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An issue tracker for NREL's APIs available at https://developer.nrel.gov
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PVWatts V6 API cannot be used for inverters with efficiency below 90% #264

Closed grimsa closed 2 years ago

grimsa commented 2 years ago

We ran into a case where PV Watts API returned an Unprocessable Entity response with ["'inv_eff' must be between 90 and 99.5"] error.

The value we sent was 88 which seems to be correct for Growatt New Energy SPF 12000T DVM-US MPV inverter: image

Is the lower bound of allowed inv_eff values (currently 90) something that impacts the estimation logic, or is it an arbitrary value above which most/all inverters should fall? If the latter, could it be lowered to something below 88 to make it possible to use the API with a wider range of products?

Full request for reference: https://developer.nrel.gov/api/pvwatts/v6.json?api_key=<redacted>&system_capacity=1.0&module_type=0&losses=12.822227857000012&array_type=1&tilt=22.62&azimuth=0.0&lat=38.6550839&lon=-121.4376944&dataset=nsrdb&timeframe=monthly&dc_ac_ratio=0.3375&inv_eff=88.0

cpaulgilman commented 2 years ago

@grimsa This is an inverter for off-grid PV-battery systems. PVWatts is designed to model grid-connected PV systems with no storage. Other Growatt inverters designed for grid-connected PV systems have the more typical maximum efficiency values around 98%. Can you tell me more about how you are using PVWatts?

grimsa commented 2 years ago

@cpaulgilman Thanks for a quick update. You are right - it was a data entry issue on our side - the off-grid inverter in question should not have been in our database (i.e. we also only support grid-connected PV systems).