Hey, I recently bought a 15 inch Macbook pro (yes, excited since it replaced my 7 year old Pentium 3 desktop), and I am wondering what the proper way is to allow my battery to last as long as possible in the LONG RUN (in terms of changing the battery and it losing its capacity). For much of the time, I have access to a/c outlet, so should I just leave the it plugged in as much as possible? Or should I only plug it in when the battery is used up and take it out when the battery is full again? Thanks.
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Battery Long-Term Advice?
- Thread starter chronicfuture11
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Always keeping it plugged in is bad. As it just sits there, it discharges and then when it gets to 90% or so, it gets charged. This is very bad for the battery. Always running it down is bad, as the battery can only handle so many charge cycles.
montycat
macrumors 6502
killerrobot
macrumors 68020
Keeping it plugged in long term is just fine. It won't hurt it and it will actually keep the cycle count lower and prolong the life of the battery.
It's the large battery drains that really put a dent on the cycle count, not the tiny trickle effect that occurs when it's plugged in.
You still need to remember to drain it fully and calibrate it every one or two months though.
It's the large battery drains that really put a dent on the cycle count, not the tiny trickle effect that occurs when it's plugged in.
You still need to remember to drain it fully and calibrate it every one or two months though.
This is not accurate at all. The battery will discharge just sitting there and the computer will charge it. Lithium Ion still suffers from the memory effect. Not to the degree that NiCad and Ni-MH did, but it is still there.
So repeated cycles of just a 5 to 10% charge will hurt the battery in the long term. Batteries will die mainly to one of two factors; age or charge cycle count.
From Apple:
I would go more often than once per month. Try once per week. Considering 52 weeks per year, the battery will die from age and not cycle count.
killerrobot
macrumors 68020
Think about what you're saying. Yes, cycles do build up eventually with 5-10% charging, but not nearly as fast as a 100% cycle every day. Therefore, keeping it plugged in and trickling will prolong the cycle count and the battery life.
As I stated before, you still need to calibrate every one or two months. More than that for light battery usage is being paranoid and again will increase cycle count. (Every calibration creates a full charge and discharge.)
EDIT: I didn't heed your advice and my battery is nearly three years old and working excellently. This is the same thing I've done with four laptops I've owned. I've never had to replace a single battery.
I know two people that didn't heed my advice and left their machines plugged in. Both had to buy a new batteries after about two years. If they unplug the machine, one gets about 10 to 15 minutes, the other gets 0 minutes.
Where did I say everyday? I said once per week and even then, it will die from age, not cycle count.
The 17" Apple has said 1,000 charge counts. So even using everyday and full discharging it would equal to almost three years.
miles01110
macrumors Core
If you've got AC access most of the time, what's the issue? Just leave it plugged in.
By the way, anyone who cites Apple's "It's important to keep the electrons moving" website deserves a painful death. What does that even mean? Electrons never sit still in the first place. Either explain why it's important using real terms or stop reciting stupid corporate advertising.
By the way, anyone who cites Apple's "It's important to keep the electrons moving" website deserves a painful death. What does that even mean? Electrons never sit still in the first place. Either explain why it's important using real terms or stop reciting stupid corporate advertising.
I already have, try reading.
Why do YOU think it will cause no harm? Either explain it or quit spreading FUD.
miles01110
macrumors Core
Let's see...
Wow, I feel so enlightened. Did you copy this from Simplepedia, or did you write the article yourself?
A little better, but you've still yet to explain why it's good to "keep the electrons moving." Memory effect- great. What causes it? Do you even know, or are you just googling and using terms you can't explain?
Experimental evidence.
2006 Macbook Pro, battery #1:
Battery age = ~3 years (original), 36 cycles, 91% health
2006 Macbook Pro, battery #2:
Age: ~2 years, 41 cycles, 95% health
2006 Macbook Pro, battery #3:
Age: ~2 years, 10 cycles, 98% health
2006 Macbook (roommate's)
Age: ~3 years, 510 cycles, 76% health
2008 Macbook:
Age: ~1 year, 5 cycles, 100% health
2009 Macbook Pro
Age: 2 months, 20 cycles, 100% health
Shrug. As far as covering the entire spectrum of use/non-use, there's no evidence that suggests leaving your laptop on AC with the battery in is bad.
Miles, are you saying that it's good to drain 5%-10% of battery life daily and then keep it plugged in? (<--This applies as long as you drain battery once a week and you calibrate monthly?)
miles01110
macrumors Core
I'm not saying it's "good"- I have no idea if it's "good" or not. I'm saying that based on my experience it's not going to have a noticeable effect on your battery life.
Based on my experience, it hasn't been good for my battery.
2 years old, 88 cycles, 16% health.
Well, I keep my laptop on all day, and I have the in-built battery, so I can't remove it. Should I drain down to 20% everyday then as a practice?