Tag Archives: LED modules

Tero Explains: What is EPREL for light sources? 2/3

The first article of this 3-part blog post series was dealing with the near-term history of European directives and regulations related to energy efficiency and different energy-related products (ErP), not only energy-using products (EuP).

Starting from Kioto 2005, this process has then proceeded to the situation, where new kinds of regulations have been taken into use, concerning many energy-related products, the latest of those being light sources.

Since 1st September 2021, the insertion of light sources into the EPREL (European Product Registry for Energy Labelling) database has been possible officially. Some problems have occurred in the technical insertion process and also in decisions over which component is a light source and which component is not. The term ’light source’ is defined in the European Commission Regulation EU 2019/2020 laying down ecodesign requirements for light sources and separate control gears (Single Lighting Regulation, SLR).

In this blog post, you can learn how light sources are categorized and what this categorization means in each case.

Categorizing the light sources – is the light source removable or not?

I shortly presented the terms of ’containing product’, ’light source’, and ’separate control gear’ in my earlier blog post in this series. SLR requires that the light source and separate control gear are removable so that the luminaire/fixture can be called the containing product. If not removable, the whole fixture itself has to be regarded as a light source.

Here starts the categorization. I concentrate on light sources in this post. The easiest case is a containing product without a light source: Not Applicable (it is just an empty luminaire body that has no light source included). The second easiest case is the LED lamp that you can buy from a retail store. Then it is not containing a product but only a light source. The sales package in store should include an energy label and other information defined in SLR regulation. Additionally, the lamp information should be added to the EPREL database.

Then let’s proceed into the case(s) where containing product includes the light source.

The first question is that is the light source itself removable? If it is, then it has to fulfill light source requirements defined in Ecodesign/SLR regulation. It is enough that the light source is removable from the containing product without breaking the light source. The containing product is allowed to still deteriorate in that case, but not the light source.

Then there is the next case. If the light source is NOT removable without breaking it, then the whole lighting fixture is considered a light source. The sales package of the containing product has to include an energy label and also other information defined in SLR regulation.

So, the key point is the question, is the light source removable or not? The question, is the light source replaceable or not, is not relevant otherwise than for the end-user that is you or me, a consumer. The supplier (or manufacturer) has to inform in their technical representation, why the light source is not replaceable. This technical documentation should also include information that “this containing product includes a light source the energy efficiency class of which is X”. X can vary from A to G in the new energy efficiency classification. Light source information together with the energy efficiency class must be found in the EPREL database.

Requirements defined in SLR/Ecodesign Regulation

There are several requirements defined in SLR/Ecodesign regulation. These are:

  1. Energy efficiency requirements
  2. Functional requirements
  3. Information requirements (markings)

Energy efficiency requirements

First of all, energy efficiency requirements demand that power consumption of a light source can’t exceed Pon,max (W), which is defined for different light sources in the 2019/2020 SLR regulation. Pon,max depends on many parameters, some of them are real and measurable values and part of them are computational values or factors/multipliers. Computational values are based somewhat ”loosely” on the real world.

If you measure for example your LED board/module in the integrating sphere, and the light source is defined as a non-directional light source (NDLS), you can use all lumens that you measure in your sphere as useful luminous flux (term defined in SLR regulation). If you have a directional light source (DLS), the regulation defines which portion of light you can use for this directional light source. Usually, the measurement for the DLS light sources is better to carry out with a goniometer that can measure light intensity at different angles unlike with integrating sphere which collects all the light rays and integrates them for the spectrometer through an optical fiber.

This relates essentially to EPREL energy class information because you define the energy class according to the following equation:

hTM = (Fuse/Pon) x FTM

where hTM is total mains efficacy, Fuse and Pon are LED parameters (useful luminous flux and power consumption of the measured LED board, COB LED, or any other light source) that are measured from the light source and FTM is a multiplier that is 1.00 for mains light source (MLS, e.g. AC LED) and 0.926 for the non-mains light source (NMLS, e.g. LED board that needs a separate control gear for operation).

The updated measurement software can calculate hTM value directly when you first choose in the software, is your light source NDLS or DLS, and is it NMLS or MLS light source. So spectrometer first measures luminous flux and power consumption and calculates LED luminous efficacy, and then by using a correct multiplier for your light source, calculates total mains efficacy that defines the energy class. For example, in the case of an LED board with separate control gear, this multiplier is 0.926 (see the previous paragraph). Then you can add your LED light source to the EPREL database by filling in all public information, and the EPREL database creates the final energy label for your light source. For market surveillance, you have to add also other technical information, that is not publicly available for everyone.

Functional requirements

Then there are functional requirements. They include many parameters that also depend on the used control gear (LED driver in our case).

