The De-evolution of My Laptop Battery • Hacker News Board

Re: The De-evolution of My Laptop Battery

#31

Post by wikwocket » Fri, Aug 16, 2013, 6:45 PM UTC

Arjuna wrote: post #14

voidlogic wrote: post #7

>letting the battery cycle* Wait- I thought that was for NiCd batteries and Li-ion batteries where suppose to always be topped off? Furthermore going below 15-20% charge hurts their max charge level? *By cycle he means running it down and charging it up?

The official advice is: "Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her notebook 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…

I wonder if using your laptop plugged in at your desk 90% of the time, but carrying it around to use in meetings the other 10%, is as good as their "ideal use."

Re: The De-evolution of My Laptop Battery

#32

Post by untothebreach » Fri, Aug 16, 2013, 6:47 PM UTC

aeturnum wrote: post #16

YooLi wrote: post #4

If your cycle count is 223 and you are nearing 80%, then your battery is defective, plain and simple. Apple will replace it. It's happened to me a couple times and Apple took care of it with no hassles.

I had my first macbook's battery replaced. I took it into the apple store for an unrelated problem, the tech noted the awful battery life and asked me how old the laptop was, said, "that's not right...," and grabbed another battery. Nice and easy.

If I remember correctly, with the Macbook Air it will have to be '"that's not right...", and grabbed another Macbook Air, and started migrating my data, etc, etc...'

Re: The De-evolution of My Laptop Battery

#33

Post by rsynnott » Fri, Aug 16, 2013, 6:49 PM UTC

Axsuul wrote: post #11

My 2012 MacBook Air on a full charge only lasts 2-2.5 hours during an intense coding session. Am I the only one?

That seems abnormal, though possibly bad IDE behaviour? What is CPU usage like at this point?

Also, might be worth giving this a go: http://software.intel.com/en-us/articles/intel-power-gadget-...

Some badly behaved software (notably Netflix's Silverlight thing) will seemingly peg the CPU at maximum turbo-boost frequency for no good reason, which hits power usage hard.

Re: The De-evolution of My Laptop Battery

#34

Post by spartango » Fri, Aug 16, 2013, 6:52 PM UTC

glhaynes wrote: post #24

nakedrobot2 wrote: post #3

Wow, this is an excellent article! Nice visualization of the battery life. I am quite nervous about the battery sealed inside my own new Macbook. Is it better to attempt to use the battery as much as possible in order to get a new one before the 3 year Applecare Warranty expires? Or to maniacally keep the machine plugged in if at all possible? Or simply not to care? The price of a replacement will be high, and I wond…

I believe Apple charges $199 for a battery replacement, which is definitely not cheap, but might be worth it if you were still happy with the rest of the machine. I'm not sure how long it takes them to do it, though. I'd expect they'd continue to offer that service for quite a few years to come. As other posters have mentioned, it seems to me like the glued-in batteries don't rapidly decline like the old ones did. I…

Last time I did a battery replacement with Apple (for a mid-2009 Macbook Pro 5,5) it cost ~$120 off-warranty.

Doing the research, seems like different machines have different battery replacement costs from Apple:

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

* $129 for non-retina 11", 13", and 15" Macbooks (air and pro)

* $179 for the 17" Macbook pro

* $199 for the retina Macbook pros.

Re: The De-evolution of My Laptop Battery

#35

Post by glhaynes » Fri, Aug 16, 2013, 6:52 PM UTC

gz5 wrote: post #28

glhaynes wrote: post #24

Earlier quoted context omitted.

I believe Apple charges $199 for a battery replacement, which is definitely not cheap, but might be worth it if you were still happy with the rest of the machine. I'm not sure how long it takes them to do it, though. I'd expect they'd continue to offer that service for quite a few years to come. As other posters have mentioned, it seems to me like the glued-in batteries don't rapidly decline like the old ones did. I…

imo very conscious decision on part of Apple (and PC makers) to provide short battery half lives, rather than spending more money to deal with the size and heat/cooling constraints of laptops, especially the thin lightweight variety. not only saves them money short term, but helps push users to new versions before they really need to jump...

