Most of us have at least one or two devices that run on rechargeable batteries, for example:
- cell phones
- laptop computers
- cordless phones
- Palm Pilots and other PDA devices
- iPods and other portable music players
- digital cameras
- electronic games and toys
- cordless power tools
- hair trimmers
- rechargeable flashlights
Most modern devices use Lithium-ion batteries (sometimes abbreviated Li-ion), so that type of battery is my focus, although most of my advice applies to other types as well.
Key things you should know about rechargeable batteries:
- They don't last forever. They are, in a sense, perishable.
- They don't fail suddenly. Instead, their ability to hold a charge diminishes over time.
- Don't buy a spare unless you need more run-time between charges than one battery can provide.
Under ideal conditions rechargeable batteries last 2-3 years. However, certain things can shorten their life quite a bit, leading to inconvenience and relatively expensive replacement:
- Constant charging (never permitted to discharge)
- Prolonged exposure to intense heat
- Improper storage when not in use
- Exposure to moisture
- Exposure to extreme (below-freezing) cold
Avoid Constant Charging: Exercise Your Battery to Avoid Atrophy
Many people (including me) don't want to run the risk of having a battery-powered device run out of juice when we need it the most. Unfortunately, always keeping your battery fully charged causes it to "atrophy" from lack of use. "Exercising" your battery is the solution! Take it out of the charger and let it run down to "low," then charge it up. Depending on the device, this may take hours or even days. Then, ideally every week or two, or at least every month or two, run the battery down to low and charge it up again. When it's fully charged again, take it out of the charger.
Your charger also makes a difference. Car chargers, while convenient, are more likely to charge too rapidly or over-charge than home chargers. Don't use your car charger as your only or primary charger.
Exercising Your Laptop Battery
Unlike most other devices, laptops can either run on A/C power or on battery power. In my experience, most regular users run on A/C power most of the time, rarely ever using the battery. If that's been your habit up till now, it's time to start exercising your laptop battery. Simply pick a time when you're going to be using your laptop for a few hours as you normally would, and then:
- Save any important documents you might be working on, just in case anything goes wrong.
- Pull out the power cord from your laptop. Your laptop should switch over to battery power.
- Continue working. In about 2 to 4 hours you'll see a "low-battery" warning. Or, keep an eye on the battery level and notice when it gets below 10%.
- Plug the power cord back into the laptop. Your battery will start charging again, whether you continue working, put it to sleep, or shut it down.
- Repeat this every week or two if possible, or at least every month or two.
You can monitor your laptop battery with the on-screen battery charge indicator:
- On most Windows XP laptops it's in the Taskbar at the bottom right of the screen; go to Control Panel->Power Options to make it visible and for other options.
- On most Macintosh OS X laptops it's in the Menu Bar at the top right of the screen; its options are in System Preferences->Energy Saver.
Avoid Prolonged Exposure to Intense Heat and Cold
When you park your car outside in the summer, the temperature inside your car can reach 150 degrees Fahrenheit or more. Leaving a battery-powered device in your extremely hot car for more than about 2 hours can not only permanently shorten the battery's life but also damage other parts of the device, including the LCD screen, the plastic case, and the glue holding it together.
Cold temperatures down to about 20 degrees for up to 2 days can temporarily affect a battery's ability to hold a charge, but it will usually recover once it warms up again. Even lower temperatures or longer durations can cause unrecoverable damage to the battery as well as other parts of the device.
Storing Rechargeable Batteries
If you're going to remove and store a rechargeable battery for more than a couple of weeks, don't put it away either fully charged or with a very low charge. Ideally, in order to have the least impact on its useful life, put it in an unsealed bag and store it in a cool, dry place like your refrigerator with a 40% (or medium) charge.
Storing Your Laptop Battery
If you tend to run your laptop on A/C power, the inside of your laptop can get quite warm, continuously exposing your battery to that heat. So, in addition to exercising your battery, consider also taking the battery out and storing it for a month or so to give it a rest; see "Storing Rechargeable Batteries" above. Don't forget to find a way to cover the laptop's empty battery cavity to keep dust and moisture out. Although it's not an elegant solution, I've used strips of clear packing tape for this purpose. On some laptops the battery also supplies the 4th foot, so removing the battery for storage might be awkward because it leaves you with a wobbly machine.
Avoid Exposure to Moisture
Dropping your device in water (or even exposing it to rain or a steamy, humid environment) can also damage your battery. If this happens, immediately pull it out of the water, remove the battery, dry it with a towel, and then let it air dry in a warm, dry place.
Summary
- Avoid constantly charging your rechargeable devices (cell phone, laptop, iPod, etc.).
- Exercise your batteries periodically or, if practical, remove them to give them a rest and store them properly.
- Charge at home more often than in your car.
- Don't leave them in your car, especially in the summer or winter.
- Keep your devices away from the pool, the tub, the sink, and out of the rain.
Where to go from here
- Notice what rechargeable devices you use and where you keep them.
- Learn how to find and read each device's battery level indicator.
- Learn where each device's battery is located and how (or whether) you can remove it.
- While you probably keep good track of your cell phone and laptop, check your car for any other less-used devices and find a better place to store them.
If you know someone else who might find this helpful, please feel free to forward it to them.
If you have any comments about this article, send me a reply!
If you have a topic that you'd like me to write about, I'd love to hear about it!
Many thanks to Chris Shea for his help with this article. Chris owns and operates the Batteries Plus store in Woburn, Mass., which is also a great place to bring old batteries of any type to be recycled for free. Learn more about his store at
http://www.batteriesplus.com/store_details/392.aspx or contact him at (781) 933-9093.
