I have brand new Lumia 535 from my employer, with (as I was informed) brand new battery inside. Since this is the secondary phone for my, I'm currently using it in a very limited rate and most of the time it lies on the shelf, with screen turned off (phone locked), not used at all. Even so, the performance of battery is beyond any critics.
Here you have a comparison table for my recent tests -- my Lumia 535 with WiFi on/off compared to my wife's Lumia 735 (with WiFi off):
All tests were made during weekend, when both phones were not used at all or used at a minimum level (screen unlocled for 5-10 times, 1-2 phone calls, no Internet browsing, no music or video).
When my Lumia 535 has WiFi turned on, it needs to be fully charged once per each 24 hours. This is strange itself, because on Android-based devices I had similar experience, when battery was 12-24 months old. And with my limited usage of the phone, on brand new battery I could charge my phone once per two days. This is also supported by battery performance of my wife's Lumia 735, which is nearly one year old (and so its battery), but even so, with limited usage, it can stand 2-3 days without charging.
And as for turning WiFi off on-board my Lumia 535 things are getting even more worse, because phone's battery "dies" completely after only 9 hours of no use at all. This particular test was taken during night -- phone was charged to 100% on 23:00 and reached critical level of 3% on 08:30 next day. During that period of time it was lying in my back and I haven't unlocked its screen even once.
Lumia 735 has only 300 mAh bigger battery than Lumia 535, but it has bigger screen and uses LTE. And in my particular case it is also one year older and thus battery wear is significant. Even so, I'm getting a much, much better results, way beyond expectations on Lumia 735, while on Lumia 535 results are way below expectations (how can I use the phone, if I must charge it every 12 hours during minimal usage of it?).
Can anyone shed any light, what can cause such a bad battery performance in my Lumia 535? Is this a common problem, or maybe I have just got a brand new phone with not so brand new battery or with simply broken battery?
Edit: Battery Saver is turned off all the time on both phones and Lumia 535 uses (currently) only one SIM card, even though it is dual SIM phone. Screen brightness is set to
Minimum on both phones. Both phones uses different mailboxes, but the same sync settings (maximum -- i.e. every 15 minutes). Both phones has up-to-date software and all phone updates installed.