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The consumption profile on the Energy page needs to be “before solar”, i.e., the customer’s actual consumption - not the net energy imported from the grid (ie reduced consumption due to existing solar). See more about this here.
The solar export earnings from the existing system do not contribute towards the payback/ROI of the battery
The payback periods for battery-only upgrades on existing solar are usually quite long.
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Add the existing panels and inverter to the system design, just as you would for quoting new ones.
Then on the Solar and Battery Designer page, click the 'pre-existing' box next to each inverter and MPPT. That way their energy production is factored into the site and battery charge, but they are not added to the quote price.
Click add inverter
Select the hybrid inverter you wish to use
In the PV module section, select ‘Blank panel’
Check the ‘pre-existing’ box next to the panel name
Add the battery
Do not place the ‘Blank panel’ on the map
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Consumption profile must be the Gross consumption (before solar)
Make sure that the consumption profile you set reflects the total loads. If the customer has solar already, simply entering the consumption profile as the amount of energy they import from the Grid will not reflect how much energy they are actually using. Similarly, uploading .csv data from their nett meter will not suffice, because it is much lower than their actual consumption. It isn’t possible to accurately calculate their total consumption by taking the grid import and factoring in the assumed production from the existing solar array, because the actual insolation at the time the grid meter data was captured is different than the insolation in the meteonorm normalised data, there are inaccuracies. For example, When the recorded solar export > modelled solar production, then the calculated load is negative.
If they have a meter linked to their inverter that records gross consumption, please use that data instead. Alternatively, you can use a typical consumption profile from the library and estimate the average daily kWh.