  • CRI index ≥80 (outdoor and industrial applications are the exceptions)
  • Power factor cosf (certain limits, depending on the control gear used)
  • Lumen maintenance factor (LED and OLED light sources) àbased on L70B50 value in hours
  • Survival factor (LED and OLED light sources) àrelated to the lumen maintenance factor
  • Color consistency (LED and OLED) àhas to be MacAdam 6-step or lower
  • Flicker PstLM (LED and OLED), depends on the control gear à PstLM≤1.0
  • Stroboscopic effect (LED and OLED), depending on the control gear à SVM value≤0.4

Two last values are defined at full load condition.

Information requirements (markings)

Finally, there are information (marking) requirements.

The surface of the light source itself (not package marking):

  • Useful luminous flux (lm)
  • CCT/Correlated color temperature (K)
  • For directional light sources (DLS), also radiation angle (°)
  • Depending on the size of the light source, the priority is 1) Luminous flux, 2) CCT and 3) radiation angle.

Packing information:

For all light sources, which are sold separately in an independent packaging (but not in a containing product) through a point-of-sale, there are several requirements regarding the packing information. Some of these are mentioned below. It is to be noted that the three first ones shall also be marked on the surface of the light source, given that there is space for all three.

  • Useful luminous flux (lm)
  • CCT/Correlated color temperature (K)
  • For directional light sources (DLS), radiation angle (°)
  • Electrical interface details
  • L70B50 lifetime (hours)
  • On-mode power (Pon)
  • Standby power (Psb)
  • Networked standby power (Pnet)
  • CRI/Colour rendering index
  • Indication if CRI<80 (note; the application must allow it)
  • Indication if the light source is designed for non-standard conditions
  • Warning sign, if dimming is not allowed or can be realized only with specific dimmers
  • Warning sign, if the light source contains mercury

As an alternative to text, the information can also be given in the form of graphs, drawings, or symbols. Besides this information, the packing must show the energy label.

If a light source is being sold as a part of containing the product (and the light source is removable), the requirements are different. In this case, there can’t be any energy label on the containing product packaging. The packaging must indicate the following:

  • Information on whether the light source is replaceable or not, must be shown on the packaging (in the case of end-user sales) or on a free-access website
  • Information if the light source can be replaced only by a professional

As an alternative to text, the information can also be given in the form of graphs, drawings, or symbols.

Conclusion

This is what SLR is in a nutshell. And how you define energy class for your light sources. For printing the label from the EPREL database, you can ask help from the EPREL help desk or your local officials.

In the third, and the last, article of this blog post series, we concentrate on the effects that these regulations may set for the whole lighting industry. As you can see, many parameters depend also on the driver/control gear that is used with the light source. How this affects the component (light source and/or control gear) selections to make genuinely Eco-designed containing products, this we will discuss in the last part of this series.

If you have any questions, you can email me at tero.nurmi@light.fi.


aLED Modules – high efficacy and quality

aLED LED nodules

aLED products are Arrant Light Oy’s own line of LED modules. 

We have been designing and producing LED modules since 2008. Our LED modules have been used for mass production luminaires and also for projects that need a special solution like in hospitals, automotive industry, safety light, and architectural lighting. We have dozens of standard LED modules at stock for instant deliveries. Also, we can quickly design and produce customized LED modules and prototypes for your needs.

We always use the best components for our LED modules, for example highly thermally conductive aluminum PCB and high reflective PCB solder mask. These features will make the LED modules and final product more efficient. We have chosen all components precisely and they fulfill our high-quality standards. 

We can produce LED modules exactly for your requirements.

  • Color rendering index (Ra80, Ra90, and Ra95)
  • Different color temperatures (1850K, 2200K, 2500K, 2700K, 3000K, 3500K, 4000K, 4500K, 5000K, 6500K and also special colors)
  • Tunable White and Dim-to-Warm
  • RGB and RGB-A
  • Different shapes of the module
  • Constant current and voltage

We Always Test our LED Modules

our integrated sphere

With our integrated sphere, we can measure LED modules and luminaires up to two meters in length. This way we can always get precise information about light quality and electrical features. In the production line, all our LED modules are already measured, but we still measure some modules of every production batch with integrated sphere. We want to be sure that current, voltage, lumens, efficacy, spectrum and color rendering index are what we promise. This way we can check that our products are uniform, high-quality and with the specs agreed.  

If you use our aLED modules, we can offer an additional measurement service for your luminaire’s photometric values. 

Below you can download datasheets about our linear LED modules. 

Tunable White – Achieve color temperature from 2700K to 6500K with one LED module

Tunable White color changing

The Tunable White is becoming a big trend in residential and office lighting. I introduced one color changing LED product, Dim-to-Warm LED, in the earlier post.  In this post, I will tell you about the Tunable White module. Its color temperature can be changed freely from 2700K to 6500K. This means that you can achieve warm light like incandescent lamp and daylight with only one module. In addition to changing the color temperature, you can also dim the brightness.

Why color changing and Tunable White is a trend? How does it impact humans?  Let me shed light on that.

