Does allowing the Battery to drain to 0% depletes full charge capacity?

Question

I bought a Macbook pro 17-in intel core 2 duo 2.4Ghz from the Phiippines on July 10, 2007 and brought it to Ireland couple of days after. Later, I upgraded to leopard 10.5.2 with 4 Gig memory. Auto updates have been installed since its first use. The only problem I encountered (except for some Safari quitting unexpedtedly) was in the battery.
Here is the record of my MBP battery use:
Battery information
Battery : MBP 17in Rechargeable Battery
Model: A1189 10.18V 68Wh
Serial: 6 _ _ _ _ _ DVYF1A
My Battery practice:
- I wait for 5% remaining charge before I plug the charger
- At several occasions I forgot to plug the charger before remaining charge goes to 0%
- I usually unplug the wall charger as soon as full charge is indicated.
- I sometimes leave the wall charger plugged for several hours after green light shows.
- I use my MBP for an average of 12 - 14 hours a day. At times I dont shut it down and just allow it to go to sleep mode.
- Calibrated about 10 times.
Record of Battery Life/Charging
Battery Cycle Life (based on istatpro) Full Charge Capacity (based on MBP)
1 100% No Record
62 100% 6492 mAh
66 100% 6484 mAh
100 100% 6484 mAh
300 98% 6213 mAh
301-317 95-99% 5850 - 6109 mAh
318 83% 5254 mAh
318 (at 3908mAh or 53% remaining charge MBP suddenly shuts down)
318 (MBP shuts down if wall charger is unplugged) Tried calibrating and resetting SMC but did not work.
I then checked if my MBP is still covered by the one-year warranty despite more than 300 battery cycles, no bulges present at apple website https://selfsolve.apple.com/GetWarranty.do (here you have to enter your MBP serial number)
I brought my MBP for check up here in Dublin, Ireland and indeed the problem was the battery. They replaced my battery with a new one without cost.
Thanks Apple my new battery now has a Battery Health of 100% with the following initial cycle records:
Battery Cycle Full Charge Capacity
1 (33% remaining charge as soon as I received it) 6810 mAh
1 (I then used the remaining charge up to 1%) 6726 mAh
1 (full charged) 6810 mAh
1 (full charged) I let it rest for few hours then checked 6879 mAh
2 (full charged) 6879 mAh
3 (full charged) 6876 mAh
4 (full charged) 6830 mAh
5 (full charged) 6845 mAh
5 (full charged) I let it rest for 1 hour then checked 6868 mAh
6 (3% remaining charge) 6829 mAh
I forgot to plug the charger (battery drained to 0%) 6492 mAh
Notice the sudden drop of full charge capacity in cycle 6? How do I recover the lost charge capacity? Does letting the battery drain to 0% depletes its full charge capacity?

Answer 1

The short answer is that yes, completely draining the battery has a slight negative impact on full charge capacity. The full charge capacity does fluctuate a bit over time, but the general trend is downward no matter what you do - there's a continuous chemical reaction occurring in the battery, with a finite life.
However, I note that you state +I wait for 5% remaining charge before I plug the charger+; if you are doing this because that is what you need to do, i.e. you do most of your work away from a power source, fine. But, if you are doing that because you believe that's best for your battery, that is incorrect. The 'old' NiCd batteries performed best with full discharge and full charge. The 'newer' Li-based batteries do not have this requirement, and in fact perform better over time when used frequently but 'lightly', avoiding full discharges (except for the occasional battery calibration, which allows the OS to more accurately determine the time to charge and discharge).
More details can be found here:
http://www.apple.com/batteries
http://www.apple.com/batteries/notebooks.html
http://www.batteryuniversity.com/
Hope this helps...