Questions

1. What’s the average lifespan of a rechargeable battery? Do batteries get worse over time?

Answer:
Li-ion batteries (like the one in your phone) generally have a lifespan of 300-500 cycles. What is a cycle? Well, anytime your phone is charged to 100% and fully discharged down to zero, you’ve gone through one cycle. Now that doesn’t mean your battery will last forever if it never hits 0%. The effect is cumulative. If you use your phone until the battery is down to 20%, charge it to 100%, and then run it down to 80%, you’ve gone through one cycle. Luckily, 300-500 cycles will still last a long time. Even with super-heavy use.

As for whether or not Li-ion batteries get worse—they definitely do. Battery University 34 tested several Li-ion brands and, sadly, the data shows they start deteriorating pretty quickly.

2. Do high or low temperatures impact battery life?

Answer:
Batteries can operate over a wide range of temperatures, but extreme temperatures definitely affect battery life. Charging is much more delicate than discharging, so charging in extreme temperatures surely won’t do your battery any good. Li-ion batteries are particularly sensitive to heat and will deteriorate more rapidly if they reach temperatures above 80℉ (which almost certainly happens to yours when you charge your phone). The main impact of heat on Li-ion is faster degradation. Capacity is more rapidly reduced, meaning your battery holds less power.

All batteries are negatively impacted by the cold but Li-ion batteries offer reasonable performance at cooler temperatures and charge optimally in a range of 41°F to 113°F (5°C to 45°C). The current should be reduced for temperatures below 41°F and charging in below freezing environments can permanently damage your battery.

 

Now That's Cleared Up

We’ve all learned a little more about batteries.
BUT, what about the things everyone advises us to do? Are they true?

 

Common Battery "Knowledge"

What you’ve heard: “Using your phone while charging will damage the battery.”

I think we’ve all had someone advise us not to use our phones when they are charging because it will overtax the battery. Maybe that was true a long time ago, in a bygone era of charging. Battery technology has advanced since then so this isn’t really a concern anymore, unless you’re using a low-quality charger (the antithesis of Anker chargers). Really though, if you’re not turning off your phone while it charges, you’re using it anyway (syncing data). Casual use while charging shouldn’t have a massive impact on battery life.
 

What you’ve heard: “You should charge a new phone to 100% before using it.”

Many people are positive that the first thing they should do with a new smartphone is plug it in and charge it to 100%. This myth originates with nickel batteries (like the ones you use in power tools), of which this is true. However, Li-ion batteries work best when charged between 40% to 80%. Since most phones ship at half capacity, you should be good to go out of the box.
 

What you’ve heard: “Unplugging and using your phone before it’s finished charging will negatively impact battery life.”

Untrue. Actually the opposite is better for Li-ion batteries. Like we said before, Li-ion batteries operate best between 40%-80%. Furthermore, continuously charging for an extended period can strain your battery. Ideally, you should recharge your battery every time you run it down by 10%.
 

What you’ve heard: “Charging your phone past capacity will damage the battery.”

Phones today are smarter than you think. Most come equipped with a protection circuit to keep the battery from overcharging. But, they usually keep the current trickling to make sure that the battery stays topped off so you shouldn’t necessarily charge your phone all night, every night.

You wouldn’t keep filling up a cup with water if it was already full, would you? Keeping your battery in the magic 40-80% zone that we keep mentioning has a positive impact on battery longevity.
 

What you’ve heard: “You should periodically charge to 100% and run down to 0% to maintain your phone’s battery.”

This is completely, and utterly false when it comes to Li-ion batteries. Going from extreme to extreme can actually wear down the battery faster. That 40%-80% zone really is where you want your battery to be. We keep bringing it up for a reason.