Why is my phone battery draining so fast?

When you plug in your phone, electrons enter your phone battery from the power source, according to the National Center for Biotechnology Information (NCBI). These electrons attract lithium ions. Think of them as really tiny balls of lightweight metal. They travel inside the battery from the cathode to the anode. This charges the phone battery.

When the phone is disconnected from the power source, the lithium ions switch directions and travel from anode to cathode. Once all the lithium ions end up in the cathode, the battery will “die” because it’s no longer producing a circuit.

If your phone is using a lot of energy, or if it’s not using energy efficiently, the battery will drain faster. Here are some of the main factors that can cause it to drain fast.

Your screen is too bright

The brighter your screen, the more energy you’re using, according to a study from Purdue University.

Most phones have a feature that automatically adjusts your screen’s brightness to complement the lighting of your surroundings.

You don’t necessarily have to worry about reducing brightness while using your phone but think about reducing brightness when you’re not using it. One way to do this is to make the screen idle time as short as possible, which automatically shuts the screen off when you’re not actively using it.

Does dark mode use less battery?

Yes, using dark mode is generally more energy efficient. Dark mode is a feature some phones have where you can make the background of your interface darker colors. The study from Purdue University found that switching to dark mode when your screen is at 100% brightness can save up to almost 50% battery power.

You’re using data instead of Wi-Fi

Typically, Wi-Fi connections use less battery power than data connections, states The New York Times. Because constantly searching and switching connections between multiple towers typically uses more battery power. A weak Wi-Fi connection, however, could drain faster than it would if you had a strong connection, as it strains to remain connected to a weak signal.

Some phone settings allow apps to operate in the background, says The New York Times, so long as you’re connected to Wi-Fi or data, which would also contribute to a quicker draining battery.

You have poor reception

It takes energy for your phone to search for a signal, according to The New York Times, and it’s not necessarily going to stop searching on its own. Many underground, remote, and/or mountainous areas are prone to having poor reception, and it’s best to turn off your cellphone’s data while traveling through these areas to preserve battery life.

The phone is old or outdated

Modern smartphones that came out after 2017 have OLED (organic light-emitting diode) screens, which don’t have backlights like LCD (liquid crystal display) screens do. This allows the screen to draw less power when displaying darker colors, says Forbes.

Upgrading your phone to a modern model may be the simplest way to get the most battery-friendly features available.

Your phone is exposed to extreme temperatures

Extreme heat and cold can negatively affect how your battery operates, according to The New York Times. Specifically, it often makes it harder for the battery to hold a charge. Be mindful of keeping your phone warm when it’s below freezing and cool when it’s hot out.

You charged your phone too long

Reducing the amount of times you charge your phone to 100% can help prolong the life of your battery to a certain extent, says The New York Times.

And just as you might avoid overcharging, so do you want to stay away from letting your phone run completely low. Consumer Reports pegs 80% as the ideal charging limit for your battery. But it’s important to note that charging your battery will cause it to degrade over time.

Also important is where you charge your phone. As mentioned above, overheating can affect battery health and charging your phone under your pillow runs the risk of doing just that, says PCMag.

Always check for OS system updates

System updates can help your phone use battery energy more efficiently in many ways according to PCMag. For example, some modern operating systems have features that allow your phone to better limit background usage of programs, other updates let your phone control how much battery it uses while charging.

As technology continues to evolve, operating systems find ways to automatically make your phone’s energy usage more efficient, so it’s always good to make sure your operating system is up to date.

Modern lithium-ion phone batteries usually operate at full capacity for at least a year and up to five years (or between 500–1000 charge cycles), according to TechAdvisor. After that, their capacity will be reduced, meaning the older batteries won’t hold a charge as well or as long.

Daily charging and keeping the phone away from extreme temperatures (both hot and cold) will help prolong the life of the battery.

Understanding your phone’s battery capacity

Phone batteries are commonly measured in Milliamp Hours (mAh) or Watt Hours (Wh), according to Macworld. A higher number often suggests a longer battery life, but actual performance depends on the other factors explained above.

General battery capacity:

• 3,000 mAh (≈11 Wh): Generally, lasts about a day.
• 4,500 mAh (≈16.5 Wh): Often lasts one to two days.
• 5,000 mAh or more (≈18.5 Wh): Designed to last two to three days.

Where to find these numbers: iPhones don’t typically share these measurements; instead, they list battery life in hours based on usage. For Androids that do provide this information, you can usually find it in the settings or on the manufacturer’s website. If it’s not listed, some third-party review sites and teardown reports may provide them.

How to check your battery’s health

Knowing your battery capacity is sometimes helpful, but it doesn’t reflect your battery’s current condition. Over time, batteries degrade, reducing their ability to hold a charge. To get a clearer picture, check your phone’s battery health in its settings.

Options for doing so vary, but common steps for both iPhone and Android devices include going to settings, then battery. From there, you can select the appropriate option to check whether it’s charging normally and view other data, including its charge level.

When you start to see your battery draining as soon as you power it on, there may be some simple things you can do to extend the battery’s life. Here are a few ways to squeeze out a bit more time from your phone battery.

1. Keep away from extreme temperatures

Extreme temperatures are among the fastest ways to ruin your phone’s battery life. Keeping your phone at room temperature is ideal and be mindful of how hot your phone gets when it’s being charged. Again, avoid charging it under your pillow or clothing.

2. Keep the battery at roughly 80%

The longer you can keep your phone adequately charged between at 80%, the better.

Keeping it charged – instead of turning it off and on when you have a low battery –will help it better retain its power over the long run.

3. Use only the apps you need

Delete apps you don’t use to declutter your phone, turn the brightness down when you can and restrict background usage of nonessential apps. The more efficiently you use your phone, the longer its battery should last.

Many modern phones now include a “battery-saving” feature, which will automatically adjust elements of brightness and app usage to maximize your battery’s efficiency.

If your phone’s battery health indicates it’s for a replacement, the safest option is to schedule an appointment with a professional. Most modern smartphone batteries are not easily removable and attempting to replace them yourself can be complex. To get started, visit your phone manufacturer’s website for details on their battery replacement services. Typically, you’ll take your phone to a retail store or an authorized service partner or mail your device to the manufacturer for battery replacement.