More battery life with it on "when low" vs always on

[Skulls138]

On my Lumia 1520.3, it says I have 11 hours with no saver, 13 with it always on, and 15 with it on low. A bug?

 

[CapoFantasma97]

Battery saver, you are drunk, go home...

 

[xandros9]

It tries to predict usage into the future, so I would treat those numbers with a grain of salt unless you have very consistent and predictable usage.

 

[gpobernardo]

The irony in the Battery Saver is that it needs to run in the background in background to collect data (such as average discharge rate) in order to determine the remaining battery life. Once "Always on (not recommended)" is selected, Battery Saver will (or at least should) no longer run in the background and therefore no longer collect the data it needs to determine remaining battery life. Thus the "estimated time remaining" in "always on (not recommended)" is most probably erroneous.

Additionally, the "estimated time remaining" is based only on the average discharge rate determined from the past ~30 minutes (Battery data sampling interval). So if you suddenly do some intensive graphics with your phone, the "estimate" would drastically change.

Bottom line, the app does "save" the battery (with the appropriate selected modes, of course) and the numbers it shows are mere "estimates".