> Quick answer: The welding quality of LiFePO4 cell tabs affects internal resistance and cold-weather performance, though no direct evidence links poor welding to these effects [1][2][13]. Poor electrical connections increase resistance, reducing system efficiency and reliability.
While research does not directly address the relationship between tab welding quality and internal resistance or cold-weather performance in LiFePO4 batteries used for solar lamps, it provides indirect evidence that poor manufacturing practices can compromise system reliability [1][2][12]. This article explores how these factors interact to impact battery performance.
Understanding the Role of Tab Welding Quality
The integrity of the electrical and mechanical bond between the tab and the battery electrode directly influences internal resistance and cold-weather performance in solar lamps. Poor welding can increase internal resistance, leading to reduced efficiency [1][24].
Impact on Internal Resistance
Internal resistance is a critical factor affecting the overall performance of LiFePO4 batteries. When tabs are poorly welded, it creates high-resistance points that impede current flow, reducing system reliability and efficiency [1]. Increased resistance can also lead to localized heating, further degrading battery performance.
Thermal Management and Performance in Cold Weather
LiFePO4 batteries are known for their stability and safety but remain sensitive to temperature extremes. High temperatures accelerate degradation through thermal cycling, causing material expansion and contraction that leads to microcracks and reduced lifespan [13][14]. Conversely, cold temperatures increase internal resistance, reducing available capacity and power output.
Cold Weather Effects
In cold weather, the increased internal resistance can lead to lower discharge capacities in batteries. Poor welding quality exacerbates this issue by creating high-resistance points that further reduce performance under stress [24].
System-Level Performance and Reliability
The reliability of solar systems depends on robust materials and proper integration. Unproven materials and inadequate testing can result in early field degradation, especially under real-world conditions [2]. High-quality welding is crucial for ensuring the longevity and efficiency of LiFePO4 batteries in solar lamps.
Thermal Management Solutions
One patent describes a solar lighting fixture with a heat sink to prevent overheating, which can damage charging circuits and battery components [18]. This underscores that thermal management is vital, and any defect—such as poor welds creating high-resistance points—can further degrade performance in cold or hot conditions.
Material Resilience and Manufacturing Quality
Material resilience is not just about chemistry but also structural integrity and manufacturing quality. Poorly welded LiFePO4 cell tabs may be more susceptible to mechanical stress during thermal cycling, leading to delamination or increased resistance over time [7][17]. This is particularly critical in cold climates where materials contract and may fracture at weak joints.
Self-Healing Properties
One advanced solar technology, TOPCon modules, exhibits „metastable resilience” under UV stress, meaning that degradation is reversible [7]. While this finding pertains to photovoltaic cells, it highlights the importance of real-world testing over lab predictions. This suggests that even if welding quality is suboptimal, other factors like thermal management or material resilience might compensate.
Critical Gaps in Research
Despite these insights, there are critical gaps in current research:
- The temperature range at which LiFePO4 batteries lose performance due to cold.
- The effect of internal resistance on cold-weather discharge capacity.
- How welding quality influences resistance in lithium-ion cells [2].
Testing Standards and Real-World Conditions
Experts disagree on the adequacy of current testing standards. One study argues that UV testing standards need amplification to reflect real-world conditions, especially for high-efficiency modules [17]. This critique extends beyond battery tab welding but underscores the importance of comprehensive testing.
Conclusion
While the provided excerpts highlight the importance of material quality and thermal management in solar systems, they do not provide direct evidence on how welding quality affects internal resistance or cold-weather performance. Indirect evidence suggests that poor electrical connections can degrade system efficiency and reliability [1][24].
