From my recollection the OEM battery's are rated at 1480 which gives you about 16 to 18 minutes (whatever). Moving up to a 1680 battery for $112.86 would give you a couple minutes more of flight time (do the math). In my opinion its not worth it. I understand Spark can lift about 5 oz.'s, as for me, I'm looking into (CAD design) mounting two hobby shop type battery's side-saddled to the OEM battery in a thin casted carbon fiber or 3D printed clip-on enclosure, via extension cord, for considerably more flight times.