Case Review: Why a Suizhou Rooftop PV Plant Chose Handheld Daytime EL Instead of a Drone

ⓘ This article is currently published in Chinese. An English version is being prepared — read the Chinese original.

A field review of a real C&I rooftop distributed PV project in Suizhou, Hubei, where the owner wanted an internal-quality check of modules on a cramped steel-sheet factory roof. Unlike the large Shenyang rooftop survey where UAV daytime EL was the right call, this project went the opposite way: the roof was too cluttered and the array too scattered for a drone crew to pay off, so the team used a single-operator handheld daytime EL unit instead. The article walks through the trade-offs behind that choice: why night-time blackout EL was ruled out on an elevated roof, how daytime imaging let the inspection run inside normal working hours without stopping production, how walking routes were planned so the inspection itself would not stamp new cracks into the modules, and why every image was bound to a module position to build a traceable archive for future comparison. It closes with honest limits: when a rooftop is actually better served by a UAV survey, and what a handheld-only approach cannot cover. The takeaway for owners of small and mid-size rooftop plants: matching the tool to the roof matters more than owning the fanciest tool.