Am I damaging my battery by never using it?

I have a MacBook Pro that stays plugged in for weeks or months at a time. Am I damaging my battery by not using it? I know you should cycle it monthly to recalibrate it...is that good enough? Should I just take the batter out and shelve it for a while?

Thanks!

Solution 1:

Short answer: yes, this will damage your battery. Take it out for extended periods when it's not going to be used.

Lithium Ion batteries (as in your laptop) have a pretty short life anyway. Even if you leave it sitting on a shelf, never used, within 5 years or so it will be useless (which is why I feel sorry for people who are buying the $100,000 Telsa car, it's loaded with batteries that won't last for more than a few years!).

There's a great explanation of why this is on Wikipedia.

Solution 2:

Factors affecting Li-Ion battery life:

• Everything I've read says that Li-Ion batteries last longest if they're kept cool and lightly cycled: run them down a little bit and then charge them.

• They basically have a fixed number of discharge/charge cycles, so keeping them plugged in most of the time is fine. I see 300-500 cycles mentioned frequently, one site has it as high as 1000. Since Li-Ion's don't have memory effects, you don't need to "waste" cycles by running them down.

• Li-Ion batteries are sensitive to temperature, so if the computer runs hot, you're better off taking the battery out when the computer is plugged in. Anything else you can do to keep the batteries cool is a good idea.

• All batteries self-discharge, but Li-Ion's are slower than NiCads or NiMH's. So if you leave your batteries out for a long time, they'll need to be charged up again.

At one point, I tried to preserve my battery by taking it out when I was just sitting in the office w/ my laptop plugged in, but then I gave up and figured that for the life of my notebook, I could probably count on the batteries being available to buy a new one after a couple of years so I just use it and hope for the best.

Good sites for battery info:

Battery University: The Li-Ion Battery

Power Electronics article on Li-Ion battery care

Battery Education: How many times can I charge my battery

Solution 3:

Apple has a good webpage about batteries and an iCal calendar to remind you to regulary do a cycle.

Lithium-ion polymer batteries need to be used for maximum performance. If you don’t use your device often, be sure to complete a charge cycle at least once a month.

Solution 4:

Supposedly, the new MacBook Pros have "adaptive charging" that is tuned to each individual battery cell. This is designed to eliminate the headaches associated with maintaining lithium batteries that used older charging technology.

The technology is also supposed to extend the number of recharge cycles. It accomplishes this by tuning the charging and discharging of each individual cell.

See here for the marketing material on the subject.