Comments on: Conditioning Your Battery

By: SamChevre

SamChevre — Mon, 08 Oct 2007 13:48:53 +0000

OK. I know something about batteries, but nothing about mac batteries.

The reason there is so much contradictory advice out there is that different batteries are different. Lead-acid batteries (car batteries) do best if they are kept charged—full cycling is bad for them. Some of the dry batteries need to fully cycle, some don’t.

By: joejoejoe

joejoejoe — Sun, 07 Oct 2007 21:30:25 +0000

For what it’s worth, I used to drive a fairly expensive electric forklift made by Toyota and the Toyota rep (and manual) said to run down the batteries completely and then recharge. We used to get in trouble from the maintenace department for doing otherwise. As someone said above—I belive the chemistry of the battery makes a difference. I know this is an apples-to-oranges comparison but it’s charging routines are not just urban legend with laptops.

By: joel hanes

joel hanes — Sun, 07 Oct 2007 02:40:16 +0000

Dan Rutter provides a definitive answer to the question of battery conditioning, with attitude.

By: Mike D.

Mike D. — Sun, 07 Oct 2007 02:34:04 +0000

I tend to run my battery all the way down, and charge it all the way up, out of superstition if nothing else. From experience, I do know that if you leave it in “sleep” mode for a week it will discharge your battery to a point where you will need a replacement. Turn off the computer on vacation, and all should be fine!

By: mapantsula

mapantsula — Sat, 06 Oct 2007 23:07:02 +0000

Nu … After 32 months my 17” PowerBook is at 68% After 24 months, my wife’s 12” iBook is at 92%.

By: nu

nu — Sat, 06 Oct 2007 20:40:47 +0000

question: i have 57% capacity after 21 months of use.
I probably have to say that my laptop was extensively used in 4 different countries including 2 with VERY unreliable power (surges, blackouts).
So is the loss normal or should i be worried about my mantainance habits ?

By: Tom S.

Tom S. — Sat, 06 Oct 2007 16:34:04 +0000

As said before, don’t worry about conditioning, Nickel Metal Hydride and Nickel Cadmium batteries needed conditioning.

By: M. Gemmill

M. Gemmill — Sat, 06 Oct 2007 13:40:59 +0000

What ever you do, rest assured that you will almost certainly need to purchase at least one new battery within the useful lifespan of the computer. My PB is going on three years old, and my second battery is starting to lose its ability to hold a charge. I’m hoping to replace the computer around Christmas time, so it would be nice if it would stay useful until then.

You can check the battery’s capacity with a free utility called Coconut Battery (find it on Versiontracker). It tells me that my current battery charges to about 60% of its proper capacity, which is consistent with my experience of how long the computer lasts before running out of juice.

By: Aaron Swartz

Aaron Swartz — Sat, 06 Oct 2007 13:26:58 +0000

This may conflict with all the previous advice, but here's a fairly clear algorithm which, while not guaranteed to give you the right answer, will at least give you a definitive one: Do what Apple says. http://www.apple.com/batteries/

By: abb1

abb1 — Sat, 06 Oct 2007 13:25:57 +0000

http://en.wikipedia.org/wiki/Lithium_ion_battery

By: Jacob Rus

Jacob Rus — Sat, 06 Oct 2007 11:35:53 +0000

There's a great article about lithium ion batteries that was linked at some point from MacOSXHints.

By: Jacob Rus

Jacob Rus — Sat, 06 Oct 2007 11:33:13 +0000

Fully discharging your battery and recharging it once is recommended by Apple, because it calibrates the battery meter. This has nothing to do with “conditioning” your battery, and will hurt battery life if done repeatedly (do this once, and then again whenever you notice the meter is not giving accurate percentage readings).

As for conditioning, you should in general not worry about how much you discharge the battery. Feel free to plug it in at whatever charge, and unplug it again as needed (e.g. to take the laptop outside) whether it’s full or not. One thing to keep in mind is that it is (slightly) bad for the battery to run it all the way to 0. Doing this too much will shorten its lifespan. If you can plug it in when it’s at 10% or something, that’s generally a good idea.

If you plan to store the battery for long periods of time, and not use it, then leaving it at ~40 percent charge will best extend its life.