Exclusively from Outer Limits FPV:
7.2V 3500MAH Lithium-ion
Goggle Replacement Pack V2 Design
High Capacity 3500mah 2 cell 7.2v Lithium-Ion rechargeable battery, Version 2.
Replacement for most popular FPV goggles.
Increases "power on" times from the factory 2.5 hour range to 4+ hours of duration.
Charging is at 1/2 c or 1.75 amps using a suitable charger capable of charging Lithium-Ion cells or lipo batteries.
$28.50 each with free shipping in the continental U.S.