When you've got two quad-core processors, a 2k display, 3GB of RAM and a 4k camera... you can expect to have some battery struggles. The phone is equipped with a 2,550mAh battery. This battery is non-removable, so the days of swapping batteries are over.
You might remember that the previous model (The Galaxy S5) had a larger, 2800mAH battery. Samsung decided to go with the smaller battery, so that they could produce a slimmer phone. Slim shady might be happy about this, but I'm not.
Battery Life
It is unlikely that you'll be able to make it through the day without having to charge your Galaxy S6. Even when you're not using it and it's in standby mode, the phone seems to still drain quite a bit of power. Of course, with custom ROMs and Kernels, you'll have the ability to stretch the life out a bit, but out of the box you're probably looking a max of about 7-8 hours of use.
Heat
I was shocked at how hot the battery on this phone gets. It gets so hot that it's almost unusable without some kind of case. I actually was able to successfully bake a cupcake on the surface of the S6 after playing three hours of AngryBirds Seasons on it. I installed a battery temperature app and monitored the hottest and the coolest temperatures that the battery was putting out. This is the result.
The highest temperature of 144 degrees was reached when the phone was using GPS with Google Maps. I almost died.
How to Get The Most Out Of Your Galaxy S6 Battery
Power Saving Mode
Samsung offers an option called Power Saving Mod, which helps you save battery by making a few adjustments.
Save battery power by limiting the maximum CPU performance, reducing screen brightness and frame rate, turning off the touch key light, turning off Vibration feedback, and reducing the time before the screen is turned off when notifications are received.
Ultra Power Saving Mode
If Power Saving Mode still isn't cutting it for you, active ULTRA POWER SAVING MODE!
Save battery by applying a simplified grayscale theme to your Home screen and limiting the number of useable apps.
Dim the AMOLED Display
The AMOLED display in the Galaxy S6 works a little differently than an LED or LCD display. When the pixels are showing a darker color, they're using much less power. That's why you get much deeper blacks. When a pixel is showing black, it's using next to no power at all. This can give you a bit of an advantage when it comes to saving battery. Just use a dark background to relieve the stress on your phone's power.
Greenify
Greenify is a fantastic app that will work on both rooted and non-rooted phones. This app has tons of features designed to optimize you phone's performance, to get as much life as possible from your battery. It's constantly getting better as they add new features. There's a dedicated XDA forum that you can check out. You can also download the app right from the Play store.
Use these tips to get the most out of your battery life. You might also want to think about putting a custom ROM on your phone, with better battery management. Or just walk around with a really long extension cord so you can always be plugged in, you wall-hugger you.