References
- [1] PV_Connectors_Energy__075705d0 — authority
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of some metals to high humidity and other environmental stressors; – Supply-chain pressures that lead to cost-cuts in manufacturing, including materials substitution and reduction; – Prevalence of low-quality replacement connectors that are vulnerable to ingress of moisture /and particulates. A Four-Part Investigation Our research spans these topic areas: Onsite inspections include visual inspections for evidence of cross-mating, separation or loose connections, and signs of heat deformation; and thermal inspection via a handheld long-wave infrared camera. Onsite data collection will include connector type, manufacturer and serial number, if known, location of connector in the array, and site metadata, including module make and model, system age, climate zone, exposure to extreme weather, etc. This task will also include development of a master spreadsheet to ensure thorough and consistent data across multiple sites. Connectors removed from photovoltaic systems as a result of onsite inspections, commercially off-the-shelf connectors and connectors obtained via the project’s mail-in program, will be subjected to materials characterization and forensics analysis. The COTS connectors will represent a statistically significant number of each type, based on such data as market share, unit price, morphology and country of origin, and will provide important data on the variation in quality of connectors being sold in the US. Techno-economic analysis (TEA) data will be collected in p
- [2] UL_To_Bring_New_Science_To_PV_Module_Material_Electronic_Design__74bbbc20 — magazine
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# UL To Bring New Science To PV Module Material Performance & Reliability Source: Blog/Web URL: https://www.electronicdesign.com/news/industry/article/21198668/ul-to-bring-new-science-to-pv-module-material-performance-reliability Author: Date: 2015-10-27 The U.S. Department of Energy SunShot Initiative has awarded $1.35 million funding to UL to further develop new scientific methods for predicting PV module material performance and reliability over time. In partnership with several leading research companies and institutions, this project seeks to provide data on polymeric backsheets (part of the PV module) that correlates long-term field reliability with accelerated laboratory testing. There have been many reports of PV modules with visibly degraded backsheet in early years of installation. This is due to the market pressures on keeping costs down while maintaining aggressive product development that are driving use of materials and combinations of materials with unproven durability characteristics, as well as reliance on current testing that does not factor in long-term durability in actual installed environmental conditions. This SunShot Initiative Award will fund laboratory accelerated testing correlated to actual backsheet degradation in fielded PV modules. The results will benefit module manufacturers to optimize design strategies. Additionally, the results of this project will enable deeper understanding of the reliability of backsheets and will reduce the uncertainty
- [7] TOPCon_solar_modules_show_self-healing_under_UV_stress__62706250 — magazine
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# TOPCon solar modules show self-healing under UV stress – pv magazine Global Source: Blog/Web URL: https://www.pv-magazine.com/2026/03/10/topcon-solar-modules-show-uv-induced-degradation-recovery-study-finds/ Author: Emiliano Bellini Date: 2026-03-10 A group of researchers from China’s Nanchang University and solar module manufacturer Trina Solar have conducted a series of experiments to assess the impact of ultraviolet-induced degradation (UVID) on the performance of tunnel oxide passivating contact (TOPCon) solar modules and have found that this panel type can offer “metastable resilience” in real-world operation. “Our lab-to-field studies confirm that UVID in TOPCon is a light-recoverable metastable effect with no impact on real-world energy production,” the research’s lead author, Zhiwei Li, told pv magazine. “This is critical for improving investor confidence and bankability, and establishes a clear reliability understanding for the industry.” The researchers conducted UV accelerated aging tests on TOPCon solar cells using a HY-UV-4225 chamber equipped with a metal halide lamp emitting in the 280–400 nm range. During these experiments, the UV intensity was set to 180 W/m², and the module temperature was maintained at 60-65 C, with the samples being placed under short-circuit conditions in a chamber at 50-60 C and exposed to a cumulative irradiation dose of 2 kWh/m² from an 800 W/m² light source spanning 300–1200 nm. The cells were sandwiched between standard module glas
- [12] Impacts_of_PicoPV_and_Consumer_Research_-_energypedia__2ed9d7cd — authority
