Due to me not maintaining power on the IBBS backup battery, it totally drained and is not rechargeable. Sort of forgot about this requirement over the years. Ordered a replacement battery and pulled the IBBS from the airframe. Four screws to remove the access plate, the battery is easily removed, and the new battery put into place.
Re-Installed the IBBS and made sure the Always On Bus is actually on, this provides the needed 2A trickle charge from the main battery to keep the IBBS battery alive.
