Select the items that are most critical to keep powered when a power outage occurs.
In the "Critical Load Items" table below:

1. Choose a category in the first column (“Category”).
2. Choose an critical item in the second column (“Item”).
3. Enter a quantity in the “Quantity” column, if you will be powering more than 1 of the chosen item.

The following values will be calculated:

• Starting Watts. This is the initial power (“surge”) that devices with inductive motors draw when first powered on. For example, a refrigerator will switch its compressor on and off continuously to maintain temperature.
• Running Watts. This is the average sustained power that an electrical load uses while operating.

If you do not find a specific item in the Group/Item lists in the provided table, you can enter your own custom item in any of the last five rows.

1. Enter the item name in the "Item" column.
2. Enter a quantity in the “Quantity” column.

As you enter your critical items, the calculator will total the Starting and Running Watts for all of the items in each column ("Totals" row), and then compare these totals against the available wattage for each battery size. If the larger of the two totals is less than the watts provided by the battery, the color of the value will remain GREEN. If the total exceeds the available watts provided by the battery, the color of the value will change to GRAY.

The first battery size from the left in green is the minimum size required to meet your critical load requirements. If all of the battery sizes are gray, you will need to remove some of the critical items from the table (change the quantity to 0).