I have battled battery drain related to an exchange server for some time now. I am pretty sure my exchange provider (Apptix) is partially at fault, since this started when they migrated us to a new server, but their help team is rather abyssmal and they are not able to pinpoint any issue on their end, claiming a lack of complaints.
I say partially at fault because I am able to use a ROM that has the stock android exchange (rather than Samsung exchange) and that works fine, as does my Nexus 7 and iPad, and everyone else's iOS and Motorola Droid devices. So I had a couple of theories:
1. Somehow, my exchange provider installed some extra security that is designed to recognize Samsung devices and try to work with KNOX or the old SAFE system to implement extra security, but on a ROM'd and Rooted device, those components are missing and exchange services just run in a loop.
2. The stock Samsung exchange services have some memory issue, where they will continuously sync because they run out of memory
3. The stock Samsung exchange services do not deal well with unread messages (I notice that it will not sync read/unread in real time until I launch the email app, whereas the stock android one will not sync read/unread until either I launch the app or a new email comes in.
I theorized about #2 and #3 because my problem seems to get much better if I use a ROM where the security settings of the exchange services have been removed. Drain is still there, and I think it may coincide with periods that I have unread emails, but I am not sure. Data usage is also much lower (Samsung exchange with security would use up to 10MB or more per hour), but not as low as when I use a stock android exchange services. Also, it appears that samsung android services (without security) is keeping the phone awake without actually using the CPU - so perhaps it keeps awake if there is a unread notification? Below are my battery stats.
So for those of you that read the long version - has anyone else experienced this? Has anyone had any luck figuring it out? And yes, I have tried removing and adding back the exchange account, removing the account through OWA. And to pre-empt the inevitable "use third party" - I like having an integrated exchange solution, where I can see calendar next to my gmail calendars.
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