Which products need to undergo alternating and humid heat tests in both high and low temperature test chambers simultaneously?

The core feature of products that require simultaneous high and low temperature alternation and wet heat testing is that they need to withstand the dual effects of "temperature periodic fluctuations" and "high humidity/temperature humidity alternation" in the actual usage environment - the two environmental stresses will work together. The following is a classification by application field, combined with specific product and scenario explanations:

1、 Outdoor electronic and communication equipment

This type of product is exposed to natural environments for a long time, and needs to cope with temperature fluctuations day and night/season, as well as withstand high humidity scenarios such as rainy days, plum rain, and morning dew. It is the core demand area for the "alternating+humid heat" test.

Typical products:

Communication base station equipment

Environmental characteristics: high temperature during the day, low temperature at night, and high humidity of 85% RH or above in rainy/foggy weather;

Test necessity: Temperature cycling may cause cracking of solder joints on the circuit board, and high humidity can exacerbate solder joint oxidation and insulation material leakage, which can easily cause communication interruption under dual effects.

Outdoor surveillance cameras, street light controllers

Environmental characteristics: temperature difference between day and night, high humidity during the rainy season, and some installations under tree shade/eaves may cause condensation due to temperature differences;

Test necessity: Temperature changes can cause deformation of the lens module, high humidity and condensation can cause internal circuit board short circuits and metal bracket corrosion.

Photovoltaic inverter, energy storage outdoor cabinet

Environmental characteristics: The photovoltaic panel area is mostly open-air, with high temperatures in summer and low temperatures in winter, and high humidity due to melting after rainy/snowy weather;

Test necessity: Temperature changes can affect the lifespan of electronic components such as capacitors and IGBTs, and high humidity can lead to a decrease in the internal insulation performance of inverters, and even pose a risk of fire.

2、 Automotive products

Cars will experience temperature fluctuations in different climate zones throughout their entire lifecycle, as well as wet scenarios such as rainy days, car washing, and air conditioning condensation, requiring dual verification.

Typical products:

Vehicle mounted radar and sensors

Environmental characteristics: Installed at the front/rear of the vehicle, with low temperatures in winter, high temperatures in summer, high humidity caused by splashing rain on rainy days, and even condensation due to temperature differences;

Test necessity: Temperature changes can cause phase shift of radar antennas, and high humidity can penetrate into the interior of the radar, leading to signal interference or circuit burnout.

car headlights

Environmental characteristics: When lit at night, the temperature inside the lamp can reach up to 80 ℃+. After parking, it cools down to ambient temperature. On rainy days, the inner wall of the lamp housing is prone to condensation due to temperature differences;

Test necessity: Temperature changes can cause thermal expansion and contraction of the lamp housing, aging of the sealant, and high humidity and condensation can cause the lamp beads to burn out and the reflective cup to rust.

New energy vehicle battery pack

Environmental characteristics: The battery heats up during charging, discharges in low-temperature environments, and the outer shell of the battery pack may come into contact with rainwater during charging on rainy days;

Test necessity: Temperature changes can affect battery capacity and cycle life. If high humidity penetrates into the interior of the battery, it can cause short circuits, bulges, and even fires in the battery cells.

3、 Aerospace and Rail Transit Equipment

This type of product requires reliability and needs to cope with temperature fluctuations and high humidity in enclosed/outdoor environments. The combination of these two stresses may cause fatal failures.

Typical products:

Aircraft onboard electronic equipment

Environmental characteristics: During high-altitude flight, the temperature outside the cabin is as low as -55 ℃, and when parked on the ground, the exposure temperature can reach 60 ℃+. Humidity fluctuations may occur when switching the cabin air conditioning system;

Test necessity: Temperature changes can cause deformation of the circuit board substrate, poor contact of connectors, and high humidity can exacerbate electrochemical corrosion of electronic components, affecting flight control accuracy.

Exterior components of high-speed trains/subways

Environmental characteristics: The temperature of the track in summer can reach 50 ℃+, and in winter it can be as low as -20 ℃. During rainy and snowy weather, the surface of the components may become damp and even wet with snow melting agents;

Test necessity: Temperature changes can cause aging of capacitors inside the inverter, and high humidity and salt residue can accelerate the corrosion of metal components, leading to short-circuit faults.

4、 Home appliances and consumer electronics

Although these products are mostly used indoors, some scenarios may face both temperature fluctuations and high humidity, requiring dual verification to avoid user complaints.

Typical products:

Washing machine, air conditioning outdoor unit

Environmental characteristics: When the washing machine is in use, the internal water temperature rises and then cools down after shutdown. The humid washing environment causes the internal humidity to remain above 80% RH for a long time. The outdoor unit of the air conditioner has high temperatures in summer, low temperatures in winter, and high humidity on rainy days;

Test necessity: Temperature changes can cause aging of washing machine seals, deformation of air conditioning compressor components, and high humidity can lead to internal circuit board leakage and metal component corrosion.

Portable consumer electronics

Environmental characteristics: During outdoor use, experiencing temperature differences between day and night, sweating, and high humidity caused by rainy days;

Test necessity: Temperature changes can affect battery life and screen display, and high humidity can penetrate into the interior of the device, causing button failure and motherboard corrosion.

5、 Medical devices

Medical devices need to balance "temperature fluctuations in different usage environments" and "high humidity residues after disinfection", and dual testing is the key to ensuring patient safety.

Typical products:

Portable electrocardiogram monitor, blood glucose meter

Environmental characteristics: Can be used in hospital wards, ambulances and other scenarios, and needs to be wiped and disinfected with alcohol after use;

Test necessity: Temperature changes can affect sensor accuracy, and high humidity can cause internal circuit insulation failure, leading to measurement errors.

Dental treatment equipment

Environmental characteristics: The equipment generates heat during treatment, high temperature and pressure are required for disinfection, and condensation occurs during the cooling process after disinfection;

Test necessity: Temperature changes can cause aging of equipment seals, and high humidity and high temperature can accelerate the corrosion of metal components, affecting treatment safety.

Summary: The core logic for determining whether a product requires double testing

As long as the actual usage scenario of the product meets both of the following conditions, high and low temperature alternating and humid heat tests need to be conducted simultaneously:

There are periodic temperature fluctuations;

There is a continuous high humidity or temperature humidity alternation.

In short, when the two environmental stresses of "temperature fluctuations" and "high humidity" jointly act on the product, a single alternating or wet heat test cannot fully expose potential faults, and reliability must be verified through dual testing.