Electronics in headlamps
Power electronics in our Lucifer lamps
We completely design and program the electronics in all our powerful headlamps. Designed with the ultra-high efficiency in mind and all modern features such as constant light control , discharge warnings and most intuitive user control. It contains carefully selected and dimensioned discrete SMD components (quality X7R ceramic capacitors, very low resistance n-mosfets, large shielded coil and precision thermistors and resistors), all controlled by an Atmel microprocessor and soldered on a copper printed circuit board. The switch is large, dimensioned for 500,000 presses and ensures that the headlamp catches your every press. All of these things contribute to maximum reliability and ease of use and extreme runtimes of our headlamps..
We manufacture electronics at two Czech companies that provide constant quality of materials and services. Then, before assembly, we first check that each electronics is functional. After assembly, each headlamp must pass several quality tests to verify that all functions work properly. So that we are sure that every headlamp shipped is fully working and meets our standard.
The base is a switched converter (buck or boost), which transforms the voltage to another voltage with high efficiency (typically 92-95%) and operates at a relatively low frequency. This means that the inverter is electromagnetically very quiet (it does not emit EMI to the surroundings) and acoustically completely silent - it emits no hum.
CONSTANT LIGHT BRIGHTNESS is a basic feature that ensures that the headlamp intensity is constant all time during discharging, regardless of battery state. If the battery is nearly fully discharged, the electronics will gradually switch to lower modes, in which it will shine for several hours. The light never shuts off suddenly.
The electronics also monitor the REMAINING BATTERY CAPACITY . It notifies you with one short flash when you have less than 33% charge, two flashes for less than 10%, and three flashes when the battery is completely discharged. The warning is not disturbing and repeats after 15-30 minutes if you miss the first warning. Thanks to this, you know exactly how much runtime you have and you can react in advance and reduce the mode.
One flash = less than 33% battery
Two flashes = less than 10% battery
The headlamp can easily tell you exact STATE OF BATTERY CHARGE. This function is activated by holding the button for a second or longer, the light turns on and then flashes 1-5 times. Each flash represents 20% of remaining battery charge. So, if the headlamp flashes 4 times, the battery is 80% charged.
State of charge signalization - 3 flashes = battery is charged approx. 60%
Why the powerful headlamp needs some kind of electronic circuit?
The answer is simple - every battery doesnt have one stable voltage, the voltage lowers down during discharge. When the battery is full, voltage is highest. When the battery is empty, voltage is the lowest. When considering li-ions, the voltage range is 2.5 to 4.2 volts. AA batteries have lowe voltage range 0.9-1.5 volts. When somebody would connect battery directly to LEDs, it wouldnt properly work. Either the voltage would be too high or too low. It would somekind work when adding resistance into the circuit, but even this approch doesnt work well enough.
LEDs, by their nature, must be driven by current, not voltage. Each produced LED has a slightly different voltage, and this also varies with the temperature. Therefore, one correct output voltage cannot be set. The electronics must control the light by monitoring the current flowing through it (usually on a sensing resistor), its the only reliable and correct method that provides a reliable repeatability and constant light brightness setting.
The electronics of a headlamp is a printed circuit board hidden inside the lamp , on which are copper paths and the components, LEDs and microswitches placed. The electronics consist of a driver and a converter . The converter transforms (increases or decreases) battery voltage to the LED voltage. The driver controls all switching, monitors the temperature, gives signals about battery discharge, etc.
Two basic converters
All converters can be divided to 2 groups:
- LINEAR CONVERTERS - easy, unefficient just for moderate power - all voltage higher than needed is burned and wasted
- SWITCHING CONVERTERS - complicated, voltage is converted with various circuit topologies, no energy is wasted, can be up to 95% efficient
Its clear that linear converters are really only for those simple, cheap and weak headlamps usually powered on AA batteries, which you take for camping. All proper headlamps must necessarily convert voltage so that they do not waste energy. The conversion efficiency can reach anywhere from 70 to 99%. 100% cannot be realistically achieved even with maximum effort. Absolutely top values are anything above 90%. Many current lights work with an efficiency of 75-85%. Achieving more than 90% is really challenging and not really easy! Reaching 95% or 97% is a record achievement and it will extend your runtimes by minutes, tenths of minutes to hours.
Of course, no company will tell the efficiency of their lights, there is usually nothing to celebrate. Efficiency can't be easily measured, you would need to disassemble the headlamp, understand the circuit and measure it.
PWM - pulse width modulation
PWM is just some high frequency of 10.000-100.000 Hz square wave. Some headlamps use this fast on/off signal to regulate its dimming. So fast blinking seems to any human like a continous light, let me say even the common lightbulb at your home blinks 60 times per second.
Such a method of regulation is also disadvantageous, it can annoy the user and you will recognize him in the night photos, where the light of the headlight does not draw one smooth snake, but rather more distinct points. In addition, it is ineffective, as half of the time the LEDs are driven on full and half time not driven. Much better is when the LEDs are still on, but at half intensity.
Constant Brightness Regulation
Constant brightness (current) regulation is a key function of today´s brightest LED headlamps. It ensures that the head torch shines with the same intensity from the beginning to the end, there is no decrease in brightness (current) during the discharge of the battery. There are many headlamps without constant regulation even today, these lights can be used, but if you use a headlamp often or you have higher requirements, it will limit and annoy you. However this is not a small issue - the difference in brightness during discharge can be really extreme - e.g. the headlamp shines well for a few minutes in the beginning, but then the light begins to drop rapidly to 1/20 of the original light.
More information about runtimes in this article: www.luciferlights.net/headlamp-runtimes
Electronics, failures and reliability
The more complex the electronics, the more failures can occur on them. Some of them can also cause headlamp malfunction and repair could be difficult. Reliability usually decreases even with higher lamp temperature. Therefore, the design requires a lot of knowledge, prototyping and testing. Just because something works in the lab doesn't mean it will work after 2 years of use.
You can be sure that every Lucifer headlamp we put on the market is proven and works properly. Nobody tells us exactly when a new model has to come out, so we work hard on new headlamps until they are perfect, tuned to the maximum, and only then we put them on sale. It also never happens that we cancel any popular model line, for example due to some marketing research or management decision. All these series of our headlights (S, M, L, X, Z1), which we once started to produce, we will produce permanently - we stand behind them, these model lines make sense and there are just enough of them.
Also know that if a problem occurs in the future, we are able to solve everything successfully and quickly, to your full satisfaction, because we designed the electronics ourselves and know it from A to Z. Now we provide a 3-year warranty on all headlamps and we can allow that, because over the years of development we have been able to reduce the number of defects to an absolute minimum. We don't make washing machines, microwaves, radios and headlamps together - we really specialize only in LED headlamps and we make them world-class!
We have been producing headlamps for 6 years and we are constantly increasing reliability and reducing the level of defects that may occur. We have practically reached the point where no defects actually occur on the headlamps during the warranty period.