Why you should keep your phone battery above 30% (but below 80%)

Battery health has been in the news a bit the last few years, starting when people found out that Apple intentionally throttles (slows down) older phones in order to help with their battery performance. As a battery gets older, it can’t perform as well, and Apple chose to throttle old phones to help combat that. While Apple handled it poorly, the idea was solid and ultimately helps users. But why do batteries get worse over time, and what can be done to stop it?

Batteries are chemical

At their core, batteries perform chemical reactions in order to work. A side effect of those reactions is a bit of microscopic junk that accumulates in your battery, kind of like very small rock salt. The more that piles up, the worse the battery performance becomes, and there is nothing you can do to reverse it.

While you can’t reverse it, you can help prevent it. Generally speaking, with lithium-ion batteries (which is in virtually every device you own), going below 30% battery life is hard on a battery, as is filling it up to 100%. That’s right — keeping your phone charging overnight is slowly killing it. Of course, the trade-offs are likely worth it for most of us. You’ll lose a bit of battery life over the course of a few years, but you’ll have a full phone every morning and a new…