Keeping laptop plugged in vs cycle count

Question

I heard that it's bad to keep your battery fully charged all the time. It's best to keep it between 20% and 80%. On the other hand, cycle count degrades battery over time.

So, which of these is better if I want to maximize my battery longevity? 1. Only charge when battery is down to 20%. Stop charging when it reaches 80%. 2. Keep it fully charged all the time.

Answer 1

How to properly care for a modern rechargeable battery is a hot topic, possibly bordering on a religious war. How-To Geek has an article discussing many of the myths and facts about batteries, including several credible sources and their own tests. The TL;DR boils down to this:

• Charge cycles are often feared because manufacturers include number of cycles in their battery description. However, the batteries are not useless after this. They are just the expected number of cycles before the battery might experience a noticeable decrease in life.

• Draining a LIon battery to near 0% is not good for the battery, but it's hardly fatal either. Modern batteries will not overcharge at 100%. Batteries that will not be used for an extended period of time should be left half-charged for storage.

• Leaving your laptop plugged in all the time is not inherently bad for the battery due to the computer's smart charging abilities, and the batteries internal circuitry. What can damage them from this practice is excessive heating. If your laptop is not well ventilated or you know you'll be doing a lot of high-heat activities (gaming) you may want to remove the battery while it's plugged in.

To add my $0.02 of personal experience, my laptop is 6 years old and I leave it plugged in and running almost 24x7. Its battery lasted around 4 years before it became impractically short lived (<1 hour useful charge). The replacement battery is now 2 years old and still holding out well. I do keep it on a chill pad all the time, but I have not otherwise given any thought to caring for the battery. My biggest question is, What good is that 4-hour battery you've got if you're never going to use it for 4 hrs for fear that it won't hold 4 hrs anymore?

Answer 2

To my understanding, keeping a battery plugged in for very long periods of time, and also keeping it unplugged for very long periods of time (many months, or even years) can have a negative effect on the battery. Though normal wear of constant use should have a slight effect over a very long period of time (years most likely), I believe that the best way to save your battery and keep it from deteriorating is to let the charge run out a bit (i always go to 20%), and plug it back in (charging it to 100%), and let this cycle continue. This doesn't mean you have to do that 24/7, but it is good practice to do this while the device is in use. Also, to my understanding, using the battery while charging it can also have a negative effect in the long run. Also, for rechargeable camera batteries and the like, don't leave it untouched for months and years at a time. It is good practice to use or charge them at least once every 6 months (that's what I do).

Personally, my computer is a hand-me-down Windows Vista, and the battery hardly lasts more than a minute when its unplugged (plus countless other issues it has), so I have to keep it plugged in all the time. But for every other device I own, I use the methods described above.

Answer 3

Battery life doesn't depends on count cycle but it temperature dependant since high temperature may decrease the capacity concern and also keeping with low charge also affect the life since the battery would have some percentage of discharge rate.It would be better if you would Only charge when battery is down to 20%. Stop charging when it reaches 80%