ML and DML, Strength Training for Your Solar Panels

Home Blog ML and DML, Strength Training for Your Solar Panels

Solar panels need to be tough to survive 25 years of brutal weather on your roof.

If your roof tiles are expected to last for a lifetime, we want the solar panels to last as long as they can to reduce the LCOE of energy production.

But not all solar panels on the market are created tough.

WINAICO solar panels with an industry-leading, 25-year product warranty are designed to be resilient through rigorous reliability testing and optimised factory production.

The reliability tests that directly contribute to the panel toughness are Mechanical Loading (ML) and Dynamic Mechanical Loading (DML) tests.

We will share with you the differences between the two mechanical loading tests and what measurements you should expect from WINAICO solar modules.

What Is ML?

ML stands for Mechanical Loading test, it is where a solar module mounted on standard racking experiences a massive weight pressing down evenly on one side.

ml mechanical load solar module iec
Water can be used to establish constant pressure on both the front and rear of the solar panel for ML.

Common IEC 61215 standard tests require ML to be executed on both the front (5400 Pa test load) and the rear (2400 Pa test load).

This would equate to around 1000 kg weight on the front side and 450 kg on the back.

We would measure the power outputs before and after ML tests to make sure the modules only degrade in power by a small amount.

Despite the capability to withstand 1000 kg on the front side for a few hours, based on IEC standards, we still recommend handling solar panels with care and avoid standing on modules to prevent microcracks.

We Use ML Tests to Verify Clamping Zones

The ML tests can be used to confirm the range of clamping zones on our solar modules.

This is a good way to look for weaknesses in our module structure, and optimise the design through repeated testing.

winaico solar panel clamping zones
All the clamping zones of our solar panels are ML tested to ensure reliability.

By performing the right ML tests across different installation methods and at different mounting locations, we can outline the best clamping zones for our solar panels that give the best long term reliability.

What Is DML?

DML stands for Dynamic Mechanical Load test, it is an experiment that uses around 48 suction pumps to push and pull on a solar module for multiple cycles.

solar panel dml
DML test equipment to alternate up and down pressure of 1000 Pa.

Despite the IEC standard not making DML a compulsory test, WINAICO executes DML tests on our key products to make sure our solar panels can survive the harshest of environments.

DML Tests for Fluctuating Pressure Such as Wind

WINAICO implements DML as a quality check for product reliability against strong winds.

The Beaufort scale is a measure of wind force by categorising strong wind by an estimated wind speed.

The common scale goes from a level 1 light breeze to a level 12 hurricane, while only southeastern Asian countries have an extended scale that goes beyond level 12.

beaufort wind scale
The Beaufort scale that measures the wind level by wind speed. By Ldecola - Own work, CC BY-SA 4.0.

The 1000 Pa dynamic pressure converts to around 145.5 km/h (40.4 m/s) wind speed, which is a level 13 hurricane on the Beaufort scale, according to the extended scale used by Taiwan’s weather service.

So WINAICO’s solar panels are designed to be tough and resilient against the worst weather conditions your home can experience during the PV system’s lifetime.

To learn more about how WINAICO solar technologies can help with your rooftop energy production, please get in touch with us.

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