👉 Which operating mode is the right one for my test?
This decision is crucial.
It not only influences the significance of the test results but, in the worst case, can determine the success or failure of the entire test.
Why is the operating mode so important?
Humidity-heat tests, such as cyclic humidity-heat testing with frost, simulate the impact of moisture and temperature changes on components.
This is particularly important for components that:
- Are exposed to temperature fluctuations
- Can absorb moisture through tiny cracks
- Are used in critical applications such as automotive or high-voltage technology
Each test has its own purpose and limitations.
VW 80000 – Operating Modes for Realistic Testing
Things get even more interesting when we look at VW 80000. This standard defines various operating modes to make tests as practical as possible:
🔹 Operation Min: Minimal load, e.g., in standby mode
🔹 Operation Max: Maximum load, e.g., under full power
🔹 Driving, Charging, Preconditioning: Additional modes depending on the usage scenario
These modes help replicate real-life stress in vehicle operation.
How do I find the right operating mode?
There is no universal solution—each case must be assessed individually.
🔎 Example 1: Control unit during driving operation
- Significant temperature rise due to engine heat
- Moisture could enter cracks
- Recommended test mode: Driving Max
🔎 Example 2: Sensor in a humid environment
- Sensitive to condensation
- Small temperature fluctuations lead to moisture absorption
- Recommended test mode: Operation Min with humidity exposure
The VW 80000 provides guidance but no definitive answers.
Ultimately, we must decide individually for each component.
Additional Factors Influencing the Choice
A small sensor reacts very differently to moisture than a massive power converter.
Therefore, we must also consider the physical properties of the component:
✅ Size and material – An aluminum housing behaves differently than a plastic cover
✅ Thermal properties – How quickly does the component heat up? How does it cool down?
✅ Failure mechanisms – Is there a risk of corrosion, short circuits, or delamination?
Choosing the operating mode is not just a formality—it determines the significance of the test.
Practical Example: Inverter for Electric Vehicles
An inverter is not only exposed to high temperatures during driving but also to strong vibrations.
👉 Logical test choice: Driving Max
But: Many inverters are regulated by cooling fluid.
👉 Extended test requirements:
- The temperature of the cooling fluid must be controlled
- Special test chambers with cooling circuits are necessary
These additional requirements make tests more complex but also more realistic.
Because: Only when test conditions reflect real-world use can the results be meaningful.
The Role of Documentation
Even though it is often dismissed as “paperwork,” thorough documentation is crucial.
According to IEC 60763-30, every test must be precisely documented:
📌 Test type and number of cycles
📌 Position of components in the climate chamber
📌 All deviations from the standard test
Only this way can we ensure that test results are traceable and reproducible.
Especially for safety-critical components such as high-voltage electronics, transparency is essential.
Conclusion:
🔹 Standards serve as a guideline but are not rigid rules—we must interpret them based on the situation.
🔹 Choosing the operating mode is a science in itself—it must consider the physical properties, thermal reactions, and failure mechanisms of the component.
🔹 Documentation is essential—it ensures transparency and comparability of tests.
Humidity-heat tests are far more than just a hurdle in development.
They are the key to durable, reliable, and safe products.
And that’s exactly why we take the time to plan them correctly. 💡
