Want a smartphone with longer battery life? In a recent advertisement posted by Samsung on their official Facebook page, they are convincing potential buyers that the new S5 is the smartphone with the best battery life.
“No more low batt issues with Galaxy S5! Get over 24hours on 10% battery with the Ultra Power Saving Mode. Upgrade to a Galaxy S5 now!”

Here's an overview regarding S5's battery life:

Here are few tips which can also help on saving battery life:
1. Turn down your display brightness to save battery life
If there's one thing that's going to eat up the battery life on your Galaxy S5, it's the display. These phones push lots of pixels and a bright display will drain your battery quicker than just about anything. So at the very least, consider turning down your display as low as you can stand it.
Or, better yet, let the phone handle the brightness. It'll adjust things for you so you don't have to worry about it.
Also consider using the "Auto adjust screen tone" option, which Samsung says will save on your Galaxy S5's battery life by adjusting the brightness based on what's actually showing on the display.
2. If you have good Wifi, use it!
This is something we take for granted these days. But if you have the ability to use a good, solid Wifi connection, you should use it. This is especially true if you live in an area that has bad cellular connection. Or if you live or work in a bunker. Or a densely populated area. Or are at an event with a lot of other people.

Like a bright display, a bad cellular connection can be murder on your battery life. Ever wonder why it's getting hot in your pocket even when you're not using it? A bad connection could well be the case.
So do your Galaxy S5 — and your battery life — a favor. If you have good Wifi, use it.
3. And if you're on a bad network, get off it!

There's nothing more painful than having to hear the woeful tales of someone who hates their operator. We subscribe to what's known as the "90 percent rule." That is, you need to have a good connection 90 percent of the time, wherever you are. Wifi may well be able to take care of that. If so, great!
But a good percentage of folks can't be on Wifi all day. So it comes down to your operator (by which we mean the likes of Sprint, T-Mobile, Verizon, AT&T and the like, here in the U.S.) needing to be able to provide the service for which you're paying your hard-earned money. If your operator can't give you good service 90 percent of the time you need it — again, at home or at the office, it doesn't matter whcih — then you should consider switching operators.
Again, a bad cellular connection means you're wasting two things: Battery life, and dollars.
4. Check your display timeout
This is one Galaxy S5 battery life tip you might not have already known. There's a timer attached to your display. As soon as you stop touching the phone or otherwise using it, the timer kicks in, telling the phone when to turn off the display. Some apps can override this, of course. You can't have your phone going dark when you're in the middle of a game or movie.
But any time your phone's display is off is that much more time you can use the phone later. Typically screen timeouts are set at 30 seconds, but we've seen some set even longer by default. On your Galaxy S5, you can set the timeout to as low as 15 seconds.
Give it a try. You might be surprised at how much it saves on your batter life without being an annoyance.
5. Check your GPS accuracy mode
Fun fact: There's more than one way for your phone to know where you are. Back in the day it was a bit more binary. Either you fired up GPS to find your location, or you didn't. Assisted GPS (aka aGPS) would help with that some, using your operator's network to get a quicker fix on the GPS satellites. But GPS can still be a bit harsh on battery life.

But in the past few years, mobile operating systems have learned to use nearby Wifi locations to estimate where you are, and at a much lower power level. And you don't even have to be connected to a Wifi access point for it to work. There a Starbucks nearby? If the Wifi location is known, then an app (say, Google Maps) can find your relative location, without having to fire up the GPS receiver.
You have control over this, of course. The first is in your location settings. On your Galaxy S5, go to Settings>Network connections>Location, then tap on "Mode." Here you'll be able to choose from "GPS only," "Power saving" and "High accuracy." The first is pretty-self explanatory. It uses GPS. Power saving uses nearby Wifi access points and mobile networks to figure out where you are. And High accuracy uses all of the above to be a precise as possible.
If you're still worried about your phone sniffing around even when Wifi is turned off (and this isn't necessarily a bad thing), go to Settings>Wifi>Advanced and uncheck "Always allow scanning. That'll keep Google's location services from listening in for any of those location helpers.