Maximizing long-term battery life

[FredT]

I've heard many different views on what you should do to care for your battery, so I'm looking for some more information.

I have a MacBook and my strategy is to keep it plugged in as much as possible to avoid using charge cycles. If I use it down to 50%, then get home, I'll plug it in so I've only used half a cycle. Then when I'm just using it around the house, I try to keep it plugged in.

My friend has a completely different strategy. At the Apple Store, one of the salesmen told him that he should use it down to almost nothing and then charge it back up again. He would never plug it in at 50%, but wait until it is 10% or less. He gave me this analogy: if you have a bottle of milk in the refrigerator and you have a cow outside, you refill the bottle when it is empty. If you keep refilling the bottle when it is only half empty, that milk is going to go bad. He really doesn't understand how it works himself, but said something about the battery's memory? I never imagined that a battery would have its own little memory or something, but now that he mentioned it, it does seem reasonable.

Really, what is the correct battery "etiquette"?

Thanks!

 

[VSMacOne]

The way you do it is correct, and 100% recommended by Apple..

http://support.apple.com/kb/HT1490

Just make sure it doesn't stay plugged in ALL THE TIME, and that you calibrate it about once a month..

Standard Maintenance
For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her MacBook Pro on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month. Need a reminder? Add an event to your desktop’s iCal.

http://www.apple.com/batteries/notebooks.html

 

[OptyCT]

Battery memory only applies to nickel-based batteries (in cordless drills, for example) and not lithium ones, like the one in your laptop. As a result, there is no benefit to fully discharging your lithium battery before recharging it. That being said, you should fully discharge your lithium battery from time to time. This is a good practice for optimal battery maintenance. The biggest threat to a battery is heat. However, since the majority of us are cognizant of heat and its effect on CPU's, GPU's, RAM, etc., I don't think this really becomes an issue when using a laptop.

 

[shady825]

The memory your friend is referring to applies on nickel-based batteries.
A good example would be say a cell phone. If you continually charge the battery when there is 50% power left, over time the battery will start thinking that it is empty once it reaches 50%.
(If I'm wrong, this is just the way it was explained to me awhile back)

My $0.02

The way you are charging your battery sounds fine to me.

 

[bozz2006]

this is nit-picky... but most new cell phones have lithium ion batteries, too.

@OP - I don't think there's necessarily anything wrong with your method, but letting it go to 50% and then charging it is not recognized as half of a charge cycle. If you plug it in, and it takes a charge, that is a charge cycle. your battery isn't going to just quit working when it reaches a certain number of charge cycles. rather, charge cycles, in my opinion, are a lot like miles on a car. some cars go for many hundreds of thousands of miles. some die at one hundred thousand. it depends on how well you take care of it. just like everything else, YMMV.

 

[VSMacOne]

this is nit-picky... but most new cell phones have lithium ion batteries, too.

@OP - I don't think there's necessarily anything wrong with your method, but letting it go to 50% and then charging it is not recognized as half of a charge cycle. If you plug it in, and it takes a charge, that is a charge cycle. your battery isn't going to just quit working when it reaches a certain number of charge cycles. rather, charge cycles, in my opinion, are a lot like miles on a car. some cars go for many hundreds of thousands of miles. some die at one hundred thousand. it depends on how well you take care of it. just like everything else, YMMV.

A charge cycle means the battery has been discharged and charged a total of 100%. Try istalling iStat or even coconutBattery and unplug your MB, let it go down to 60% (or whatever) and then charge to 100%. It will not record a CYCLE until you have reached a total of 100% in discharge/charge.

Also, batteries ARE guaranteed for a certain number of cycles.

Beyond that, I agree that what affects the life of the battery is HOW you use it, and I think the links form my last post explain that very well.

 

[jackiecanev2]

Wirelessly posted (iPhone: Mozilla/5.0 (iPhone; U; CPU iPhone OS 2_2 like Mac OS X; en-us) AppleWebKit/525.18.1 (KHTML, like Gecko) Version/3.1.1 Mobile/5G77 Safari/525.20)

this is nit-picky... but most new cell phones have lithium ion batteries, too.

@OP - I don't think there's necessarily anything wrong with your method, but letting it go to 50% and then charging it is not recognized as half of a charge cycle. If you plug it in, and it takes a charge, that is a charge cycle. your battery isn't going to just quit working when it reaches a certain number of charge cycles. rather, charge cycles, in my opinion, are a lot like miles on a car. some cars go for many hundreds of thousands of miles. some die at one hundred thousand. it depends on how well you take care of it. just like everything else, YMMV.

Incorrect; charge cycles are cumulative. That is, any portion of a charge is that portion of a cycle: depleting the battery to 50% and charging, then depleting to 50% and charging is one complete charge cycle.

 

[hari-bhari]

complete drain. complete fill. almost every single day for 363 days. ended up with 102% battery capacity right before i sold it. nuff said

 

[w00t951]

That's quite amazing... I know from 5 laptops of experience that it is recommended to drain your battery a little bit at least twice a week. It is also highly recommended against to fully discharge your battery frequently, unlike Nickel Cadium or Nickel Metal Hydrate. Source: http://www.apple.com/batteries/notebooks.html

 

[sml238]

That's quite amazing... I know from 5 laptops of experience that it is recommended to drain your battery a little bit at least twice a week. It is also highly recommended against to fully discharge your battery frequently, unlike Nickel Cadium or Nickel Metal Hydrate. Source: http://www.apple.com/batteries/notebooks.html

where does it say that it's bad to fully discharge the battery? it only says it's bad to keep it plugged in.

 

[whiteking]

Laptop battery comes with memory is inevitable. But lithium ion battery is a little memory. The only thing you can do is to reduce the number of charge cycles. So you must try your best to extend the time of a single charge. Turn off some functions or program if you don't need them.