I went through 3 Verizon units thinking my units were defective because most people on here kept saying the battery life I was getting was "normal" but I was not getting close to what reviews and posters were getting. With 4G on, Wifi when applicable, BT off, NFC off, screen at 30%, I would wake up at 7:00 AM and unplug and get home at 7:00 PM and with light usage 40 minutes screen time I had 15%-25% left at most. Not bad, I would make it through the day but in my opinion I was barely touching the phone. Previous phones such as my iPhone 5 in similar settings I was getting through the day but with at least 40%-50% in the tank, easily making it to the next morning.
There are a few reasons why the Verizon HTC One doesn't get great battery life, one being uniquely Verizon based is the fact that Verizon removed the power saving mode for some stupid reason. The One has a 2300 mah battery but it sadly doesn't use a lithium-ion polymer battery, which makes charging a long process (hours). A number of other phone makers artificially clamp display brightness just to set a better higher bound for battery life, and for example HTC?s display auto brightness function doesn?t have as much dynamic range as the slider being actuated manually. The result is a phone that?s brighter than it needs to be a lot of the time, which is in contrast to Samsung which has a screen that is often to dim. The screen for any smartphone is the biggest battery draw but HTC's bright screen kills battery. Every minutes I saw a 1% drop in battery when the screen was in use.
In contrast my S4 with similar setting from 7:00 AM to 7:00 PM I am getting through the day but have at least 60% left over, which could easily last through the next day.
I think HTC needs better screen management and switching to lithium batteries would greatly help