As we know human mind reacts to brightness and temperature of light. Cool light (e.g., daylight) has a refreshing effect and helps us work at school, office, where ever effective work is needed. Where cool light refreshes, the warm light has a comforting and relaxing effect. Naturally, these lights are presented in daytime during sunrises and sunsets.

 

Tunable white color chart

 

How to use Tunable White?

With Tunable White module, you can create better environments for both working and living. You can maximize productivity and improve concentration. Here are just some examples of the usage, but really there are countless ways to use Tunable White. 

One great use for Tunable White is offices. You need a lot of concentration to work effectively. This can be achieved with decent lighting. With this module, as said before, you can control the cool and warm light and dim the brightness. This gives the opportunity to select the right color temperature for office during the daytime.

In residential usage, Tunable White gives a possibility to simulate circadian rhythm. Connect the Tunable White to a control unit, it can change the color temperature automatically by daytime. This way you can enjoy cold refreshing light by midday and get the comforting feeling of warm light by evening.

Now we know some examples, but what kind of luminaires Tunable White is suitable for? Tunable White module is very small sized. This gives options to use it in the wider range of luminaire types.

Here are some examples:

  • Downlight
  • Spotlight
  • Indirect lighting
  • Table light
  • Decorative light

How does it work?

Citizen Tunable White module is made by using “multi-chip” technology. That means it’s made of tiny LED chips that are combined into the same module. Because of its very small size (LCN-C01A is only 15×15 mm), smaller luminaires can be made than before. The small size also gives more even light. The spots between cool and warm dies are almost invisible, which guarantee more smoothly light.

It is made from cool (6500K) and warm (2700K) diodes. The color temperature changes by controlling the output of the two different colored LEDs. LED’s brightness depends on the current; reducing the current the brightness reduces. These features give the option to dim and change the color temperature of LED.

Color curve of Tunable White module.

The Tunable White module has linear color curve because it has two primaries (6500K and 2700K). Advantages of two primaries are greater efficacy and simplicity. As seen in the diagram above, the linear color curve is located under the Black Body Locus (B.B.L.). That affects the color of the light and brings some colors up. You can get white light without greenish tint. This improves contrast in other colors.

A suitable driver needs to have two channel outputs to control CCT and intensity of the light. So, you need 1-10V, DALI or another two-channel driver to control the Tunable White luminaire.

Our high-quality Moons S Series Intelligent Drivers have great compatibility with the Tunable White module. They also have deep dimming from 100 % even to 0,1 %. You can program correct tuning and dimming curves for your luminaire. With Moon’s drivers, you can get everything out of this LED module.

If you have anything to ask, please don’t hesitate to contact us. For more information please download the presentation and the datasheets link down below.

Download Here

Why Should You Choose the New aLED Module

We redesigned our aLED-modules based on customer and market feedback. Here is  a brief explanation on what is different compared to previous version. And why I think you should consider using aLED modules.

 

Figure 1. New aLED Modules with examples of different connector locations.

Better efficacy (159-191 lm/W)

We upgraded the SMD LEDs used in the modules to better suit our customers’ needs. aLED modules now have efficacy from 159 lm/W to 190 lm/W. Efficacy depends on the color temperature and you can see the efficacy by CCT here:

  • 2700K (174 lm/W)
  • 3000K (177 lm/W)
  • 4000K (185 lm/W)
  • 5000K (191 lm/W)

Better placement of LEDs

We have changed the design of our aLED module. LEDs are now placed on the center line of the module so the installation of optics is easier.

aLED modules dimensions have also changed. New modules are now either 279.2 mm or 558.4 mm in length and 20 mm or 40 mm in width. 

Different options for connectors

It is now possible to order aLED modules with connectors either on the frontside or on the backside. Traditionally the connectors have been on the frontside, but these new backside connectors allow you to hide the wires behind the module and inside the profile.

For longer luminaires, there is a possibility to use backline, so you won’t need long wires. Short wires to connect multiple modules together will be enough (figure 2).

Figure 2. a) How to connect modules without back line option. b) How to utilize the back line option of the aLED modules.

Long lifetime

Thanks to the upgraded LED, the lifetime of aLED modules has also increased. You can see the lifetime prediction below. But to be brief: at maximum TC temperature (85°C) the lifetime (L70B50) is over 100.000 hours (figure 3).

Fikure 3. The lifetime of aLED Module (L70B50)

Friendly to environment

On top of high efficacy and the possibility to save energy, aLED modules are also recyclable. You can recycle all parts of module, even the PCB.

In addition to all these changes aLED modules prices have also dropped to more competitive level.

You can find the technical details of 4000K modules from the table below. You can download the datasheets of these new modules by clicking here.