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# Impacts of PicoPV and Consumer Research Source: Blog/Web URL: https://energypedia.info/wiki/Impacts_of_PicoPV_and_Consumer_Research Author: Date: 2018-08-01 Impacts of PicoPV and Consumer Research Overview As experience with other renewable technologies show, lack of social acceptance and incongruity with cultural values and norms are common barriers during the implementation phase. Therefore, it is important to investigate in users needs and behavior patterns. Additionally, experience shows that laboratory test have to be complemented with field tests in order to test the solar lanterns under real-life conditions. Due to the fact that many bad quality products exists, it is also important to test selected products in a field test. GIZ Energising Development has conducted various tests in different countries, such as Bangladesh, Bolivia, Ethiopia, Mozambique, Nicaragua, Peru, Senegal and Uganda. Approaches of these tests differ, results and outlook are presented within this articles. Performance of Solar Lamps More than 100 firms are offering PicoPV products in developing countries today, but most products are of very low quality, with serious implications for consumer trust in the new technology. Early lab tests have focused the awareness of governments and donors on the importance of quality control and customer information – however, field tests in sufficient countries with sufficient sample sizes are needed for a better understanding of PicoPV performance under real-lif
- [13] Solar_Photovoltaic_Performance_and_Efficiency_Basics__974f2aa6 — authority
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heat. – Temperature—Solar cells generally work best at low temperatures. Higher temperatures cause the semiconductor properties to shift, resulting in a slight increase in current, but a much larger decrease in voltage. Extreme increases in temperature can also damage the cell and other module materials, leading to shorter operating lifetimes. Since much of the sunlight shining on cells becomes heat, proper thermal management improves both efficiency and lifetime. – Reflection—A cell's efficiency can be increased by minimizing the amount of light reflected away from the cell's surface. For example, untreated silicon reflects more than 30% of incident light. Anti-reflection coatings and textured surfaces help decrease reflection. A high-efficiency cell will appear dark blue or black. Determining Conversion Efficiency Researchers measure the performance of a PV device to predict the power the cell will produce. Electrical power is the product of current and voltage. Current-voltage relationships measure the electrical characteristics of PV devices. If a certain "load" resistance is connected to the two terminals of a cell or module, the current and voltage being produced will adjust according to Ohm's law (the current through a conductor between two points is directly proportional to the potential difference across the two points). Efficiencies are obtained by exposing the cell to a constant, standard level of light while maintaining a constant cell temperature, and measuring t
- [14] How_long_do_residential_solar_panels_last_pv_magazine_International__a1e59f16 — authority
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materials in their glass, encapsulation, and diffusion barriers. All panels also suffer something called light-induced degradation (LID), in which panels lose efficiency within the first hours of being exposed to the sun. LID varies from panel to panel based on the quality of the crystalline silicon wafers, but usually results in a one-time, 1-3% loss in efficiency, said testing laboratory PVEL, PV Evolution Labs. Weathering The exposure to weather conditions is the main driver in panel degradation. Heat is a key factor in both real-time panel performance and degradation over time. Ambient heat negatively affects the performance and efficiency of electrical components, according to NREL. By checking the manufacturer’s data sheet, a panel’s temperature coefficient can be found, which will demonstrate the panel’s ability to perform in higher temperatures. The coefficient explains how much real-time efficiency is lost by each degree Celsius increase above the standard temperature of 25 degrees Celsius. For example, a temperature coefficient of -0.353% means that for every degree Celsius above 25, 0.353% of total production capability is lost. Heat exchange drives panel degradation through a process called thermal cycling. When it is warm, materials expand, and when the temperature lowers, they contract. This movement slowly causes microcracks to form in the panel over time, lowering output. In its annual Module Score Card study, PVEL analyzed 36 operational solar projects in Ind
- [17] UNSW_Next-gen_solar_module_could_degrade_faster_than_expected__bfa0f162 — authority
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performance limits. UNSW research has previously revealed atomic-scale self-repair mechanisms in silicon solar cells that can partially offset UV-induced damage, but these mechanisms may be insufficient to counteract the elevated UV doses delivered by tracking systems and high-irradiance locations to next-generation cell architectures over multi-decade operational periods. “One of the key messages from our paper is that the UV testing standards need to be amplified or changed,” Dr Poddar added. “With new high-efficiency PV technologies being rolled out so quickly, we need to ensure the standards reflect real-world conditions.” The researchers emphasise that the new modelling tool is designed to help manufacturers, developers and asset owners make better-informed decisions throughout the project lifecycle. UNSW believes that, before installation, developers could use the global UV map data to conduct more rigorous accelerated UV stress testing on candidate modules, selecting products that demonstrate resilience to the specific UV exposure profile of the deployment location and mounting configuration they intend to use.
