lots of folks just use rechargeables. many reference eneloops.
i've had decent luck with the powergenix NiZn AAs, they actually stay above 1.5V for their entire duty cycle (which for me could be two gigs with the G50, though i go with fresh ones each gig just because).
i mounted them to a pedaltrain nano with my G50 receiver, so i'd always have charging up batteries ready to go.
one caveat: do not
leave the batteries in the charger when it's not charging, or they will
die an early death.