The care and feeding of li-ions

Lithium-ion batteries keep the “mobile” in work and play these days. But recharging is still a pain. Here’s a refresher, courtesy of Ars Technica, on what you can do to maximize battery life and keep recharge intervals to a minimum.

The techie web site recently updated its guidance on how to prolong the life of a lithium-ion battery, and the old rules they issued three years ago seem to have held up pretty well in the interim, with a few changes.

First, don’t run the device until it’s completely drained. Doing this repeatedly puts huge strain on the battery and reduces its useful life; the best thing is to do ‘shallow’ discharges, recharging the battery when it’s down to around 20 percent.

That said, devices like laptop clocks that estimate how much charge you have left can be confused by repeated shallow discharges. Manufacturers usually suggest you do a full discharge once a month (yes, run it right down to zero, just like we said not to) to let the device calibrate what a full discharge looks like.

Of course it’s a little more complicated, because li-ion batteries don’t like being fully charged either. The longer they’re fully charged – i.e. not being used – the more they suffer longer-term capacity loss. And writer Casey Johnston says that short, shallow discharges of a couple percent aren’t enough to keep the battery ‘in practice.’ You should let it run down more than that whenever you use it.

Also, li-ions are weather sensitive. Extreme cold affects them adversely, as well as extreme heat – either external or from the operation of the device, especially notebooks. Even running at room temperature for a year can cut capacity by as much as 20 percent. “Laptop batteries usually spend the most time in the worst possible state,” Johnston says, “plugged in at 100 percent charge, running at an elevated temperature.”

Got all that? That’s just the stuff Ars Technica told us three years ago that still applies. Now for what’s new.

Fortunately devices are getting better at regulating internal heat, partly thanks to flash storage. But temperatures can be more of a problem for smartphones, so keep them away from tight, badly ventilated spaces and heat sources. (Important reminder: the sun is a heat source.)

“But it’s also helpful to try and keep tabs on whether your phone is needlessly spinning its processing wheels, which is harder with some platforms than others,” Johnston says. “With Android, this is a little easier to suss out using the usage stats and process-manager interfaces. If something is idling and cranking up the temperature on your phone, kill it.”

iOS devides are harder to manage for this, but Johnston refers to a good overall device troubleshooting guide on that covers lots of ground.

Running the battery down quickly in shorter, high-energy bursts is a no-no, and probably worse for it than draining it slowly over a longer period of time.

Finally, wireless charging produces excessive heat, so it’s also contraindicated. However, considering the expense of a wireless charging setup, Johnston figures users in this category probably treat devices “like candy” anyway and likely don’t care all that much about maximizing battery efficiency.

At the end of the day, Johnston says, “the principle I first wrote stands: use your battery. Not too much. Mostly for small apps. Go forth and discharge. But gently. Ever so gently.”

Andrew Brooks
Andrew Brooks
Andrew Brooks is managing editor of IT World Canada. He has been a technology journalist and editor for 20 years, including stints at Technology in Government, Computing Canada and other publications.

Would you recommend this article?


Thanks for taking the time to let us know what you think of this article!
We'd love to hear your opinion about this or any other story you read in our publication.

Jim Love, Chief Content Officer, IT World Canada

Featured Download

ITW in your inbox

Our experienced team of journalists and bloggers bring you engaging in-depth interviews, videos and content targeted to IT professionals and line-of-business executives.

More Best of The Web