- [18] US6406163B1_-_Solar_cell_lighting_fixture_integrated_with_heat_sink__19b9a52e — patent
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cell panel light shade, bulb, battery components within the bulb (containing charging circuit and battery and a mounting member. – the purpose of said mounting member is for the fixture to be either directly buried in the ground, or provided at the top of a post, in a mechanical equipment, or to a vehicle including a automobile, a sea vessel or an aircraft. – Said member may be also provided in a form of an underground post or ground tapered support. – the light shade of the solar cell panel and the bulb are integrated that encourages heat to build up inside the bulb due to hyperthermal effect when the solar cell panel absorbs solar energy. Since the heat can not be effectively dissipated, the performance of the charging circuit and cell components is vulnerable to damage or failure. – the primary purpose of the present invention is to provide a solar cell lighting fixture integrated with a heat sink. – the prevent invention is for adaptation to a post lantern, a garden light, a wall fitting, or a vehicle including an automobile, a sea vessel or a aircraft, or a bicycle, a motorcycle, a portable light or other types of lighting fixtures. – a ventilation space is provided between utmost top and bulb of the lighting fixture of the present invention. – the utmost top of the lighting fixture accommodates an upper lid of a solar cell panel. – Battery components such as a secondary cell or a battery capacitor, and a charging circuit or device to convert electric energy into optical
- [24] Preventing_Electronic_Corrosion_in_Solar_Lights_-_Lighting_Global__2847d2ff — authority
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# Preventing Electronic Corrosion in Solar Lights – Lighting Global Source: Blog/Web URL: https://www.lightingglobal.org/preventing-electronic-corrosion-in-solar-lights/ Author: Jen Date: 2013-09-27 Preventing Electronic Corrosion in Solar Lights Lighting Global has published the 14th issue of the Technical Briefing Notes titled “Protection from the Elements Part III: Corrosion of Electronics“. This is the third article in a four-part series examining the environmental durability of pico-powered lighting products. The article describes the chemical processes and environmental mechanisms of electronic corrosion in a solar lighting system, and provides steps manufacturers can take to increase the corrosion resistance of their products. It notes that most pico‐powered lighting products are exposed to intense sunlight and heat on a daily basis. They are also continually moved around because of their portability rendering them vulnerable to drops and spills. Furthermore, they get dirty from ground contact and rough handling, and many will be exposed to water in the form of rainfall, moisture in the air, and groundwater contact making their components vulnerable to corrosion. “The electronic nature of pico‐powered lighting products coupled with their typical service environment creates an atmosphere that can be very conducive to corrosion. The batteries, electronic circuit boards, LED lights, and multiple external connectors (for wires between product components) are all potentiall
of some metals to high humidity and other environmental stressors; – Supply-chain pressures that lead to cost-cuts in manufacturing, including materials substitution and reduction; – Prevalence of low-quality replacement connectors that are vulnerable to ingress of moisture /and particulates. A Four-Part Investigation Our research spans these topic areas: Onsite inspections include visual inspections for evidence of cross-mating, separation or loose connections, and signs of heat deformation; and thermal inspection via a handheld long-wave infrared camera. Onsite data collection will include connector type, manufacturer and serial number, if known, location of connector in the array, and site metadata, including module make and model, system age, climate zone, exposure to extreme weather, etc. This task will also include development of a master spreadsheet to ensure thorough and consistent data across multiple sites. Connectors removed from photovoltaic systems as a result of onsite inspections, commercially off-the-shelf connectors and connectors obtained via the project’s mail-in program, will be subjected to materials characterization and forensics analysis. The COTS connectors will represent a statistically significant number of each type, based on such data as market share, unit price, morphology and country of origin, and will provide important data on the variation in quality of connectors being sold in the US. Techno-economic analysis (TEA) data will be collected in p
