We don't support any extended batteries because of their added bulk, and even more critical, mass.
Instead, lots of our customers prefer to use a "battery eliminator" that allows their handhelds to be connected to a cig lighter (or hard-wired to 12V) all the time, thus saving their batteries for when out of the Jeep. As an added benefit, using the battery eliminator also allows the handhelds to operate at the highest power level all the time, and with the addition of a speaker/mic, at a louder volume, without worrying about running out of juice.
You can find battery eliminators very affordable on Amazon.