Battery capacity (Wh)
Watt-hours is the only number that matters when comparing batteries. Multiply volts × amp-hours: the standard 48V 13Ah pack is 624 Wh — fitted across Greaser Classic / Springer, Outsider 4.0, Vacay, and Ponyboy. The 48V 17.5Ah pack (Greaser Limited, Outsider 5.0, Outsider MX) is 840 Wh, about 35% more range. The Outsider 5.0 can be optioned with an extended 48V 20Ah pack — 960 Wh.