Product Code Color Temperature (CCT) Color Rendering (Ra) Luminous Flux (lm) Forward Current (mA) Voltage (V) Power (W) Efficacy (lm/W) Length (mm) Width (mm)
CALOSNU0405 4000 80 1182 600 11.6 7.0 170 279.2 20
CALOSNU0410 4000 80 1224 600 11.0 6.6 185 279.2 20
CALOLNU0805 4000 80 2363 600 23.2 13.9 170 558.4 20
CALOLNU0810 4000 80 2448 600 22.1 13.3 185 558.4 20
CALOLHU1610 4000 80 4895 600 44.1 26.5 185 558.4 40
CALOSND0405 4000 80 1182 600 11.6 7.0 170 279.2 20
CALOSND0410 4000 80 1224 600 11.0 6.6 185 279.2 20
CALOLND0805 4000 80 2363 600 23.2 13.9 170 558.4 20
CALOLND0810 4000 80 2448 600 22.1 13.3 185 558.4 20
CALOLHD1610 4000 80 4895 600 44.1 26.5 185 558.4 40

 

Download Datasheets

 

In addition to these new models, all our previous module models are also still available.

How to Connect LED Modules into AC Network

In my earlier post I went through the procedure of how to physically connect a single LED component into an AC network. The connection was made between COB LED and the LED driver. When connecting LED modules (LED diodes assembled on the PCB board) you do it pretty much the same way with slight differences.

Connecting an SMD LED module into the AC network

As with a COB LED component, you will need a suitable driver for your module (see: how to choose a constant current LED driver).  You connect the positive terminals and the negative terminals of the LED driver and the LED module together to create a closed electrical circuit.

The difference to connecting a single LED component is that you may have to connect several LED modules into the same LED driver. In such case, you have to use series connection. This means that you still have to create a closed electrical circuit formed by the LED driver and these LED modules on the secondary side. You arrange the primary side like you would with single LED components. On the secondary size you connect the positive terminal of the first LED module (leftmost module in Figure 1) into the positive terminal of the LED driver. Then you connect the negative terminal of the last module (rightmost module in Figure 1) to the negative terminal of the LED driver. See Figure 1 below that shows all connections between the components.

Figure 1. Connection of LED modules into AC network through the driver.

How do you make other connections? Series connection means that you always connect the negative terminal of the previous array to the positive terminal of the following array in the chain. See again Figure 1. The output voltage of your LED driver defines how many LED modules you can drive with one driver. In case of Figure 1, one LED driver drives three LED modules. If voltage over LED module is for example 12V, the output voltage of the LED driver should exceed 36V. In the real world, you have to take into account tolerances. So in this case, 40V can be used as target for the driver maximum output voltage.

In the same way, you can connect multiple COB LEDs in series. This may be the case when you need vast amount of light.

How to actually do it?

As for physical connections of SMD LED modules, there are four options:

  1. PCB terminal block connectors
  2. Soldering
  3. Wire-to-board connectors
  4. Board-to-board connectors

PCB terminal block connectors are quite popular. They are soldered on the PCB board in the reflow process (in reflow oven) after the assembly process. You push the wires into those PCB terminal blocks in the same way as you would push the wires into the push-in terminals of solderless connectors in the single COB case.

Figure 2. PCB terminal block connector (2-pole)

Soldering is an option, if there are separate soldering pads reserved on the PCB to solder the wire(s) with tin. Soldering is usually a more cost effective option.

The numbers 3 and 4 are the special cases when you wish to interconnect two modules with each other. I’ll skip them for now and save them for later post.

If you’re interested in aLED’s new, improved LED modules, read more over here.

Feel free to drop a comment if you have questions on this topic.

FAQ: aLED Modules

Q:You have the driving current 700mA written in the datasheet of your LED module.  Can I use smaller driving current?

A:Yes, you can use smaller current. The current value 700mA mentioned in the module’s data sheet is so-called nominal/typical value that corresponds to the value Citizen announces for voltage and luminous flux (lumens) of the diode used in that LED module.

The minimum current is defined by the diode datasheet and in our 700mA modules the minimum current is 70mA. But you can also use the larger current. The maximum current is 1190mA. Please notice that you have to take care of cooling of the module in case that you use the maximum current. The warmer the module, the lower the lumen output and the shorter the lifetime.

CALC-0814 Absolute Maximum Ratings Found From the Datasheet

CALC-0814 Absolute Maximum Ratings Found From the Datasheet

Q: What is the IP classification of your aLED modules?

A: It is basically IP00, because if our LED arrays are not placed inside the luminaire, they are subject to dust and moisture. So if you need IP classification for your luminaire, please ensure that the luminaire casing has the desired IP classification.

Q: Ok, your aLED modules are classified as IP00, can they then be potted or protected from dust or moisture with some special coating?

A: Basically if you want to cover them with some coating or even pot them, you have to always contact the supplier of that coating or potting material to find out how it affects the LED components. Usually LED manufacturer gives some warranty for their products but this warranty applies only under certain pre-specified constraints or conditions.

Additionally, using coating may alter, and probably does so, optics of the LED components from the characteristics announced in the datasheet of the LED component manufacturer.

So basically you can use potting or special coating, but you should always check how the process affects the module.

