Archive – Solar & Battery Storage Sizing & Payback Estimator (v1.0)

The calculator below is the Solar Choice’s original Solar & Battery Storage Sizing & Payback Estimator. Upon releasing a significantly more sophisticated version of this tool, we have created this page for anyone who wishes to access the older version for whatever reason.

Go to the new calculator

The biggest disadvantage of the calculator below is that all outputs are based only on a model of two days’ worth of energy consumption and solar production data, whereas our new version is based on a 365 day model. Other limitations include:

  • All outputs from this calculator are based on a 24-hour period, using the average of one year of solar data. (More sophisticated tools would use a full 365 days of data.) As a result, all results should be viewed as ‘ball-park’ figures to be checked against other sources. It also doesn’t take into account seasonal variance in energy consumption or solar output, or the different way that a home might use energy on weekends.
  • All financial calculations are based on fairly simple calculations and should be seen as indicative only. Outputs do not constitute recommendations or advice. Again, we recommend that you check the results from our calculator against those from other sources.
  • Currently, the calculator only works for Australia’s capital cities.
  • For the most part, battery degradation is not modelled in this calculator. The only exception is in calculating battery payback times, where we assume that the battery bank will operate for the first half of its life at 100% capacity and the second half of its life at 80% capacity.
  • Battery charge and discharge efficiency are not modelled either. Instead, we have a more general input field for ‘battery efficiency’.
  • The calculator assumes that the battery bank can always ramp up to meet household energy demand. This may not be the case in real life. It’s far more important to have a battery bank that can respond quickly to sudden increases in demand if you have an off-grid system. For grid-connected systems, the electricity grid will meet any excess demand not met by solar/batteries.

The outputs from the calculator below are indicative only and should not be taken to constitute financial advice.