LED strips are more and more popular and are an excellent choice for commercial, residential, and industrial lighting. One of the main reasons is the very long life of LED strip lights. But how long do they actually last? How is lifespan defined? If you’re in doubt, read on to learn how and when your LED strips may fail and how manufacturers come up with their lifespan claims.
The structure of the LED strip
The main components of LED strips are LEDs, FPCB(Flexible Printed Circuit Boards), resistors or other components. LED strips are manufactured by using a process called Surface Mount Technology (SMT) Assembly Process to mount LEDs, resistors and other components onto the FPCB.
Some outdoor or underwater LED strips will be wrapped with silicone or PU glue.
Please note that LED strips with high IP ratings will have a shorter lifetime than IP20 led strips because high IP ratings led strip cannot dissipate the heat faster. In general, the cooler the environment, the higher an LED’s light output will be. Higher temperatures generally reduce light output. Please check here, How are LEDs affected by heat?
The most critical component of the LED strip is the SMD LED. The life of the SMD LED essentially determines the life of the LED strip. Then, how to calculate the lifetime of LEDs?
LED lifetime and the 70% rule (L70)
Unlike incandescent bulbs that burn out and fluorescent bulbs that start to flicker, LEDs behave differently over time, slowly and gradually losing light output. So unless there is a “catastrophic” failure caused by a power surge or mechanical damage, you can expect the LEDs on your LED strip to work until they are deemed too dim to use.
But what does “too dim to use” mean? Well, different lighting applications have different answers. However, the industry has somewhat arbitrarily decided that a 30% loss of light, or the remaining 70% of light, should be the standard. This is often referred to as the L70 metric and is defined as how many hours it takes for an LED to reduce to 70% of its original light output.
Sometimes, you can see the symbol LxByCz (h) describe the lifetime of LED.
It means the number of hours after which, from a group of LED luminaires:
• the luminous flux has dropped to x (%),
• y (%) of luminaires in the same group have dropped below the specified luminous flux,
• z (%) of luminaires in the same group have experienced total LED failure
Example: L70B10C0.1 (50,000 h)
• after 50,000 hours, the group of LED luminaires in question must still provide
• at least 70% of the initial luminous flux,
• whereby 10% of the luminaires are permitted to provide less than 70% of the initial luminous flux,
• and in 0.1% of the luminaires, all LEDs may have failed.
How is L70 calculated?
Since the choice of LED material varies widely between different types and manufacturers, a test method called LM-80 was developed to specify the primary standard for light lifetime testing. LM80 specifies that the sample is tested at a predetermined temperature and driving current. The time interval for measuring the light output change is 1000 hours, up to a maximum of 10000 hours.
LM-80 testing is usually performed at a third-party laboratory to ensure objective results, and the results are published in a report format. All reputable manufacturers perform this test for their LED lamps, and reputable LED strip suppliers should all be able to provide LM80 test reports, especially if you are buying in large quantities.
The difficulty with LED life testing is that it takes a long time. Even if the led lights are on 24/7, a 10,000 hour test takes about 14 months. This is an eternity for fast-moving industries such as LED lighting. Testing a product for the complete 50,000 hour requirement, in turn, requires nearly six years of continuous testing.
For this purpose, the TM-21 extrapolation algorithm is proposed. This algorithm considers the performance of the LM80 sample for the first few thousand hours and outputs an estimated lifetime.
TM-21-11 report: Projecting long term lumen maintenance of LED light source
Please check the full LM80 test report here.
LM80 test reports generally give the lifetime of L70. However, sometimes we need to know the lifetime of L80 or L90. Don’t worry, and I have prepared an excel tool for you. This tool can convert L70 lifetime to L80 or L90 lifetime. Please click here to download it.
1. FPCB(Flexible Printed Circuit Board)
High-quality, 2-4 oz double-layer pure copper flexible PCBs ensure the smooth passage of significant current, reduce heat generation and help the heat to dissipate more quickly. Heat can affect shortening the life of LEDs, so we need to find ways to dissipate it. By attaching the LED strip to the aluminum profile, we can dissipate as much heat as possible and reduce the working temperature.
2. Double-sided Tape
At LEDYi, we use 3M brand VHB tape. But, many suppliers offer no-name or, worse, fake brand name adhesives. The key to a long-lasting installation and thermal conductivity is a great quality tape.
The resistors are used to regulate the forward current through the LEDs so that the LEDs operate at the designed brightness. The value of the resistor may change from batch to batch. Use a reputable company for resistors.
Please ensure that you use high-quality resistors. Low-quality resistors may shorten the life of the LED strip or even damage it.
Do not overpower your LEDs! They will appear brighter at first but will fail fast. We know a few of our competitors that do this. The excess heat may also be dangerous if installed on flammable materials.
4. Power Supply
The power supply is also a crucial part. You must make sure to use a brand-name, quality-assured power supply. A bad quality power supply may output an unstable voltage that may be higher than the working voltage of the LED strip, thus burning the LED strip.
And make sure that the power of the LED strip does not exceed the rated maximum capacity of the power supply. To ensure that the voltage can work more stable for a more extended period, we generally recommend that the power of the LED strip should not exceed 80% of the rated maximum capacity of the power supply.
5. Heat Dissipation
The heat will significantly shorten the lifetime of the LED. So when we use LED strips, we have to find a way to dissipate the heat in time. Try to install the LED strip in a well-ventilated place. The LED strip sticks to the aluminum profile if the budget allows it. Aluminum is an excellent heat dissipation metal that can be timely LED strip heat dissipation out to extend the life of the LED strip.
The lifetime of LED strips can generally reach 50,000 hours. But, the quality of raw materials such as LEDs, FPCBs, resistors, the management of the heat radiated, and the power supply quality will affect the LED strip’s actual lifetime.