Today’s Question: My primary computer is a laptop, and so I tend to have it plugged in most of the time. I’ve heard that it is bad for the battery, but is this really a problem?
Tim’s Quick Answer: The issue with leaving your laptop plugged in most of the time is that the battery will never have a chance to discharge, which can cause the battery to degrade more quickly.
More Detail: Battery health is maintained longer when you allow the battery to go through regular discharge cycles. In the context of a laptop computer that means it is ideal to not leave the battery plugged in at all times, but rather to run on battery power and only plug the laptop in when the battery needs to be recharged.
This habit will help extend the life of your battery. If you leave the laptop plugged in most of the time, the battery health will gradually degrade, to the point that the battery won’t hold as much of a charge. For example, a healthy battery can be charged to 100%. An unhealthy battery might only have the equivalent of about a 50% charge, for example, even when you’ve completely charged it, and the battery shows that it is 100% charged. Eventually, a battery that is not healthy will get to the point that even when fully charged it doesn’t provide enough power to be useful.
I can tell you from personal experience that this battery health issue is very real. I have poor laptop battery habits, in that I keep my laptop plugged in most of the time. My wife has excellent habits in this regard, only plugging her laptop in when the battery level is low, and it needs to be recharged. On several occasions we have both gotten new laptops at the same time. After months of use, it starts to become very clear that the battery health on her laptop is considerably better than mine.
For Macintosh users, by the way, there is an easy way to check the current health of your laptop’s battery. In System Settings go to Battery, and click the info icon (the letter “I” in a circle) to the right of the Battery Health status. In the dialog that appears you’ll see an indication of your battery’s health, expressed as a percentage. This is the percentage of power the battery actually has when it shows as being fully charged.
Modern batteries perform considerably better in this regard than older batteries, but this battery health issue is still a factor and is worth considering when it comes to your habits about charging your laptop battery. And, of course, the same concept applies with other batteries, such as those for your camera.