Q: How the driving current affects the lifetime of LED module?

A: The lifetime estimations curves, lifetime hours versus temperature TC, are informed for the LED modules at their maximum rated current. That means that maximum condition is used and then lifetime hours are announced at different TC temperatures. The TC point is found in every LED module and is usually located near the soldering terminal, anode or cathode, of the LED diode located near the center of the module.

CALC-0814 Lifetime Estimation curves

CALC-0814 Lifetime Estimation curves

Higher current means higher Tc point temperature and therefore it means shorter lifetime. On the other hand, lower driving current means lower Tc point temperature and therefore longer lifetime.

Q: Are your modules MacAdam 3-step compliant?

A: Our aLED modules follow color consistency in MacAdam 3-step. This means that from production batch to production batch color coordinate values stay within the MacAdam 3-step ellipse. This means that our modules are MacAdam 3-step compliant.

Depending on the CCT, variation in Kelvins is different for MacAdam 3-step, being ±65K for 2700K and ±140K for 4000K.

For 5000K and 6500K our LED modules are only within ANSI binning, not within MacAdam 3-step.

Q: How many aLED modules  you can drive with one 50W/90W 700mA driver?

A: It depends on the module, of course. For the sake of an example lets look at CALC0814-M17W1.

First of all, as you can see from the module’s datasheet, the power is 700mAx24.16V = 16.9W. This is power when the module is driven with 700mA typical current. If you use one 90W driver, you can drive 5 module in series connection.

Let’s do still check calculation. As given by the module’s datasheet, the maximum voltage of the module is 26.4V if all LED diodes are at maximum value of voltage binning range. This is unlikely, but should be checked anyway. Total voltage of 5 modules in series is 5×26.4V = 132V. In our example case the LED driver’s maximum output voltage is 129V. However, the case that all 40 diodes in series connection would have 3.3V (maximum voltage of voltage binning range) is very unlikely. With typical rated value of 3.02V given in the diode’s datasheet, total voltage of 5 modules in series is 40×3.02V = 120.8V, which is within driver’s output voltage range.

So 4 modules is definitely ok. Probably you could drive five, but then we would need to check that they all are from the typical binning.

If you use 50W driver, you can safely drive only 2 arrays in series connection. In our example case the LED driver’s maximum output voltage is 72V. If you drive 3 arrays in series, even the typical voltage is 3×24.16V = 72.48V, which is too much for the driver.

Q: How do you calculate aLED module’s total voltage and total current.

A: We use the information of the diode and the information how many diodes there are in series and how many in parallel.

Circuit Schematics for CALC0814

Circuit Schematics for CALC0814

Let’s take CALC0814-M17W1 as an example. Numbers ‘08’ and ‘14’ refer to electrical configuration of the diodes in the module. First number, ‘08’, refers to how many LED diodes are in series between the + and – terminal of the array.  Second number, ‘14’, refers to how many LED diodes are parallel in one LED chain. In this example, there are 8 pcs of LED chains in series and 14 LED diodes connected in parallel in each LED chain.

Typical value for the diode is 50mA and therefore there is 700mA going through each chain (14x50mA). That gives the total current of the module. With this typical current of 50mA, the diode forward voltage is 3.02mA and there are 8 LED chain in series in this module. This means the typical total voltage of the module is 24.16V (8×3.02V).

Q: aLED modules have quick connectors. Can I use soldered wires instead of quick connectors?

A: Yes, you can. If there are no separate solder pads for soldering wires, you can use quick connector solder pads but in this case the connector is not assembled in the assembly process. In some aLED modules both options are possible simultaneously.

Please note, that with different connectors, the delivery time might be little longer.

If you have some other questions, that were not found in this list, please feel free to ask me. I will answer to you directly and add the general questions to this FAQ later.

Tero Nurmi
Product Manager
aLED Modules
tero.nurmi@light.fi

How Lifetime Affects the Energy Savings of a Luminaire

Generally, when selecting LED luminaires, the attention is drawn to energy consumption. Efficacy, therefore, the power consumption, is the most important selection criterion. But do you pay attention to the lifetime of the luminaire? What happens if the better efficacy luminaire has shorter lifetime? This means that you may have to renew the luminaires much quicker. This adds expenses and eats off the savings from the electricity bill.

Lifetime of LED Light Source

Compared to traditional light sources, the lifetime of an LED light source is long. When a traditional incandescent bulb or a fluorescent tube runs out of its lifetime, it can’t be used anymore. It either won’t produce light or starts to flicker. LED only loses some of its brightness and is, at least in theory, eternal.

This is the reason why the lifetime of LED light sources is measured in a different fashion compared to the traditional. The lifetime of a traditional light source means literally lifetime. LED’s lifetime tells that at what point the amount of light drops below the desired value.

