Deficiencies Identified in the Process of Quality Assessment

Deficiency Cause Manufacturer Response
Failure Modes
~20% LED failure rates Variance in wire diamater to LEDs New LED provider identified
~25% reduction in light output Assembler deviated from design specification, using material for diffuser in front of LED array that fogged in the presence of sunlight, leading to very noticible reduction in light output. Manufacturer instructed to re-instate specified material
Batteries overheating Co-location of batteries with solar panel, resulting in heating during charging Product redesigned to achieve passive cooling
Battery will not charge Unknown Unknown
Battery will not charge on hand-cranked light Counterfeit (non-rechargable battery) Deliberate
Battery will not charge on "shake light" Counterfeit (non-rechargable battery) Deliberate
Short battery life Use of inferior batteries Life cycle testing of different suppliers of batteries, change from lead-acid to Ni batteries
Internal condensation High charge rates causing high temperatures, in high humidity areas Lower charge rates from 0.5-1C to <0.2C and/or conformal coating on circuits for waterproof design
Warped solar panels Thin black plastic frame overheats in sun Change color, thickness and/or shape of panel frame
Reduced light output Likely failed voltage regulator TBD
Vulnerability to rainwater damage Electronics short if light left in rain. Light and connections not protected from rainwater that would run down cable connecting it to rooftop PV cell. TBD
Cracked junction of gooseneck and body Use holding by gooseneck, not lamp body, weak structural joint Make joint thicker, include instructions on proper handling
Sub-optimal Design or Manufacturing
Non-uniformity of light distribution Directionality of LEDs Varied type and location of LEDs and added switching to provide narrow and wide modes of illumination
Insufficient operating hours between charges Battery under-sized Upgraded to battery with greater capacity
Dead circuit Poor soldering during manufacture TBD
Wiring damage Wires installed in goosneck with no slack. Repeated adjustment stretches and ultimately breaks wires. Unknown (slack should be added)
Undercharging of battery Solar cell voltage and batteries mismatched Unknown