about not keeping it at full charge all the time, because the alternatives either involve a lot more work on your part, or in fact wears down the battery quicker.

#12 Aergan

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Posted 13 January 2013 - 23:16

If you're on Windows, pay attention to various power saving plans and options specific to the hardware & technologies in your device. The smarter you use your battery, the longer you can go between full charge cycles.

I have a "balanced" configuration which when on battery, gives me ample enough horsepower to play the odd game of killing orcs with traps or watch a good few episodes of Fringe. Usually I get up to 3-4hrs depending on what I am doing.

When I know I will be away from a power source, I have a power saving plan that I use for just web browsing, RDP or scripting/coding can last 7hrs+.

Bluetooth devices are a good way to save on power compared to a traditional USB or proprietary wireless device.