Guide to Smartphone Battery Technology

If you’re like most people, then you probably don’t think about your smartphone battery much until it starts to die — or explode, for Galaxy 7 owners. However, there’s actually a lot of interesting and nuanced information on these power cells that could be useful to know.

Read on to learn more about these lithium-ion blocks that fuel our TikTok goals!

The Basics of Smartphone Batteries

When talking about smartphone batteries, you can assume that in 99% of situations, it’s going to be a lithium-ion cell. While NiCad and NiMH batteries may have been the standard of the day, they have fallen out of favor in the contemporary phone market.

Smartphone battery technology

Furthermore, lithium polymer batteries haven’t really caught on with manufacturers — save for Samsung who used it in the flagship Galaxy S20 — due to the higher production cost. This is despite their benefits over lithium-ion batteries and ubiquity in the RC hobby niche.

In essence, smartphone batteries rely on chemical reactions to transfer electrons from one side of the power cell to the other, then back again when discharging. For a more in-depth answer on how batteries work, see our full guide on that.

Charging Etiquette

The question on what the best charging habits are to maximize the lifespan of your battery is one that comes around time and time again. Even as we’ve gone through multiple generations of smartphones, ventured into foldables, and advanced our tech, battery health is still a concern.

While it’s not practical to obsessively control what percentage your smartphone sits at, the general rule of thumb is that you shouldn’t fully charge the battery nor should you allow it to drain completely as either state puts undue stress on the anode.

Over time, letting your battery deplete to 0% or filling it up to 100% can cause the formation of dendrites which affects both the capacity and lifespan of your lithium-ion cell. Keeping your phone charged between the 30%-80% range will reduce the voltage the battery has to deal with.

This, in turn, extends its lifespan.

Ultimately, batteries are going to degrade over time regardless of what you do albeit at a slower pace if you’re diligent in your regimen. That being the case, it’s probably better to just get a battery replacement every few years for under $100 than constantly worry about charge level.

Two-Phase Fast Charging

You’re probably wondering then, “If higher voltages put battery health at risk, then what’s with all the 30W Warp Charge and Dash Charge offerings from newer phones?” While manufacturers would love it if you replace your phone more often, fast chargers aren’t their idea of sabotage.

In reality, companies like OnePlus have found a clever way of getting around the voltage issue, pushing more amperage into your phone during the first phase of charing then slowing down when you get closer to a full charge.

This gets you the “70% charge in 30 minutes” performance that every phone owner wants without putting the health of the battery in jeopardy. However, it would seem as though Pete Lau isn’t done there.

The OnePlus 8T is going to feature 65W charging. To accomplish this, they’re going to put two batteries into the phone. By splitting the capacity, they’re making it possible for their chargers to run at full speed for longer before having to throttle down around the 70% mark.

Slowing Drain Speed

Of course, you don’t need to have fast charging just to keep your phone percentages above 30%. Another method, one far more popular in those with older phones, is to slow down the rate at which your battery drains.

There are quite a few methods that you can use to do this. First off, you’ll want to reduce the brightness on your screen. While OnePlus may brag that their 8 Pro can output over 1,400 nits, you don’t need to max it out unless you’re under direct sunlight.

In fact, you could end up with eye strain or migraines by leaving the brightness cranked all the way up even when indoors. That means that lowering the settings to a more reasonable level will not only save battery life but also make you more comfortable during use.

Beyond that, turning Bluetooth, wifi, and location services when you’re not using them can further cut down on how much power your phone draws. It’s worth noting that some apps can’t function when you turn location services off, so proceed with caution.

Finally, minimize the number of push notifications that you allow. Not only are these annoying and a major hamper on productivity but they can also deplete your charge faster. This is because they light up the screen and trigger the vibration motor.

Battery Myths

Charging through your laptop will damage the battery

There’s a long-standing belief that you can cause harm to the battery of your smartphone if you charge it via the USB port of your laptop. This is completely unfounded and the opposite is likely true since USB ports charge your phone slower thus increasing its lifespan.

Batteries don’t perform well in the cold

Here we have another situation where the general public has managed to get things switched. Charging smartphone batteries in cool temperatures is better for your phone because it prevents overheating. The caveat is charging your phone in subzero temperatures (just don’t).

Leaving a charger plugged in wastes energy

If you’re the type to leave your power brick in the wall socket, don’t worry about it. There’s no power draw unless you’re phone is actually plugged in. We can cut you some slack for thinking this though as it used to be a major issue at one point.


As you can see, smartphone batteries are a lot more than just a brick of electrons. The innovation in past decades that took us from the NiMH in the Nokia 3310 to the dual Li-Po in the OnePlus 8T is truly amazing. Until next time, stay charged!