If you have a larger energy demand, want additional backup power duration at a single point, or want to offset a greater amount of solar generation, then you can expand your storage capacity by plugging one or more Orison Tower+ into the Orison Tower. The expansion units cost less by leveraging the power electronics and networking capabilities of the master unit.
For example, a modern, energy efficient refrigerator/freezer uses about one kilowatt-hour per day so a single Orison Panel or Tower would keep it going for two days in case of a blackout. If you wanted to ensure longer backup, adding one secondary unit could extend it to four days.
The number you install depends on how much energy you use per day and how many devices you’d like to maintain operational during a blackout. On a single master Tower unit, you can add up to five Tower+’s for a maximum storage capacity of 13.2kWh.