EcoFlow DELTA Max Smart Extra Battery- Make it a triple Double or triple the capacity of DELTA Max to 4032Wh or 6048Wh, longer runtime for your key appliances.- Charge anytime, anywhere DELTA Max’s Smart Extra Battery benefits from all the charging methods DELTA Max has, that means you can charge anytime, anywhere as long as your extra battery is connected to DELTA Max. Once connected, they’ll charge/discharge in unison, keeping the battery percent level across both units.- Ready for any emergency Get a 1800W DC fast charge with EcoFlow Smart Generator (sold separately). Just plug the generator directly into your extra battery via the extra battery port. This works even when disconnected from your DELTA Max.- Stay informed The Smart Extra Battery has a bright LCD screen on the front of the unit giving you all the info you need. Output, input, remaining charge and time remaining.