To compare solar autonomy proposals, ask how each supplier models your location, nightly schedule and cloudy periods. A general runtime statement cannot establish performance for your site.
Location and seasonal assumptions
Which weather data and season are used? How are shading, panel orientation, temperature and local installation constraints considered? Send the location and site photos or drawings so assumptions can be checked.
Nightly load and cloudy periods
What operating and dimming schedule is assumed? What lighting level is maintained during poor weather, when does the controller reduce output, and how is battery recovery assessed? Ask for the calculation assumptions rather than a fixed autonomy promise.
Configuration and maintenance evidence
Ask how the proposed panel, battery and luminaire are matched, which losses and battery ageing assumptions are included, and how replacement access works. Request documents for the exact configuration; suitability and any performance terms need project review and written confirmation.