# UL To Bring New Science To PV Module Material Performance & Reliability Source: Blog/Web URL: https://www.electronicdesign.com/news/industry/article/21198668/ul-to-bring-new-science-to-pv-module-material-performance-reliability Author: Date: 2015-10-27 The U.S. Department of Energy SunShot Initiative has awarded $1.35 million funding to UL to further develop new scientific methods for predicting PV module material performance and reliability over time. In partnership with several leading research companies and institutions, this project seeks to provide data on polymeric backsheets (part of the PV module) that correlates long-term field reliability with accelerated laboratory testing. There have been many reports of PV modules with visibly degraded backsheet in early years of installation. This is due to the market pressures on keeping costs down while maintaining aggressive product development that are driving use of materials and combinations of materials with unproven durability characteristics, as well as reliance on current testing that does not factor in long-term durability in actual installed environmental conditions. This SunShot Initiative Award will fund laboratory accelerated testing correlated to actual backsheet degradation in fielded PV modules. The results will benefit module manufacturers to optimize design strategies. Additionally, the results of this project will enable deeper understanding of the reliability of backsheets and will reduce the uncertainty
# TOPCon solar modules show self-healing under UV stress – pv magazine Global Source: Blog/Web URL: https://www.pv-magazine.com/2026/03/10/topcon-solar-modules-show-uv-induced-degradation-recovery-study-finds/ Author: Emiliano Bellini Date: 2026-03-10 A group of researchers from China’s Nanchang University and solar module manufacturer Trina Solar have conducted a series of experiments to assess the impact of ultraviolet-induced degradation (UVID) on the performance of tunnel oxide passivating contact (TOPCon) solar modules and have found that this panel type can offer “metastable resilience” in real-world operation. “Our lab-to-field studies confirm that UVID in TOPCon is a light-recoverable metastable effect with no impact on real-world energy production,” the research’s lead author, Zhiwei Li, told pv magazine. “This is critical for improving investor confidence and bankability, and establishes a clear reliability understanding for the industry.” The researchers conducted UV accelerated aging tests on TOPCon solar cells using a HY-UV-4225 chamber equipped with a metal halide lamp emitting in the 280–400 nm range. During these experiments, the UV intensity was set to 180 W/m², and the module temperature was maintained at 60-65 C, with the samples being placed under short-circuit conditions in a chamber at 50-60 C and exposed to a cumulative irradiation dose of 2 kWh/m² from an 800 W/m² light source spanning 300–1200 nm. The cells were sandwiched between standard module glas
# Impacts of PicoPV and Consumer Research Source: Blog/Web URL: https://energypedia.info/wiki/Impacts_of_PicoPV_and_Consumer_Research Author: Date: 2018-08-01 Impacts of PicoPV and Consumer Research Overview As experience with other renewable technologies show, lack of social acceptance and incongruity with cultural values and norms are common barriers during the implementation phase. Therefore, it is important to investigate in users needs and behavior patterns. Additionally, experience shows that laboratory test have to be complemented with field tests in order to test the solar lanterns under real-life conditions. Due to the fact that many bad quality products exists, it is also important to test selected products in a field test. GIZ Energising Development has conducted various tests in different countries, such as Bangladesh, Bolivia, Ethiopia, Mozambique, Nicaragua, Peru, Senegal and Uganda. Approaches of these tests differ, results and outlook are presented within this articles. Performance of Solar Lamps More than 100 firms are offering PicoPV products in developing countries today, but most products are of very low quality, with serious implications for consumer trust in the new technology. Early lab tests have focused the awareness of governments and donors on the importance of quality control and customer information – however, field tests in sufficient countries with sufficient sample sizes are needed for a better understanding of PicoPV performance under real-lif
heat. – Temperature—Solar cells generally work best at low temperatures. Higher temperatures cause the semiconductor properties to shift, resulting in a slight increase in current, but a much larger decrease in voltage. Extreme increases in temperature can also damage the cell and other module materials, leading to shorter operating lifetimes. Since much of the sunlight shining on cells becomes heat, proper thermal management improves both efficiency and lifetime. – Reflection—A cell's efficiency can be increased by minimizing the amount of light reflected away from the cell's surface. For example, untreated silicon reflects more than 30% of incident light. Anti-reflection coatings and textured surfaces help decrease reflection. A high-efficiency cell will appear dark blue or black. Determining Conversion Efficiency Researchers measure the performance of a PV device to predict the power the cell will produce. Electrical power is the product of current and voltage. Current-voltage relationships measure the electrical characteristics of PV devices. If a certain "load" resistance is connected to the two terminals of a cell or module, the current and voltage being produced will adjust according to Ohm's law (the current through a conductor between two points is directly proportional to the potential difference across the two points). Efficiencies are obtained by exposing the cell to a constant, standard level of light while maintaining a constant cell temperature, and measuring t
