Battery chargers vs. in-PowerBook charging

Battery chargers vs. in-PowerBook charging

Summary: There's a big difference between charging your battery in your PowerBook versus a dedicated charger.

TOPICS: Hardware

nwtcharger.jpgIf you're like me you probably charge your PowerBook's battery in the PowerBook itself and don't worry too much about it. While this is fine in most cases, it's going to deplete the charge capacity of your battery over time. Especially if you constantly unplug and re-plug your machine.

While it's true that Lithium-Ion batteries aren't susceptible to the "memory effect" of previous battery technologies (like NiMH, for example) a PowerBook battery only has a limited amount of charge cycles in its useful life. If you're constantly partial charging your 'Book, each of these counts toward your total cap of charges before the performance of your battery begins to drop off.

Apple has finally begun to acknowledge this fact on their dedicated batteries and notebook batteries pages, undoubtedly after some pressure from the iPod battery lawsuits. In a tiny sidebar called "Battery Lifespan" on the bottom right of their notebook batteries page they offer:

A properly maintained PowerBook or iBook battery is designed to retain up to 80% of its original capacity after 300 full charge and discharge cycles. You may choose to replace your battery when it no longer holds sufficient charge to meet your needs.

So if you un-plug and re-plug your PowerBook every day, say to take it back forth to work or school, you should have 80% of its original capacity after less than a year. And that's if you believe Apple's marketing spin on batteries—and we know how accurate they are on that topic.

I avoid this unnecessary battery abuse by running my PowerBook battery down to empty as often as possible and when a battery dies I charge it in my groovy external battery charger from NewerTech. The NuPower Battery Charger/Condition retails for US$149 and is worth every penny. It allows me to charge or condition two batteries at once quickly and correctly and its "deep conditioning" feature extends the life of my batteries.

If your old PowerBook battery isn't lasting more than two hours, you should first check it with a freeware application like Branden Keller's excellent Capacity Meter and if its capacity is less than 50% invest in a new high-capacity Lithium-Ion replacement battery from NuPower. You won't regret it.

Topic: Hardware

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  • GAACK!

    Shades of 1995! The Apple Newton owners were QUITE familiar with this battery hip-hop. The accessory holders/folders for Newton always had an extra pocket for that space battery pack. This silly practice was eliminated by the last Newtons and their long-lasting StrongARM processors. Just in time to be MURDERED! Has anyone asked why Apple is STILL not making a handheld? They could've cornered the market . . .
    Roger Ramjet
  • Misleading Interpretation of Apple Statement

    When they say the battery " designed to retain up to 80% of
    its original capacity after 300 full charge and discharge cycles,"
    that does NOT mean you're down to 80% as a result of using it
    every day for a year. A "full" charge/discharge doesn't happen if
    you use it a half hour in a coffee shop and then plug it in.

    I have a 3-yr-old PB that I run on battery almost every workday
    on bart, approx once weekly on an airplane, and at various times
    around the house in the evenings. Yes, I have gone thru one
    battery but the second is still going strong -- still good enuf for
    a DVD in the air if I'm careful about power use (brightness, CPU
    speed, etc.)

    I don't see how the charger really pays back its cost to possibly
    extend a $129 battery's life, at the cost of having to watch the
    battery level much more closely, keep a spare battery handy, and
    carry a bulky object when traveling for more than a couple of
    days, all to go into a 'book that won't likely be a portable for
    more than 5 years. Care to amplify on its value?
  • No! DON'T deep-discharge Li batteries often!

    and check as well

    Nickel-based batteries (particularly NiCd) should be deep-
    discharged every time...Lithium-based batteries should not! Once
    every 30 or so charges. I can see uses for an external battery
    charger, but daily deep-discharging is _not_ one of them.
  • Not exactly or even approximately true

    A lithium-ion battery that is rated for 300 full discharge cycles is also rated for thousands of shallow discharge cycles. A rule of thumb in battery design is that the life of the battery is related to the total number of electrons drawn from it, therefore 300 full discharge cycles is equivalent to 600 half discharge cycles, or 3000 1/10 discharge cycles.

    As with all rules of thumb the relationship is only approximate.

    For more information see the blog at

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