The terms for LED Lifetime:

  • L70, L80, LXX = How much of the original lumens are still available. For example L70 means that the light source still produces 70% of the original lumens. So if the light source produced 1000lm at the beginning, this has dropped to 700lm.
  • B50, B60, BXX = How many light sources are below the given lumen value. So e.g. B50 means that 50% of the light sources don’t produce the desired amount of lumens anymore.

Typically the lifetime is given as a combination of these two. For example L70B50: 60.000h means that after 60.000 operational hours 50% of the light sources still produces at least 70% of original lumens.

aLED Moduulin elinikäennuste

Lifetime estimate of aLED module

The lifetime can also be given using only the L-value. For example L70: 60.000h. Then the manufacturer doesn’t actually promise how many of the luminaires are still over 70% after 60.000h.

Taking Lifetime into Account When Selecting Luminaires

Let’s assume that you are lighting a space that has 1000 luminaires. For example a shop. You have narrowed your luminaire choices down to two: Option A and Option B. Currently the space has fluorescent lighting and more specifically 58W T8 luminaires, which produce roughly 4000 lumens each. Here are your options:

  • Option A
    • Luminous Flux :4000 lumens
    • Efficacy 150 lm/W
    • Power: 26.7 W
    • Lifetime L70B50: 50 000 hours
    • Price 120€/Luminaire
  • Option B
    • Luminous Flux :4000 lumens
    • Efficacy 130 lm/W
    • Power: 30.8 W
    • Lifetime L70B50: 90 000 hours
    • Price 120€/luminaire

It’s easy to choose option A. The power consumption is lower as the power is around 4 watts smaller. For example in your 1000 luminaire space this means 4kW and a significant savings in your electricity bill.

When you know the daily operational hours, you can calculate the annual electricity consumption and compare that to the old solution. For the sake of an example, let’s assume that your shop is open for 14 hours a day. When you add the time for cleaning etc., your daily operational hours are 16. At least in this example.

This way you get the following math:

  • Annual operational hours: 16h*365= 5840 h/year
  • Price of electricity: 0.1€/kWh
  • Traditional (58W Fluorescent)
    • Annual electricity consumption: 1000*58W*5840h=338720000Wh= 338720kWh
    • Electricity bill: 338720*0.1=33 872.00€
  • Option A:
    • Annual electricity consumption: 1000*26.7W*5840h=155928000Wh=155928kWh
    • Electricity bill: 155928*0.1= 15 592.80€
  • Option B
    • Annual electricity consumption: 1000*30.8W*5840h=179872000Wh=179872kWh
    • Electricity bill: 179872*0.1=17 987.20€

 

Both LED options drop the electricity bill down to half of the old solution, saving you a lot of money. Option A saves a little bit more, thanks to the better efficacy and lower power consumption.

In short term, option A would be the better solution. As it saves more per year. Option A saves annually around 2.4k€ more than Option B.

However, it is very rare that investment this size is made with a one, two or even five years scope. That’s why we should do the math for a longer period.

When we take the lifetime into account, the situation changes a little.

Let’s first calculate the lifetime in your application. When the daily operational hours are 16, the annual operational time is 5840h, as calculated above.

With this, we can transform the lifetime into a more understandable form:

  • Option A:
    • 50 000h/5840h=8.6 years
  • Option B:
    • 90 000h/5840h=15.4 years

So you would have to change the option A after 8 years while the option B can still light your space for 7 more years (15 in total).

When we look at the total savings caused by the luminaires, the numbers look like this:

Savings in electricity bill after luminaire change

Savings in electricity bill after luminaire change

Lifetime (a) Option A Option B
1  17 582.29 €  14 447.26 €
3  52 746.88 €  43 341.78 €
5  87 911.47 €  72 236.31 €
10  55 822.93 €  144 472.62 €
15  143 734.40 €  216 708.92 €
20  111 645.87 €  168 945.23 €

As you can see from the calculations and the chart above, the option A is better in the short term. But when you look for a long term savings, the option B’s longer lifetime kicks in before the investment reaches 10 years. You will have to replace the option A almost twice as often as option B.

So when you look at the investment in a long-term, the lifetime becomes very important.

When choosing luminaires, you should focus your attencion to both: efficacy and lifetime.  The more expensive the luminaire and the investment is, the more important the lifetime is.

How to select modules + driver package

In this blog post we concentrate on how to design a LED lighting package as a whole. And what different aspects you will have to take into account when selecting a light source and a driver.
I decided to write this as a case example so that the post is more concrete.

Most of the luminaire projects starts with the need for certain amount of lumen needed out from the luminaire. Then there can also be requirements for the shape and size for the light source. Color temperature, color rendering and lifetime expectancy might also be critical, but those are topics for a blog posts of their own.

