Not all the time but every so often my battery drains really quickly. It might be at 80% at night and at 20% the next morning and if I look at the battery usage stats the OS has used the majority of the OS. If I restart the phone it will usually be ok again.
Is there anyway of finding out what part of the OS is causing the issue or how can I stop it? Its not an issue if I am able to charge the device as soon as I relaise but sometimes I have to go out and then have a practically dead phone for the day. This can also happen at other times as well but I usually just check it periodically in case the OS is using the battery a lot.