Here's some real solution to improve your android's battery life (root needed, mostly).

First, I use Nexus devices. For those that don't know there are two big reasons to use those devices: updates and easily rooted.

So, first you need to root your device.

Install franco kernel. If your device is supported this will let you change your display gamma, and undervolt your cpu (undervolting can be tricky, but it can save a great deal of power especially when idling). There's more you can do, but I'd start with those.

Next, install greenify with xposed being optional if you want to hibernate system level daemons/processes (be very careful that you don't hibernate something that you will rely on to run as needed). Greenify simply lets you choose what you want to hibernate (nice ui, btw). Hibernation forces apps (or daemons/processes with xposed) to sleep in ram (but can be evacuated with either to zram or back to disk but you shouldn't ever lose app state), but not use any cpu time unless explicitly launched by you. This makes a big difference when idling as well.

Lastly, lux. This is what will give you much longer screen on times. You need to set anchors for interpolation (well, you don't HAVE to, but it will be more tuned to your liking that way), but that is super easy. When the screen is too bright/low you pull down the dash, click on the lux widget, move the slider until you are happy with the brightness and then long click on the lock. That sounds like a lot but it is really quick (although I haven't had to do it for awhile it only took a few seconds).

If you have a snapdragon SoC also grab snapdragon battery guru. I can't say how much it helps but it has been designed to keep the sensors in low power states (which can be helpful), and has been created by qualcomm, so they know what's best for their chips, as I see it.

These are amongst the changes I made which made a verifiable difference in the battery life of my Nexii.