Battery drains very quickly on Samsung Galaxy S5 I have purchased a Samsung Galaxy S5 from the store. I open it and I begin by charging it for the first time, but without turning it on. The battery was 61%, so I waited until 100%. After that, I turned on the phone and proceeded to set it up. The version of Android was 5.0 Lollipop (I don't know how this is possible as I thought I need to update it myself from 4.4.2 to 5.0).

While I was entering in the information for the first time, the battery suddenly fell from 100% to 95% in just 5 to 10 minutes, during the first steps where I had to create a Google account and set up my phone options.

I heard rumors that 5.0 Lollipop drains the battery quickly so I downgraded to 4.4.2 KitKat with the hope that it'll fix the battery problem. I downgraded successfully without error.

I have the same problem—the interesting thing is that I didn't download more than 5 apps. I only have Skype, Facebook, Messenger, WhatsApp, Viber and Instagram. All the other apps are from the phone itself.

Whenever I go to WhatsApp to check messages or chat (or anywhere else), the battery falls 1% after 3 minutes. All of the NFC options, location options and other unnecessary options are turned off. The brightness is also on low. In 15 minutes of use I notice that the battery falls from 80% to 65% or 60%.

I have already done a factory reset twice, whilst I was downgrading to KitKat 4.4.2.

I'm a new user of a Samsung Galaxy S5. Is this normal or abnormal? What is the problem and how can I resolve it?
"....the battery suddenly fell from 100% to 95% in just 5 to 10 minutes"


That's perfectly normal and no cause for concern. Reasons for this are well explained in this XDA post  Your battery gauge is lying to you (and it's not such a bad thing). Summarizing from this post:


  As explained at Battery University, "The time at which the battery stays at [maximum charge] should be as short as possible. Prolonged high voltage promotes corrosion, especially at elevated temperatures."


so


  This is why many new phones will "lose" up to 10% within a few minutes of coming off the charger. The reality is that the battery was only at 100% capacity for a brief moment, after which the battery management system allowed it to slowly dip down to around 90%


so how do OEM's deal with this situation?


  The phone manufacturers essentially have three choices:
  
  
  Use older charging styles which actually maintain a full battery, thereby decreasing its eventual life
  Use new charging methods and have an accurate battery gauge
  Use new charging methods and have the inaccurate battery gauge
  
  
  Option one has clearly fallen out of favor as it prematurely wears devices. Option two, while being honest, would most likely be met with many complaints. After all, how many people want to see their phone draining down to 90% while it is still plugged in? Option three therefore offers an odd compromise. Maybe phone companies think that users will be less likely to worry about a quick drop off the charger than they will worry about a "defective" charger that doesn't keep their phone at 100% while plugged in.


So, it's normal and have seen it happen in every phone (four of them) I owned in last four years