The DELTA MAx Smart Battery can double or triple the capacity of DELTA Max to 4032Wh or 6048Wh, giving you longer runtime for key appliances. DELTA Maxs 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, theyll charge/discharge in unison, keeping the battery percent level across both units. 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. . Charge anytime, anywhere. | Ecoflow Technology Ltd DELTA Max Smart Extra Battery