Electronics in Lucifer headlamps

We have completely designed and programmed the electronics in our headlamps ourselves. They are designed with ultra-high efficiency inverters and with all modern features such as constant lumen control, discharge signalling and convenient user control. They contain carefully selected and sized discrete SMD components (high quality X7R ceramic capacitors, ultra-low resistance n-mosfets, a large shielded inductor and precision thermistors and resistors), all controlled by an Atmel microprocessor and laid out on a copper PCB. The switch is large, rated for 500,000 squeezes, and ensures that the headlamp captures your every squeeze. All of these things contribute to the maximum reliability and comfort of use and extreme durability of our headlamps.

The electronics are manufactured and fitted by two Czech companies that provide consistent quality of material and service. We then first check each electronics to ensure it is functional before assembling. After wiring, each assembled headlamp must also pass several quality tests to verify that they all work properly. This ensures that we never send you a headlamp that doesn't work.

The basis is a switching converter (buck or boost) that changes voltage with high efficiency (typically 92-95%) and operates at a relatively low frequency of 128kHz. This means that the converter is electromagnetically silent (it does not radiate EMI into the environment) and acoustically completely silent - it makes no hum.

CONSTANT LIGHT CONTROL is an essential feature that ensures the headlamp shines in the set mode consistently, regardless of battery drain. At the same time, if the battery is nearing complete discharge, the electronics will gradually switch to lower modes in which it continues to shine for several hours. The light never goes out suddenly.

The electronics also monitors the RUNNING CAPACITY of the battery. It notifies you with one short flash when you have less than 33% remaining, two flashes for less than 10%, and three flashes when the battery is completely dead. The warning is not intrusive and repeats after 15-30mins if you missed the first warning. This lets you know exactly how much light time you have left and you can react in time to, for example, reduce the mode.

One flash = less than 33% battery remaining

Two flashes = less than 10% battery remaining

The headlamp can simply and quickly flash you the BATTERY CHARGE status. This function is turned on by long holding the button, the headlamp will light up dimly and then flash 1-5 times. Each blink represents 20% battery charge. So if the headlamp flashes 4 times, the battery is 80% charged. After that, the headlamp continues to shine with a weak light.

Charge status indication - 3 flashes = battery is approximately 60% charged

Why does a headlamp need to have electronics?

The reason is simple - any battery does not have one constant voltage, on the contrary it decreases during the discharge process. When the battery is charged, the voltage is at its highest. When the battery is discharged, it is lower. For example, for Li-ion it is in the range of 2.5-4.2V, for AA batteries 0.9V-1.5V. So if we connected the LED directly to the battery, it wouldn't work. Either the voltage would be too much for the LED (it would burn up) or too little (it would not light up). It would work to a limited extent by adding a resistor, but either way even that is far from ideal.

LEDs by their very nature need to be driven by current, not voltage. Each LED can and realistically does have a slightly different voltage, and this also varies with temperature. So you cannot reliably set one correct output voltage. The electronics must control the light based on monitoring the current passing through (usually at the sensing resistor), this is the only reliable and correct control method that provides a reliable repeatable and constant brightness setting.

The control electronics of the headlamp is a circuit board hidden inside the light, on which the components and the copper paths between them, and possibly the LEDs and microswitches themselves, are arranged. The electronics consist of an inverter and a driver. The inverter is responsible for changing (increasing or decreasing) the battery voltage to the LED voltage. The driver controls all switching, monitors temperature, gives signals about battery discharge, etc.

Basic 2 types of inverters

All electronics can be divided into 2 types:

• LINEAR CONVERTER - simple, inefficient and ineffective - all excess voltage is burned off for heat.
• SCORCHED CONVERTER - complicated, converts voltage to higher or lower, can have energy conversion efficiencies up to 98%

This shows that linear converters are really only for those ordinary weak headlamps usually on AA batteries that you take to campfires at most. All proper headlamps must necessarily convert voltage so that they don't waste energy. Conversion efficiency can range from 50-100%, but 100% cannot realistically be achieved even with best efforts. Absolutely peak values are above 90%. Many lights where not as much time is spent on design or where too much is saved on components operate at 75-85% efficiency. Achieving over 90% is very challenging indeed and it is certainly not automatic! Reaching 95% or 97% is then a record breaking feat that will extend the downtime by minutes, tens of minutes or even hours.

Of course, nobody will mention efficiency to you anywhere. You can't even simply measure it, for that you would need to disassemble the headlamp, understand the circuitry and measure it.

Flicker - PWM

Some headlamps use very fast flicker (e.g. 10000Hz = 10000 flickers per second) to reduce or regulate brightness. Such high flicker frequencies are usually imperceptible to humans (after all, even an ordinary light bulb flickers 60 times per second), so the headlamp appears to be on continuously.

This kind of control is also disadvantageous, can annoy the user and can be seen in night photos where the headlamp light does not draw one continuous snake, but rather multiple dots and lines. In addition, it is also inefficient as half the time the LEDs are on and half the time they are not - a much better situation is when the LEDs are still on but at half the intensity.

Constant brightness control

Constant brightness (current) control is a key feature of the headlamp. It ensures that the headlamp shines with the same intensity from the beginning to the end of the light, i.e. during the battery discharge (voltage reduction), the brightness (current) does not decrease at the same time. Headlamps without constant regulation are still available today and can be used, but if you use the headlamp frequently or have higher requirements, it will limit and annoy you. It is not a small thing - the difference in brightness during the discharge can be really extreme - the headlamp shines well for a few minutes at the beginning, but then the brightness starts to drop rapidly to 1/20 of the original brightness.

For more information, see the article on endurance: www.luciferlights.net/vydrz-na-baterie

Electronics, faults and reliability

The more complex the electronics are, the more faults can occur. Some of these can even cause the headlamp to malfunction and make repair complicated. Reliability usually decreases with higher temperature as well. Therefore, the design requires a lot of knowledge, prototyping and testing. Just because something works in the lab doesn't mean it will still work after 2 years.

With our Lucifer headlamps, you can count on everything we release to the market being tested and working properly. No one dictates exactly when a new model must come out, so we work hard on new headlamps until they are perfect, fine-tuned to the max, and only then do we release them for sale. Also, it never happens that we suddenly cancel one popular headlamp line because of, say, a marketing survey or a management decision. All of these lines of our headlamps (S,M,L,X,Z1) once we start producing will be produced permanently - we stand behind them, these model lines make sense and there are just enough of them.

Also, please know that if there is any problem in the future, we are usually able to resolve everything quickly and successfully, to your complete satisfaction, because we design the electronics ourselves and know them from A to Z. We now offer a 3 year warranty on all headlamps and we can afford to do this because we have managed to reduce the number of faults to an absolute minimum over the years of development. We don't make washing machines, microwaves, radios and headlamps together - we really only specialise in headlamps and make them to world class standards, see for yourself!

We have been making headlamps for 6 years and are constantly improving reliability and reducing the rate of faults that can occur. We have now virtually reached the point where there are really no defects on the headlamps within the warranty period. Even if, for example, a customer runs over the headlamp with a digger or drops it in a river.