This utility allows you to determine the breakeven point, and therefore the payback period, for a battery-only installation. Enter all the pertinent details about your propsoed installation into the various settings on the left-hand side of the screen. Click any of the information icons to get more details on each of the settings. Please only adjust the advanced settings if you understand what they are.

It is assumed that all of the energy stored in the battery each day is able to avoid you paying standard rate prices on your energy consumption that day.

The uppermost chart shows two lines: the grey line represents the cumulative costs incurred before any battery-only installation, and the green line, the cumulative costs with a battery-only installation. The initial value for the green line is the cost of the battery installation.

The reason both lines represent cumulative costs is to show the point in time where the costs to date both with and without a battery cross each other. This marks the breakeven point, from which point on, there is a saving to be made from having a battery. If the lines do not cross, then there are unfortunately no cost savings to be made.

The second chart shows visually, the expected reduction in battery capacity over time. This chart takes into account any minimum state of charge for the battery and also depth of discharge (if less than 100%).