What I'd say in support of over-sized but still light lithium battery Rx packs, is the very low self-discharge rate and the predictability which gives me far more peace of mind than I ever experienced before when accumulating Rx pack time over a weekend or event. And so far nothing to ruin the honeymoon.

An alternate to the Zippy 700 LiFe could be say a 500mAh 2S LiPo (36g) with a compact 5A BEC at 11-12g for a hair under 50 grams, about equal to two AA NiCD cells plus solder and harness. But the Zippy 700 rocks for smaller aircraft.