The GR5 AA battery pack assembly holds 4 AA batteries to provide a backup power supply for the GR-5. The battery pack snaps into place on either side of the unit. To replace the batteries, simply slide the panel off the battery pack, and insert new batteries. The battery pack is not designed to use rechargeable batteries.
When using the GR5 AA battery pack assembly, the unit should not be in transmitter mode. However, it is possible to hot swap a battery pack out, as long as the other pack still has a good charge. There will be no loss of data. The battery life will vary based on the type of batteries used and the duration of use.