LED Modules

LED Module

Case example

So in this case you have specified that the luminaire needs to achieve:

  • Lumen output 2000lm
  • Color Temperature 4000K
  • Ra(min)80
  • Lifetime 50 000 hours (LM70 for the whole luminaire)
  • Efficacy >120lm/W
  • Linear light source. Max length of 120cm

With these specifications, the finding of the suitable solution shouldn’t be a problem.
There are, however few things that have to be taken into account when looking at the data of LED modules:

  1. Lumen output: Some of the lumens from the light source will be lost due to the optics. The amount of lost lumens is around 10%. Therefore, you should look for light sources that can give you at least 10% more lumens than you need.
  2. The shape of the light source. Do you have a minimum size for the light emitting surface? The luminaire in this example can be built with modules around 30cm in length, but that would probably not be perfect fit your luminaire. It would leave a lot of empty space and the light distribution wouldn’t be even.

With those two in mind, you would need a light source that gives you roughly 2200lm and fills the whole 120cm evenly. That could be reached with for example 4 modules with lumen output of 550lm and length of 30cm or with two modules with 1000lm output and length of 60cm.

Selection of LED Drivers

Selection of LED Drivers

The Driver

For the case study presented above, you still have one more step to go: choosing a LED driver. Esko already wrote a good guide on this, so I’m going to be brief.

Before we can start, you have to specify one thing: How many LED modules do you want to drive with one LED driver? Only one module or several modules in series?

In this example you would probably want to drive all the modules with just one driver. This might be the case with all luminaires. In more complex lighting systems you might use several drivers. To find a suitable driver you will need to:

  1. Check the current that you want to drive your light source(or sources) with.
  2. Check the voltage of your light source (or sources) and check that it fits the driver’s voltage range.

You should always leave some room for the voltage as there might be some variations in the diodes. Check that the driver has around 10% lower minimum voltage and 10% higher maximum voltage than your light source.

So there you have it in brief. If you need more help or would like to leave a comment, please leave a comment or contact me!

You can also use our free tool to build your luminaire.

How to affect the lifetime of a LED module

How to affect the lifetime of a LED module

Lifetime of a LED module? What it means? Does it mean that LED module does not function anymore after the defined lifetime value? How to determine lifetime for the LED module? This post tries to explain what different lifetime estimation curves mean and how to interpret them.

Few terms have to be defined so that we can understand the lifetime for a LED module. First of all, the LED component itself, a tiny or a little bit bigger one, defines the lifetime of a LED module. Usually in normal conditions, all the other components last longer than the LED.

Some of the key parameters to evaluate LED module lifetime are listed below:

  • TC temperature = the temperature that can be measured from the LED module’s TC

This is usually placed so that it is as near to one of the diodes in the center part of the module as possible. This means as near LED component’s soldering pad on the PCB as possible.

LED Module, the point in the middle with the marking "TC" is the TC-point

LED Module, the point in the middle with the marking “TC” is the point where you measure the TC-temperature.

  • TJ temperature = the temperature of the PN-junction inside the LED diode.

This usually can’t be measured, but it can be calculated when the LED diode’s thermal resistance and the LED’s power consumption are known.

  • RTH = thermal resistance mentioned earlier. TJ = TC + RTH*PD, where PD is the power consumption of the LED diode.

Thermal resistance describes how well heat is transported out of the diode junction to soldering pad on the PCB. The smaller the thermal resistance value is, the better heat is transported away from the diode’s PN-junction.

  • LM or L = Lumen Maintenance.

LM value tells that how many percents of luminous output is still left from the original.

  • L80Bxx – the lumen maintenance lifetime

Bxx is a value at which xx% (e.g. 50%) of the products lumen output falls below 80% of the nominal initial value. If xx% is 50%, then it is expressed L80B50.

  • L80Fxx – the electrical failure time

Fxx is the value at which yy% (e.g. 10%) of the light source population has experienced conventional lights-out failure. If xx% is 10%, then 10% have experienced the catastrophic LED failure, other 90% of the LEDs continue lighting but at reduced lumen output level, was it then below or above 80% of the nominal initial value.

NB: It is very important to look at LED manufacturers’ lifetime estimates as some give the estimates as B values (for example B50) and some give the estimate as F values (for example F50).

Lifetime prediction for aLED Module at 700mA

Lifetime prediction for aLED Module at 700mA

How to design the LED module to have certain lumen output after certain operation time

There are few aspects that you should take into account when you want that your LED module operates more than expected operation time at the light output level that you, your customer or target application determines. If you for example require that after 50 000 operation hours of your LED module lumen output should be around 80% of the original lumen output value, you should consult your LED supplier. They will inform you the maximum TC temperature allowed for your LED component that this target will be reached. Or if your LED supplier gives lumen output curves versus operation time for certain TJ values, you should use the formula given earlier in the text to find out corresponding TC temperature.

When you find out the maximum TC temperature, there might still be some cases that you don’t reach the target lifetime. Then you should take some actions.

In the following there are some actions that you should think about if target hours are not reached:

  • Try using PCB with better heat conductivity.

Which PCB you have used? Is its thermal conductivity good enough to transport heat away from LED components that affect lifetime of the whole module? If you have used FR-4, why not to change it to Aluminum PCB.