materials in their glass, encapsulation, and diffusion barriers. All panels also suffer something called light-induced degradation (LID), in which panels lose efficiency within the first hours of being exposed to the sun. LID varies from panel to panel based on the quality of the crystalline silicon wafers, but usually results in a one-time, 1-3% loss in efficiency, said testing laboratory PVEL, PV Evolution Labs. Weathering The exposure to weather conditions is the main driver in panel degradation. Heat is a key factor in both real-time panel performance and degradation over time. Ambient heat negatively affects the performance and efficiency of electrical components, according to NREL. By checking the manufacturer’s data sheet, a panel’s temperature coefficient can be found, which will demonstrate the panel’s ability to perform in higher temperatures. The coefficient explains how much real-time efficiency is lost by each degree Celsius increase above the standard temperature of 25 degrees Celsius. For example, a temperature coefficient of -0.353% means that for every degree Celsius above 25, 0.353% of total production capability is lost. Heat exchange drives panel degradation through a process called thermal cycling. When it is warm, materials expand, and when the temperature lowers, they contract. This movement slowly causes microcracks to form in the panel over time, lowering output. In its annual Module Score Card study, PVEL analyzed 36 operational solar projects in Ind
performance limits. UNSW research has previously revealed atomic-scale self-repair mechanisms in silicon solar cells that can partially offset UV-induced damage, but these mechanisms may be insufficient to counteract the elevated UV doses delivered by tracking systems and high-irradiance locations to next-generation cell architectures over multi-decade operational periods. “One of the key messages from our paper is that the UV testing standards need to be amplified or changed,” Dr Poddar added. “With new high-efficiency PV technologies being rolled out so quickly, we need to ensure the standards reflect real-world conditions.” The researchers emphasise that the new modelling tool is designed to help manufacturers, developers and asset owners make better-informed decisions throughout the project lifecycle. UNSW believes that, before installation, developers could use the global UV map data to conduct more rigorous accelerated UV stress testing on candidate modules, selecting products that demonstrate resilience to the specific UV exposure profile of the deployment location and mounting configuration they intend to use.
cell panel light shade, bulb, battery components within the bulb (containing charging circuit and battery and a mounting member. – the purpose of said mounting member is for the fixture to be either directly buried in the ground, or provided at the top of a post, in a mechanical equipment, or to a vehicle including a automobile, a sea vessel or an aircraft. – Said member may be also provided in a form of an underground post or ground tapered support. – the light shade of the solar cell panel and the bulb are integrated that encourages heat to build up inside the bulb due to hyperthermal effect when the solar cell panel absorbs solar energy. Since the heat can not be effectively dissipated, the performance of the charging circuit and cell components is vulnerable to damage or failure. – the primary purpose of the present invention is to provide a solar cell lighting fixture integrated with a heat sink. – the prevent invention is for adaptation to a post lantern, a garden light, a wall fitting, or a vehicle including an automobile, a sea vessel or a aircraft, or a bicycle, a motorcycle, a portable light or other types of lighting fixtures. – a ventilation space is provided between utmost top and bulb of the lighting fixture of the present invention. – the utmost top of the lighting fixture accommodates an upper lid of a solar cell panel. – Battery components such as a secondary cell or a battery capacitor, and a charging circuit or device to convert electric energy into optical
# Preventing Electronic Corrosion in Solar Lights – Lighting Global Source: Blog/Web URL: https://www.lightingglobal.org/preventing-electronic-corrosion-in-solar-lights/ Author: Jen Date: 2013-09-27 Preventing Electronic Corrosion in Solar Lights Lighting Global has published the 14th issue of the Technical Briefing Notes titled “Protection from the Elements Part III: Corrosion of Electronics“. This is the third article in a four-part series examining the environmental durability of pico-powered lighting products. The article describes the chemical processes and environmental mechanisms of electronic corrosion in a solar lighting system, and provides steps manufacturers can take to increase the corrosion resistance of their products. It notes that most pico‐powered lighting products are exposed to intense sunlight and heat on a daily basis. They are also continually moved around because of their portability rendering them vulnerable to drops and spills. Furthermore, they get dirty from ground contact and rough handling, and many will be exposed to water in the form of rainfall, moisture in the air, and groundwater contact making their components vulnerable to corrosion. “The electronic nature of pico‐powered lighting products coupled with their typical service environment creates an atmosphere that can be very conducive to corrosion. The batteries, electronic circuit boards, LED lights, and multiple external connectors (for wires between product components) are all potentiall