It’s the murky aspect of gadget ownership: lithium batteries are fragile. They all gradually lose capacity, meaning it’s only a matter of time before your device isn’t carrying enough juice to be useful. But how long? Some of this is baked into the design – but the way we charge and use batteries can also make a difference.
For example, leaving your device plugged in most of the time can help you avoid the stress of being stuck with a low battery. But it might be stressing your battery.
So what can we do to make batteries last longer? I called two scientists who study lithium batteries, Gregory A. of the University of Michigan. Keolian and Michael G. of the University of Maryland. Pecht. “Temperature, state of charge and rate of charge are important drivers influencing degradation,” says Keolian.
He advised us to always follow the manufacturer’s specific advice. (For the record, here’s what Apple and Samsung have to say.)
But scientists have shared some useful general tips on how charging habits can help our batteries live longer, happier lives.
1) You don’t charge up to 20 percent
To squeeze the most life out of your lithium battery, your goal is to slow down the rate at which you burn through what are known as charge cycles. All devices are designed and manufactured by target number to completely discharge and recharge the battery. It is usually between 300 and 1,000.
So here’s a handy rule: don’t start charging until your battery reaches about 20 percent — and try to stop when you reach about 80 percent. This ensures that you maximize each cycle while keeping the battery stress-free. (Keep reading for details on how some smart devices like iPhones handle this for you.)
Is your battery blowing up like a balloon? Here’s the reason.
“It’s best to charge it before you go to use it — that’s ideal,” says Keolian.
It is true that the slower you charge, the less damage you will do to the battery. These days, some products are sold with “fast” charging capabilities when you use special bricks or car charging stations. Speed is obviously better when you’re in a hurry, but you should avoid it when you don’t need it, says Pecht.
2) Don’t plug it in at 100 percent — or let it go to zero
Many of us charge devices overnight while we sleep, which is fine. But then we plug them in to work all day or drive to the desk. “Avoid plugging things in 24/7,” Keolian says, because that can cause your battery’s capacity to fade.
The reverse is also true: being completely empty puts a strain on your battery, so avoid running your battery down to zero if you can.
And forget the myth that you must occasionally fully discharge and recharge to erase battery “memory”. This applies to lead-acid batteries, but not the lithium used by most mobile gadgets today.
Pecht recommends storing tools you don’t plan to use for a while, like an electric drill, at about a 50 percent charge. This means it’s not a good idea to leave things on their chargers when you’re not going to use them for a while. (We get laptops at the docking stations below.)
3) Do not overheat
Like most of us, our batteries are happiest at 72 degrees or cooler. And exposure to heat over 90 degrees in a car on a hot summer day is especially bad for battery chemistry. “Remember, when the battery is enclosed in a case, it can get even hotter,” says Pecht.
Cold temperatures (above freezing) are not bad, although some manufacturers advise against recharging in extreme cold. Pecht says he stores unused batteries in the fridge — making sure they’re not exposed to moisture that can destroy the electronics surrounding the battery.
4) Don’t worry too much about charging with the latest phone or laptop
A bit of good news: Over the past decade, products including high-end smartphones and laptops have gotten smarter at charging and automatically prevent some of the above mistakes.
Many laptops, which can sit in docking stations for weeks, are now known to stop charging and keep the battery below 100 percent — although Keolian says it’s still a good idea to unplug it every now and then.
Apple iPhones running iOS 13 or later have a nifty feature called Optimized Battery Charging that can track your normal routine and automatically give you a charging time to make sure it’s full before you wake up and start using it.
5) Don’t upgrade when the battery is dead — repair
If your device’s battery eventually goes kaput, you don’t need to get rid of it. Ask the manufacturer if there’s a way to replace the battery — or see if you can do it yourself with the help of a repair website like iFixit.
Getting a few more years out of an existing gadget will save you money, and it’s much better for the environment.
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