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 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.
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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 nett 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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Hybrid inverters with a battery, but no panels
If you are upgrading an existing system by adding a hybrid inverter and battery but no solar panels, and just using it as if it were an AC-coupled battery, there is a solution:
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 net meter will not suffice, because it is much lower than their actual consumption. It is not 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 normalized 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. You can make an educated guess by checking the current consumption based on the current bill + (estimated solar generation from old/existing system - solar export from the old/existing system).
Note the average daily grid energy usage on the current bill
Note the average daily solar export on the current bill
Estimate the average daily production of the existing solar system.
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Total consumption = [existing solar production] - [solar export] + [grid usage] |
So if the site is using 10 kWh/day currently as per the energy bill and the site has an old 4 kW system that produces 12 kWh/day and is exporting 5 kWh/day, the actual consumption would be 12 - 5 + 10 = 17 kWh.