With the MacBook and Macbook Pro models, Apple has switched from Lithium-Ion batteries to Lithium-Polymer batteries. The Lithium-Polymer battery, like Lithium-Ion, will slowly lose charge capacity over time until it gets to a certain point. When it reaches that point, its lifespan is up and it will just go completely dead. Replacements are currently over $100. In order to have that battery last as long as possible, follow these eight guidelines as best as you can.
Lithium-Ion battery technology does not last forever. As anyone who has had a laptop for more than a few years can tell you, there gets to be a point around 2-3 years when the battery really just doesn’t seem to be what it used to. You can vaguely remember it lasting for hours and hours when you first bought your laptop, now it barely can get through the first half of a movie. For MacBook and MacBook Pro owners, this can be a bigger problem. When the Lithium-Polymer battery’s time has come, it will just stop working. The trade-off is that the Lithium-Polymer seems to retain a higher charge capacity until the end. Don’t panic or think that there’s anything wrong. Believe it or not, this is normal.
First, lets discuss the Lithium-Ion/Lithium-Polymer battery cycle. Each time you discharge and recharge the battery, it remembers this as a cycle (or part of a cycle if it did not completely discharge and recharge). This is cumulative, as discharging the battery to say 75% and then recharging does not count as a complete cycle. As time goes by, the amount of charge the battery can hold will shrink. According to Apple, at 300 full charge/discharge cycles your battery should be able to hold 80% of its original capacity if it was properly maintained. (For older, Lithium-Ion models)
While the Lithium-Polymer batteries do exhibit the same loss of charge capacity, albeit slower, they are of the same overall technology and can benefit from the following guidelines to keep them alive as long as possible.
Eight suggestions to make sure that your battery is cared for and has a long life.
Keep the battery cool
The worst enemy of Lithium-Ion/Polymer battery life is heat. The battery is extremely heat sensitive with repeat exposure to heat drastically reducing battery life. Therefore avoid leaving your laptop in a heated car, keep the battery out of sunlight and be mindful of the outside temperature. If its a hot and sunny summer day, don’t bring the laptop to the beach. This also includes heat generated by the computer itself. If you are pushing the processor hard, use the laptop on AC power and remove the battery. My old iBook G4 can get pretty toasty when I push its processor as can a fully stressed MacBookPro.
Calibrate the battery every few months
Unlike older rechargable battery technology, the Lithium-Ion/Polymer batteries do not suffer from memory issues. So you can partially discharge them and then recharge them often. The batteries in your laptop, however, have a gauge in them to tell you how much power they have left. After time, these gauges can get out of sync with the battery and must be recalibrated. It is recommended that about once every few months you fully charge the battery and then run the laptop on battery power until the low power warning comes up. Then plug the laptop in and fully charge it.
For the official Apple recommended way, visit this link.
Avoid full discharges unless calibrating
Frequently draining the battery all the way or nearly all the way will put additional strain on the battery. With older NiMH battery technology this was common “must do” because of memory problems with the battery remembering where it was recharged from, reducing its capacity. Now, with a Lithium-Ion/Polymer battery, this isn’t the case. Its better for the battery to be partially discharged and recharged again than giving it a full discharge and bringing it back.
Use the battery every now and then
A laptop that just sits on AC power all day and never on the battery will reduce how long it lasts. Give it some exercise by unplugging every now and then – Apple recommends giving it at least one charge cycle a month. So, unplug for a bit at least once a week and it should add up to one charge cycle a month. Remember, partial discharges are better than full. For those who do primarily use AC power, read on.
Remove the battery from the casing when using primarily on AC power
When running off AC power mainly, as in your laptop stays plugged in almost all of the time, take the battery out and store it. The constant charging of the battery is not healthy for it as is not exercising it.
A laptop running off AC usually runs hotter as its power management features allow the processor to run at full strength. Heat is the number one enemy of lithium ion battery life. While researching this article, every single place I went to and found recommended that you remove your laptop battery when using on AC power for the constant charging aspect, the not usage aspect as well as the heat aspect.
Note: As of August 2008, this tip is no longer recommended for the latest MacBooks and MacBook Pros as they will automatically slow down their processing speed without the battery connected. For more information, here’s the support article.
Store when removed by keeping in the fridge at around 40% charge
Proper storage of a lithium ion battery is critical to its long lifespan. You want to avoid heat as well as have it stored in a stable condition. It is recommended to store the battery in the refrigerator to keep it cool and to have it stored at 40% of its charge to ensure a stable condition. If you use the laptop primarily on AC power, store the battery in this way to keep it as healthy as possible.
When purchasing a replacement battery make note of its age – do not buy old batteries.
As nice as having a spare battery is, if you don’t use it – it ages. If you need a spare battery, store it properly. If you just want to have one just in case the other one goes bad, you are better off waiting until the other one goes bad. After 3 years, even with proper storage, that spare battery won’t be as good as a new battery. When buying batteries, don’t buy an old battery. Batteries begin aging the moment they are manufactured so be sure to inspect those clearance batteries.
Keep an eye on your battery’s health with Coconut Battery
A great little utility that gives you battery health information is CoconutBattery from Coconut-Flavour. It shows cycle-count, current maximum charge, original maximum charge, approximate computer age, and current battery status.
So, how long does it take for your laptop to reach 300 cycle counts? Depends on your usage. Personally, I use my iBook mostly on AC power, however at least once or twice a day it is running off battery while my wife uses the computer or if the power strip that it charges from is off. I’ve had this current battery for at least a year and a half, maybe a few months longer and I’m currently at a cycle count of 133. Not bad, I’d say its pretty normal usage – by 300 cycle counts, the battery should be approximately 3 years old.
If you are curious about your own battery usage, download CoconutBattery and look at the statistics. If you’re a more advanced OS X user and want more details, look for your battery information in System Profiler (10.4 and up). Its under the Power tab.