Keep Your Battery Healthy


One of the things people tend to ask about very often is some variation on a theme of “When I’m doing X with my laptop/iPod/phone, should I do Y?” This post is basically going to be a bit of a compilation of the usual worries and some of the facts behind common misgivings about battery life and what kind of impact battery life on battery life different activities might have.

You’ll have to forgive the number of times I refer to “notebooks” as “laptops.” It’s a force of habit thing, but I’ve tried to correct it as much as possible.

Discharging Your Battery:

Something we tend to hear people advised to do a lot when they’re experiencing issues with their lithium-ion batteries is to “fully discharge” the battery and then plug it back in and give it as long as it needs to get back to a full charge. This is some fairly sound advice, but because of the way it’s usually worded it can often lead to people going to great lengths to “fully discharge” their batteries.

notebook batteries

To cut a long story short, you’ll never really want to let your battery get below about 5% of its total capacity. As a rule, most devices won’t allow you to dip below that minimum level of charge. Most devices and their batteries will work in tandem to make absolutely sure that you can’t dip below the minimum allowable battery remaining. Indeed, if you’re running a MacBook with a removable battery (the white models still have them) then you may already know that allowing a battery to run down completely can result in a dead battery, refusing charge entirely from that point on.

Still, despite all the protection, you’d be surprised just how often people manage to find a way to get rid of that last little drop of charge. A complete discharge like that is often referred to as a “deep discharge,” and it’s one of those things it’s really in your best interests to avoid.

In the simplest terms possible, that last bit of charge is what a battery needs to keep track of its own total capacity, among other bits and pieces. If you manage to bleed it dry then you’ll be removing its ability to track its own capacity properly. Depending on your battery that can result in an immediate dip in your total capacity by up to twenty or thirty percent or (as in the above case) the battery being rendered totally useless.

In short, you’re far better off not putting a load of effort into totally discharging your battery, no matter who says it’s a good idea 😉


Of course, there are exceptions to every rule and there are times when you’ll find your battery just plain needs calibration or recalibration. This isn’t anything like as painful and tedious a process some make it out to be, but it will take some time and effort.

Notebook battery 1

Fundamentally, calibrating a battery is a relatively simple task; you run the battery right down to it’s bottom five-ish percent of its total charge and then you fully charge it. This is likely the source of the advice that people often dispense about it being better for a battery to completely run it down.

Cycles, Not Time:

Another thing that not nearly enough people are aware of is that battery life can usually be measured more accurately in terms of the number of charge cycles it’s undergone in its lifetime than the amount of time the battery has actually been in use. When people talk about a battery’s total charge being diminished by about half over the course of a year or so, that doesn’t actually tell us too much about the battery itself. Often, a much more relevant measurement would be the number of charge cycles it took to reach that point.

In general terms, a single charge cycle is a total discharge, from a full charge right down to the five or so percent that represents the minimum charge your battery will let itself fall to and then being charged to 100% again,

Another issue we often hear is that, “If a battery is only good for X number of charge cycles, should I only plug in my machine when the battery has completely run down?” While that makes a certain amount of sense, you shouldn’t worry about it. This is something that gets misreported all the time, but in lab tests from reliable sources it’s been pointed out that, if you plug in at fifty percent charge and let it charge up the rest of the way, then you’re only up ½ a charge cycle. Basically, we wouldn’t worry about plugging in your machine just because you’re already part-way charged.

The idea of battery “memory” retained from previous charges is an idea that’s just kind of become part of our collective consciousness though, so you’ll see plenty of battery-life recommendation lists pointing out that you should never plug in a machine unless the battery has been fully discharged first. It’s a pretty resilient idea, but it’s not something to be too concerned about.


There’s been an awful lot of talk recently about whether or not you should keep your battery in your notebook while you’re plugged in and working away, as long as you’re not charging it. In some ways, that’s true, though not for the reasons you might think.

There are all kinds of reasons to be careful with batteries...

There are all kinds of reasons to be careful with batteries...

The fact is that lithium-ion batteries aren’t damaged nearly as much by the effects of trickle charging while they’re plugged in and don’t need a charge as they are by the heat a plugged in machine tends to generate. The ideal state for a lithium-ion battery really would be for it to be charged and somewhere not too much above (or at all below) zero degrees Celsius. Anything above that isn’t fantastic for it, but room temperature’s not as detrimental as you might imagine.

One of the biggest problems will be for those who tend to play games or do heavy duty media work on their notebooks, then you’re looking at parts of the laptop hitting the high sixties Celsius, which is pretty bad for your battery indeed. There aren’t too many figures around for just how much of a negative impact that might have on your battery, but any easily avoidable negative impact should probably be avoided.

By the same token, if you have to store a spare battery it’s often said that the ideal state to store a spare battery in is charged, sitting in a cold, dry space. If you feel like it, there’s no reason not to wrap it up in plastic and seal it in the fridge until you find yourself in need of it.

Father Time:

Of course, there is a certain amount of ageing that effects batteries independent of whether or not they’re being used. Even a charged, inactive battery stored in an ideal space (cool and dry) will see a degradation of a few percent of its total capacity every year. Sadly there’s no real way to avoid that, it’s something we just have to live with.

Batteries get old, they just do it a bit faster than people do.


Well, that’s about it for this post folks. Hopefully this relatively quick read has taught you at least a couple of things about keeping your battery operating at maximum capacity for as long as possible, but beyond what’s been said above there’s just one last tip we can give for those of you in the market for new laptop batteries.

If you’re buying a new battery then the single best thing you can do for yourself is not buy one when you’re buying your notebook, if only because you’ll be the proud owner of two batteries, aging at roughly the same rate (if only due to time) regardless of which you’re using more. For most, it’s a better bet to hold off on picking up extra batteries for as long as possible, if only to ensure the longest life possible. That said, there area always going to be people who just plain need two batteries for one reason or another, so that’s advice that won’t suit all equally. Use your judgement 🙂


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