About the MBP battery

[danipower0204]

Hi guys. I have a mid-2009 unibody MBP. I have searched for the best ways to keep the battery top notch, but I have a question. Is what matters with the battery the charge cycles? Because if so, would it be better to leave the laptop plugged in when at home, so it doesn't use up charge cycles, or should I plug it out once charged fully? I have been charging it up and then running off the battery once full, and I'm on 10 cycles, and according to Battery Health Monitor and coconut battery I have 95% of capacity remaining.
What would you advise?
Thanks,
Dan

 

[sammich]

Leave it plugged in whenever possible. That's pretty much it. Yeah cycles = usage and wear. That's why if you're not using the battery, it will last longer.

 

[gr8tfly]

These two links are Apple's take on battery health and maintenance. Basically, leave it plugged in and use it once a month or so. That's about it.

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

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

 

[electroshock]

Leave it plugged in whenever possible. That's pretty much it. Yeah cycles = usage and wear. That's why if you're not using the battery, it will last longer.

If you leave it plugged in on AC power all the time, you'll find that when you do actually use the battery, it generally will last for a shorter time than a regularly conditioned/exercised battery. Batteries were meant to be regularly used.

Apple, in their infinite wisdom at http://www.apple.com/batteries/notebooks.html says:

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.

Basically, it's a tradeoff between fewer cycles but ending up with shorter runtimes or having more cycles but also getting longer runtimes and a more accurate battery meter. I know which approach is more important to me.

In normal charge/discharge use, the number of cycles aren't a big deal in actual practice. Apple generally expects at least 300 cycles and 70% charge before a battery needs to be replaced. Many people never reach 300 partly because of their computing habits such as leaving it on AC power 24x7 for months on end. (And it's possible to last beyond 300 cycles; 300 is just a minimum threshold.)

I like to use the coconutBattery app to help with the discharge/recharge process.

 

[gr8tfly]

If you leave it plugged in on AC power all the time, you'll find that when you do actually use the battery, it generally will last for a shorter time than a regularly conditioned/exercised battery. Batteries were meant to be regularly used.

Apple, in their infinite wisdom at http://www.apple.com/batteries/notebooks.html says:

Originally Posted by Apple, Inc.
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.

Which goes on to say there's an iCal reminder set to remind you to use the battery once a month.

To add to the cycle info: "The built-in battery in the new 13-, 15-, and 17-inch MacBook Pro is designed to retain up to 80% of its original capacity at up to 1000 full charge and discharge cycles."

 

[danipower0204]

Thanks for the replies. I doubt it will hold 80% at 1000 charges. It's already at 95% after 10

 

[electroshock]

Thanks for the replies. I doubt it will hold 80% at 1000 charges. It's already at 95% after 10

Well, the discharge curve isn't linear. So as long as it's regularly conditioned, it should do well over time.

 

[gr8tfly]

Thanks for the replies. I doubt it will hold 80% at 1000 charges. It's already at 95% after 10

Meant to say cycles. For what it's worth, here's my data: I have 9 cycles and according to this data, I'm at 98.3% remaining vs. full capacity.

Charge Information:
Charge remaining (mAh): 12486
Fully charged: Yes
Charging: No
Full charge capacity (mAh): 12708
Health Information:
Cycle count: 9
Condition: Normal

I forgot to ask if you have followed the full calibration cycle. Charge full and leave at that state for 2 hrs minimum; unplug and run off battery until auto-sleep; leave unplugged for 5 hrs; then, fully charge (it can be used during the charge). Please double check me on the procedure - I'm doing it from hazy 3:05AM memory.

Here's one more link where they define what a cycle is (for their purposes): http://www.apple.com/batteries/ Charge Cycle. Using and recharging 100% of battery capacity equals one full charge cycle.

 

[danipower0204]

I kind of did it, but instead of fully charging it the first time, I drained it (started at 70%) completely till sleep, let sleep for 5+ hours, then fuly charged it and left it plugged in for around 1.5 hours. I did this cause the guy at the store told me to first drain it.

 

[iphone3gss]

I have a mid-2009 15'' also. In coconutBattery it shows Age 3 months, Battery-Loadcycles: 129, Current Battery Capacity: 6227 mAh, Original Battery Capacity: 6500 mAh (95%). I charge to full and then run off the battery throughout the day. I've found actually using the battery helps a lot. The battery in my 13'' that is a year old has 400+ cycles and is still 95%.

 

[cameronfield]

2 month old 13" MBP
31 Cycles
90%



Is that bad? I still get 4-5 hours on it in class using wifi/word!

I think the problem I use I dont let it run all the way down (or at least to 10%) when using it on battery...should I start doing that?

 

[gr8tfly]

2 month old 13" MBP
31 Cycles
90%



Is that bad? I still get 4-5 hours on it in class using wifi/word!

I think the problem I use I dont let it run all the way down (or at least to 10%) when using it on battery...should I start doing that?

No, it's not necessary to fully cycle the battery - there's no memory effect as NiCads used to have. You can just use it as you like.