Kadansky Logo

Personalized Computer Services

(617) 484-6657


How I Work





Practical Computer Advice
from Martin Kadansky

Volume 17 Issue 2

February 2023

Your Cell Phone: Reduce Screen Brightness, Extend Battery Life

The Problem

Almost everyone I know who uses a cell phone or tablet wishes that their battery would last longer on a single charge. And even when your device is plugged into a charger, there are some situations where the battery level can steadily decrease!


There are thousands of articles and instructional videos that you can find online with dozens of suggestions about power-related settings that you can adjust, including turning off unnecessary notifications, disabling your personal hotspot, controlling which of your mobile apps are permitted to run in the background, installing recent updates, and more, all of which depend on your particular needs and situation.


While often very good, that advice can get a bit complicated to explain, not only why you would adjust those things but also how, especially given the many different versions of the operating systems that you may have on your iPhone, iPad, or Android devices.


I have also noticed that there is one particular setting that isn’t frequently mentioned.


Screen brightness: A significant drain on your battery


I have found that, when appropriate, turning down the screen brightness on a mobile device can significantly reduce its battery consumption, and it can also reduce the time it takes to charge back up again.


I’m not suggesting that you permanently lower the brightness once and then never change it.


Instead, when you can remember to adjust it, I recommend choosing the lowest brightness level for each particular situation that still lets you comfortably use your device. For example, you might find that a lower level might work in a dark environment (driving in your car in the evening, in a room darkened for a Zoom meeting, etc.) and a brighter screen might work better during the day.


You will have to experiment a little, and the level you choose will depend upon a number of factors, but in general I’ve found that reducing the brightness to 75%, 50%, 30%, or even 25% can still be bright enough to use a device while noticeably extending its battery life and reducing the time it takes to recharge.


In particular, if you choose a very low brightness level and then walk out into bright sunlight, that combination may make your device’s screen so dim that you cannot use it at all, even to raise the brightness back to a workable level. If that happens, go back inside right away and increase it.


Common ways to adjust the brightness


On an iPhone or iPad:


  • Settings->Display & Brightness
  • Or open the Control Center (see below for how to find it via Google), and then swipe to increase or decrease the level for the “sunburst” (brightness) icon.


On an Android:


  • Settings->Display->Brightness
  • Or swipe down from the top, and then swipe the brightness control horizontally to adjust.


Replacing an older or failing battery


The rechargeable batteries in a mobile device do not last forever. Typically, after 3 to 5 years their ability to hold a charge diminishes. If your device still works except for the battery needing to be charged frequently and my advice above does not help, it is far less expensive to have the battery replaced than to buy (and move to) a new device.


One situation where my battery usually ran down, even while charging


I use my smartphone in my car to get driving directions. Such mobile apps use a combination of technologies that all consume power, including GPS satellites (to calculate my location), the cellular data network (to get the street maps via the internet), the screen (to show me the road ahead), and the speaker (to tell me about the next turn or two).


Using a GPS app runs down the battery a lot, so I always plug my smartphone into my car charger.


Even so, I started to notice that the longer the drive, the more likely that the battery level was lower when I arrived than when I started. That prompted me to think about the most significant thing that I could control (apart from not using driving directions at all): The screen. I found that by simply lowering the brightness, the battery level would be higher when I arrived, while the map on the screen remained clear. Thus I had the idea for this newsletter.


Where to go from here


For any of the searches below, replace “X” with the type or model of your device, e.g., iPhone, iPad, Android, Motorola, Galaxy, etc.


  • google: X screen brightness
  • google: X screen auto-lock
  • google: X battery drain OR extend
  • google: iphone ipad control center

How to contact me:

email: martin@kadansky.com

phone: (617) 484-6657

web: http://www.kadansky.com

On a regular basis I write about real issues faced by typical computer users. To subscribe to this newsletter, please send an email to martin@kadansky.com and I'll add you to the list, or visit http://www.kadansky.com/newsletter

Did you miss a previous issue? You can find it in my newsletter archive: http://www.kadansky.com/newsletter

Your privacy is important to me. I do not share my newsletter mailing list with anyone else, nor do I rent it out.

Copyright (C) 2023 Kadansky Consulting, Inc. All rights reserved.

I love helping people learn how to use their computers better! Like a "computer driving instructor," I work 1-on-1 with small business owners and individuals to help them find a more productive and successful relationship with their computers and other high-tech gadgets.

Printer-friendly version

Subscribe to this free newsletter

Go to the Newsletter Archive



To the Top

All original content copyright © 2002 - 2019 Martin Kadansky

Site designed and developed by and copyright © 2002 - 2007 ozbarron