iPad battery drains in sleep mode on iOS4.2

I'm experiencing problems with battery drain while in sleep mode. I noticed the battery in my iPad was dropping overnight after upgrading to iOS 4.2. I charged my iPad to 100% then let it sleep for 6 hours. Even with WiFi turned off and all apps closed through the multitasking panel. When I powered it on, the battery was at 96%. Without using it, the battery was down to 62% in the next morning.