As Zero's Chief Technology Officer told us last year, there's more to battery technology than simple stated capacities. It's possible to refine each cell's chemistry to optimize capacity over raw current flow—and, yes, this is an oversimplification—to create the ideal balance between raw performance and capacity, which is the prime influencer of range. This year, Zero's packs have edged up slightly in capacity. For 2015, the top packs in the Zero S, for example, were the ZF9.4 and ZF12.5, signifying total capacities of 9.4 kWh and 12.5 kWh, respectively. This year, the packs are 9.8 and 13.0 kWh capacities. Adding a Power Tank to any of the applicable models (everything but the FX) results in 15.9 kWh total capacity. You could power a small city with that!