The Double 85 Test is an environmental stress acceleration test typically conducted at a temperature of 85 ℃ and a humidity of 85% RH. This type of test is mainly used to evaluate the performance and stability of products in high temperature and high humidity environments. The testing time for the Double 85 test may vary depending on different products and testing requirements. Generally speaking, the testing time for the Double 85 test is 168 hours, but it may also be extended to 1000 hours or longer depending on specific circumstances.
The equivalent actual life calculation of the Double 85 test usually uses the Arrhenius model or Hallberg Peck model. These models can predict the lifespan of products based on testing conditions and actual usage conditions. For example, if a product operates at 25 ° C and 60% humidity with an activation energy of 0.67Ev, and the aging acceleration factor is calculated to be 202.2 using the Arrhenius formula and Peck model, then no failure occurs after 1000 hours of double 85 testing, which is equivalent to verifying that the product has been operating at 25 ° C and 60% humidity for 20 years.
The equivalent lifespan of the double 85 test time is a predictive indicator and cannot guarantee that the product will reach the predicted lifespan in actual use.
The acceleration factor calculation of the Double 85 test usually involves two types of stress: temperature and humidity. For example, if a product is used at room temperature and is planned to undergo accelerated life testing at 75 ° C and 85% RH, the acceleration factor can be calculated using the Arrhenius model and Hallberg Peck model. In this example, if the activation energy of the product is 0.6 eV and the room temperature is set to 25 ° C and 75% RH, the calculated acceleration factor is 37. Therefore, conducting a 1-hour test at 75 ° C and 85% RH is equivalent to a lifespan of approximately 37 hours at room temperature.
Another example is that if a product actually operates at 25 ° C and 60% humidity, its activation capacity is 0.67Ev. Using the Arrhenius formula and Peck model, the aging acceleration factor is determined to be 202.2. This means that testing at 85 ° C and 85% humidity for 1000 hours without failure is equivalent to verifying 1756276 hours of MTBF, which is approximately equivalent to each product working for 20 years at 25 ° C and 60% humidity.
In summary, the acceleration factor in the Double 85 test is usually calculated based on specific product characteristics and usage conditions, and there is no fixed value. In practical applications, it is necessary to determine the appropriate acceleration factor based on the specific situation of the product and testing objectives.
In practical operation, the calculation formula for the equivalent life of the double 85 test time usually uses the Arrhenius model, which has the basic form of:
T2=t1 × exp (Q/k × [(1/T2) − (1/T1)]), where:
T1 is the lifespan time in the actual usage environment;
T2 is the equivalent lifespan time under the double 85 test time;
Q is the activation energy of the sample;
K is the Boltzmann constant;
T1 is the temperature in the actual usage environment;
T2 is the temperature in the double 85 testing environment.
This formula is a theoretical model based on many assumptions and approximations, so the results are not entirely accurate. When using this formula for prediction, it is also necessary to know the temperature, humidity, and other parameters of the actual usage environment of the sample, and to correct the changes in these parameters. At the same time, it is necessary to make reasonable choices and adjustments to the parameters of the formula to achieve more accurate prediction results.
It should be noted that the double 85 test time equivalent lifespan is a predictive indicator and cannot guarantee that the product will reach the predicted lifespan in actual use. Therefore, only through continuous monitoring and testing in actual use can the lifespan of the product be truly determined.

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