When i bought my IPAD 2ND generation, i bought a 29 watt charger so I would not see the battery deplete as I used the ipad while plugged in... Now. After upgrading to 12.1 , my battery level now routinely drops... before it would always stay at 100%... The fix for now is a hard rebot.... after the reboot battery goes back to 100%.. I have not changed anything... No background updates allowed, bluetooth off, siri is off, anything that would eat cpu is off...