  • Try adding larger heat sink or some other heat conducting elements.

Do you have effective heat sink under the PCB to conduct heat away from the PCB itself, not only from the LED components? Is there good thermal path from PCB to heat sink and have you used for example thermally conductive paste or tape?

  • Is there a way you could transfer the heat out from the inside of the luminaire?

Is your luminaire closed? Is there any way to transport heat away from the inner parts of the luminaire?

  • Think about separating light source and the power source.

The power supply also creates heat. Especially, if the luminaire is closed. Then it forms a closed system with two heat generating elements, the LED module and the LED driver. They both share the same heat load inside the luminaire, thus affecting each other.

Is there any means to divide the light source and the power supply, so that they are not in close contact with each other? Many times, if there is some kind of a metal profile into which the LED module is attached, the LED driver can be placed on the other side of the profile in order to avoid direct heat transfer between these two elements.

  • Can you leverage existing cooling solutions.

Ambient temperature(TA), affects the heat management of the luminaire.  Especially, if the luminaire is designed for application in some larger building, it can be possible to use for example building’s air conditioning system, to transfer heat away from the luminaire.

  • Can you change the driving current?

Of course, if you think the LED module itself as a single element and not as a part of a luminaire, also the driving current matters. Could you meet your lumen output requirements with smaller current during first years of operation? And when your light source’s lumen output starts to decrease in the course of years, is there a way to increase the driving current a little bit to reach the needed lumen output level after certain number of operating hours.

A table from aLED modules' datasheet. The typical current is 700mA, but you can drive it with as much as 1190mA. You can also drive it with much lower to save its lifetime.

A table from aLED modules’ datasheet. The typical current is 700mA, but you can drive it with as much as 1190mA. You can also drive it with much lower current (minimum in this case 70mA) to make its lifetime longer.

Those actions are some examples that you should consider to give your LED module required operation hours at certain lumen output level. Of course you should take the “big picture” into account: which kind of luminaire structure you have, which kind of driver you use and which kind of environment your luminaire is placed in.

Proper heat conduction and management are essential for long lifetime of your LED module! LED does not like heat.

If you have any comments or questions, you can post them in the comments.

What is aLED?

We released a new brand for our products; aLED. At first this brand is used along with our led modules, but later there will be more products to be labelled aLED.

There might be some people, possibly you, wondering what does aLED stand for? And why did we decide to create such a brand? Let me tell you.

aLED was formed during the spring and summer of 2014. There were many reasons behind the decision to create the brand and in this post I’m going open up those reasons.

Logo for the new aLED brand

Logo for the new aLED brand

  1. Warranty

We wanted to be able to give our customers a clear warranty. There can be many parties in the manufacturing process of a LED module. There is the PCB manufacturer, LED manufacturer, connector manufacturer etc. And all they give a different warranties and different conditions for those warranties. We wanted to give our customers a straightforward warranty:

aLED Module will last for at least 5 years. If it breaks while being used in a proper way before that, we will make it up to you.

  1. Delivery time

We got tired of the fact that the estimation of the delivery time for LED modules is guessing at best. PCBs are coming on one day, LEDs at another day and connectors on another. The company manufacturing the actual modules has time for production two months from now. We, and more importantly, our customers can never know when they get their products. We wanted to make this clear:

aLED Modules will be shipped in 48 hours after the purchase order.

aLED Module

aLED Module

  1. Variations in chromaticity

Our customers want to have guarantees that the module they order is actually near the right nominal color temperature. We have had these issues before and we know that everyone has had these issues. With the quality of the LEDs we use we can now guarantee the minimal variations in chromaticity.  So when you order your first module, all the following modules will have very little variation in chromaticity. To get an LED to exactly to a certain color temperature is near impossible, but we are working towards this.

  1. Right components

To be able to guarantee the quality of a LED module, all the components must be top quality. The modules are as good as the weakest link. We have taken a lot of time and effort to find the best possible components: the best PCBs, the best connectors, the best LED components and the best place to manufacture those modules.

  1. Customization possibilities

We know that our customers are different. For some the standard modules will be good enough and they can stand out with their luminaire design, price or some other factors. For some customers, the shape and type of the module is THE THING. That is the reason that we can offer customized modules to you. If you need soldered wires instead of connectors: you can have them. If you need customize shape with certain light distribution: you can have it. If you need anything else: you can have it. Delivery time might be a bit longer, but all the other guarantees still stand even for a customized module.

LED Module, which can be used in luminaire needing good light distribution.

Square shaped aLED Module.

  1. Best price

Everyone wants the perfect product for a perfect price. That’s what we have been aiming for. We have optimized the supply chain and negotiated good deals with component manufacturers. That is the reason we can offer you the best possible price.

These all might sound obvious, but they are not. We know that there has been problems and we have even had those problems ourselves. That is the main reason behind the aLED brand. We want to give you, our customers, a certain level of guarantee. We want to make the selection of LED module as safe and easy as possible.