Battery drain rates are very dependent on usage patterns and sometimes the most insignificant settings changes can lead to well hidden sources of current consumption.
So my advise is to try to remember if you made any changes in your applications or usage patterns right before or after starting to use Xposed, as your answer my lie there.
Also try to identify if the high drain occurs from Xposed itself or one of the modules, by deactivating and/or uninstalling modules and Xposed. Please be very careful that usage patterns might easily tip your conclusions off.
To somehow prove what I'm saying here, I've noticed that on a high usage day, my N5 can last as low as only 8-10 hours on a charge, while on a low usage day, after 12 hours since unplugging, it still has at least 80% of the original charge.
Have a nice day!