To charge the battery in the Powerstation jumpstarter, according to the User Guide ( ), this is the type of extension cord you need. It will connect the Powerstation to any 120V AC power outlet -Extension-Pow...
Looking at the specs for the charging adapter provided above, it only needs 0.5A to 0.7A to charge the jump starter. Obviously it takes longer to charge the battery with this amount of current, but most probably it is suited to the type of battery (and battery management system) in the jump starter.