REDMI has shared a more detailed explanation of how it arrived at the 50,000-hour lifespan claim for the built-in cooling fan inside the REDMI K90 Max, its first smartphone with an integrated fan system.
The company said the figure refers to the micro fan staying stable for 50,000 hours at a test temperature of 40°C. Rather than literally running a single unit for more than five years before launch, REDMI said it used the industry-standard Arrhenius model for accelerated aging, combining higher test temperatures with a larger batch of samples to estimate long-term reliability.
According to the company, engineers tested 56 fan samples from the same production batch in a 70°C environment. After 2,484 hours of continuous operation, airflow, noise, and other key indicators were still in good condition. REDMI said that was stricter than a more common industry reference point of 1,360 hours under the same temperature and sample-count conditions, which it said roughly translates to 30,000 hours of continuous use at 40°C.
REDMI also answered a few practical questions about the cooling system. The fan supports manual switching, and the control entry points appear in several places, including the settings page, the pull-down control panel, and the in-game toolbox. Users can also trigger it by voice through Xiao Ai, though REDMI noted that it helps to say “phone cooling fan” clearly to avoid turning on other smart-home fans by mistake.
Once enabled, the fan offers three operating modes. There is a quiet mode for low-noise situations such as nighttime use, a high-speed cooling mode for gaming or heavier thermal loads, and an intelligent mode that adjusts fan speed based on current workload and device temperature.
The company also addressed questions about bypass charging. REDMI said the REDMI K90 Max still supports that feature in gaming scenarios, with power supplied directly to the motherboard so the battery generates less heat while users play and charge at the same time. The feature is enabled by default and automatically kicks in during gaming when battery level is above 40 percent. If users want to change it manually, REDMI said the setting has moved to Settings > Power saving and battery > Charging features > Smart charging.
Taken together, the explanation is clearly meant to reassure buyers that the built-in fan is not just a marketing gimmick. REDMI is positioning the test data, the multi-mode controls, and the continued support for bypass charging as part of a broader gaming-phone thermal strategy rather than a single headline spec.
