Hi i have the exact same problem. Vita3g completely charged and powered off in airplane mode. After 1 day power it up its lost 10 percent charge. After 3 days power it up only 20 percent left After 5 days its dead. I changed the battery, no change I changed the motherboard, no change Now i left out all the 3g bits and its holding the same charge (50 percent) for the past 3 days. I ordered a replacement 3g modem from ebay (france) and with the new 3g modem it does not drain anymore.