Just did some research on your problem also axxxo,you have probably come across this in your search but ill post it anyway
Copy & Paste
Q . Can I maintain a wireless connection while I change the removable battery?
A . No. When swapping batteries, the connection and any unsaved data will be lost. The Back Up battery will not maintain the wireless connection or any unsaved data.
Q . What is the Back Up battery for and how long will it last?
A . The Back Up battery is not used to power the device. This internal battery is only intended to maintain stored memory during a battery swap of the main removable battery. The Back Up battery will last up to 10 minutes. If the Back Up battery is depleted and a main battery is not being used, the device will perform a hard reset and data that is in RAM will be lost.