Is there evidence for this? Is there a better battery tech the entire industry should be using instead? Seems unlikely.

Re: The De-evolution of My Laptop Battery

#36

Post by outworlder » Fri, Aug 16, 2013, 6:53 PM UTC

As far as I understand, there are two major factors that will shorten the battery life considerably.

One is heat. This may not be avoidable depending on the computer usage. My mom "plays" Second Life (for english lessons) and her battery barely lasted two years - expanding to the point that the trackpad on her Macbook Pro was sticking out.

Another is leaving the computer plugged in all the time, which will top the battery - and apparently lithium batteries hate that.

Some electric cars have the option to only recharge the battery up to 80%, to increase the lifespan. Would it be possible to do the same with laptop batteries? Perhaps by patching the SMC?

Re: The De-evolution of My Laptop Battery

#37

Post by ddeck » Fri, Aug 16, 2013, 6:53 PM UTC

voidlogic wrote: post #7

>letting the battery cycle* Wait- I thought that was for NiCd batteries and Li-ion batteries where suppose to always be topped off? Furthermore going below 15-20% charge hurts their max charge level? *By cycle he means running it down and charging it up?

Assuming we're talking about lithium ion chemistry, The most significant thing that will impact the longevity of the battery is heat, and keeping the battery at a high level of charge generates it. In particular, if you're always plugged in and the charging system is keeping it at 100%, this will impact the longevity in a meaningful way.

Not sure about Macbooks, but my laptop has settings to control this. I typically have it setup to only start charging when the charge drops below 40% and to stop at 85%.

Some other points:

- It's preferable not to discharge fully. Very deep discharge can damage the battery, although all modern batteries have circuits to protect against this.

- For long term storage, ~40% charge is best. That's why new phones typically come charged at around this level.

Re: The De-evolution of My Laptop Battery

#38

Post by ddeck » Fri, Aug 16, 2013, 6:57 PM UTC

outworlder wrote: post #36

As far as I understand, there are two major factors that will shorten the battery life considerably. One is heat. This may not be avoidable depending on the computer usage. My mom "plays" Second Life (for english lessons) and her battery barely lasted two years - expanding to the point that the trackpad on her Macbook Pro was sticking out. Another is leaving the computer plugged in all the time, which will top the ba…

>Some electric cars have the option to only recharge the battery up to 80%, to increase the lifespan. Would it be possible to do the same with laptop batteries? Perhaps by patching the SMC?

My laptop (X1 carbon) does this, I assumed most did. The Lenovo power manager let's you choose when to start charging and when to stop. I start below 40% and stop at 85%.

Re: The De-evolution of My Laptop Battery

#39

Post by driverdan » Fri, Aug 16, 2013, 6:57 PM UTC

voidlogic wrote: post #7

>letting the battery cycle* Wait- I thought that was for NiCd batteries and Li-ion batteries where suppose to always be topped off? Furthermore going below 15-20% charge hurts their max charge level? *By cycle he means running it down and charging it up?

I've always kept my laptops plugged in whenever it's reasonable to do so and I get great life out of my batteries.

My 2008 T61 ThinkPad had 85-90% left when I sold it in 2010.

My 2010 15" MBP had nearly the same battery life after 2+ years as it did when it was new.

Here are the numbers from my current 2012 15" rMBP:

Age: 13 months

Cycles: 117

97% original capacity

And that's with 70+ hours a week of use.

Re: The De-evolution of My Laptop Battery

#40

Post by bjustin » Fri, Aug 16, 2013, 6:58 PM UTC

nakedrobot2 wrote: post #3

Wow, this is an excellent article! Nice visualization of the battery life. I am quite nervous about the battery sealed inside my own new Macbook. Is it better to attempt to use the battery as much as possible in order to get a new one before the 3 year Applecare Warranty expires? Or to maniacally keep the machine plugged in if at all possible? Or simply not to care? The price of a replacement will be high, and I wond…

The best approach is to not worry. The battery is supposed to retain 80% capacity after 1000 charges, which should still be enough for decent battery life. The $200[1] cost to replace the battery is well worth it for two years of moderate to heavy use without worrying about wear.

[1] Estimate, no idea if this is accurate