Bypass diode failure

• A step drop in one string’s output that does not recover with cleaning.
• A module section running hot on a thermal scan (hot-spot or active diode).
• Output loss roughly in thirds — one, two, or three sub-strings of a module affected.

• Affected string current sits below siblings by a discrete step, not a gradual drift.
• The deficit is largely flat with irradiance rather than scaling smoothly.
• No matching irradiance/temperature anomaly — distinguishing it from soiling or shading.

Bypass diodes fail from thermal cycling, lightning-induced surges, or sustained activation under partial shading, often ending shorted (a permanent third-of-module loss) or open (loss of hot-spot protection). Because each module typically has three diodes, the signature is loss in multiples of a third.

A handful of shorted diodes across a plant is a quiet few-percent yield loss; left unaddressed, an open diode allowing repeated hot-spotting can escalate into module damage or a fire-risk event, turning a cheap diode swap into a module replacement.

NuraVolt benchmarks each string against its cohort and looks for the discrete, irradiance-flat step that distinguishes a diode failure from soiling or progressive resistance, then flags candidate strings for a targeted thermal inspection rather than a blind sweep.