Laptop Battery Maintenance and Optimization Laws: How To Get More From Lithium Ion Batteries

So let me get this straight, you’re telling me someone is now saying their iPod nano exploded? Okay, so the heat in my MacBook Pro can get pretty bad so I can see how a little chemical reaction going the wrong way, a drop of the old nano [that’s what they say] could set the heat on meltdown. But man, are we really basing our systems around little nuclear fuel cells that are nearing critical runaway on any given hot day?

To recap from an earlier post on battery maintenance:

  1. Short battery life in a laptop is mainly caused by heat rather than charge / discharge patterns.
  2. Consider taking out the battery if you are going to be on fixed power for an extended period of time. (your battery will receive and generate no heat, thereby saving some wear and tear on the molecules that make up the powering magic of the lithium ion.
  3. Avoid frequent full discharges because this puts additional strain on the battery.

laptop battery monitoring, battery capacityRecently in a ZDNet article the Apple Corps guys chronicled a story of taking in a MacBook when the Lithium Ion battery failed to hold a charge. What he saw was that the Apple Genius ran his battery through a software evaluation and determined that his battery “could” be replaced under warranty. The shocker was learning that there was a standard under which his battery would not have been replaced. And there were no published instructions from Apple on this standard. Not is his MacBook materials, not online, no where.

Here is what this Apple Genius says about their best-practices for battery life. [And if you don’t abide by these rules you might see your “paid-for” AppleCare warranty wind up useless if your battery tanks.] Remember these tips are NOT ON APPLE’S SITE. And why not Apple?

The chemistry inside a rechargeable battery works best when it’s used — translation: charged and discharged — and that if it’s always plugged into AC power (and fully topped off) most of the battery isn’t being used and will gradually decay. The genius helping me claimed to have 700+ charge cycles on his three-year-old battery and said that it still gets three plus hours of run time as as result.

So to complete this outline let’s go over some of the newly revealed information.

  1. The molecules inside your lithium ion battery want to be excited by being charged and discharged. But not too much. The recommendation is every 30 charges of so to let the battery run down to “low battery” status. There is no need to “fully discharge” the battery. In fact, discharging the battery too far puts it at risk for what is called Deep Sleep, from which the battery may not recover.
  2. Frequent use off-plug is a good idea. The little cycling is enough to keep most of your battery happy. But try and get to the “low battery” status at least once a month.
  3. Taking the battery out [only if you have a removable battery – doh!] while you are on plug is a good idea because the battery does not stay hot with the residual processing of the notebook. But taking the battery out is a pain, so…
  4. Keep the exhaust vents unobstructed. And adding a little tilt between the laptop and the desk may also help keep things cooler and the hotter air moving up and out of the machine.
  5. Beware that those cool leatherette covers can add to the heat of your machine. [I definitely notice about a 5 – 10 degree difference when I take my bright red cover off, but I like that it keeps my thighs from getting scorched by the aluminum frame of my MacBook Pro.]
  6. Keep your laptop out of the sun and out of hot cars. The ambient temperature can also affect the heat of the battery. If you have a desk fan you could even aim it to push air across the back of your laptop vents when you don’t need it yourself.

The part that really gets me is the heat of the overall machine. I don’t like the wrist-warming feature of my MacBook Pro. Perhaps on a really cold day it would be nice, but it feels too hot most of the time. [I wonder if it’s good for preventing carpal tunnel syndrome. I remember in the early days of the Powerbook I had one with 1/4 inch neoprene pads on the wrist rests. I’d like to have a couple of those now. They might look goofy, but when I’m writing a lot, the only way to get off the heating pads is to use an external keyboard.]

@jmacofearth
permalink: http://bit.ly/battery-optimization

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You will see from the chart below, it’s all about heat.

battery maintenance is about heat
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