17mm CC 2600mA LED Driver 2 Group Mode, 3-4.2v, 2.6A, XM-L





Driver is from lck-led.com

Official specifications

• Suitable for one 18650 or 26650 battery
• Input voltage: 3v-4.2volt
• Current and Modes: 2 Group / 5 level
• 1. High (2.6A) - Low (150mA) - Strobe - SOS
• 2. High (2.6A) - Low (150mA)
• With Mode Memory
• Constant current circuit
• Highly efficient
• Memory function
• Diameter: 17mm
• Total height: 6.25mm
• Gold plated contacts
• Low voltage protection: if below 3V, the light will step down to low mode and start flashing

Runing 5 seconds on Low mode the light will flash, then you can change group by turning off and on.



Measurements

Type: LD25, CHLD-25
Diameter: 15.8mm + 17mm
Height: 6.4mm
Driver is linear.
Driver has memory.
A short off/on selects next mode.
Driver uses linear regulation.
Driver has two mode groups:
Group 1: Low, medium, high
Group 2: Low, medium, high, strobe, sos
Strobe is 15Hz with 35% duty cycle.



High



Being a linear driver the led current and the input current is basically the same and the efficiency will be very high as long as the input voltage is at or below the leds Vf.
The driver drops to medium mode at about 3.3 volt and at about 2.85 volt it starts flashing a battery low warning.






Starting with a low voltage and increasing it, the driver does never leave battery warning mode.



Being a linear driver the output is very smooth.



The battery warning signal is fading off/on every 3. second.



Medium



In medium the led Vf is considerable lower and the driver stabilizes the brightes at a lower voltage..






Again the output is very smooth.



Low



In low mode the efficiency starts dropping very soon, due to the low Vf of the led.






And again a very smooth output.



Strobe



Strobe is 15Hz with 35% duty cycle.



SOS





Conclusion

This looks like a fairly well designed linear driver that is using a power transistor for regulation and not the usual 7135 chip.
It is necessary to be a bit careful when selection batteries, i.e. do not use batteries with 3.0 as minimum voltage, it is best to use batteries with 2.5 as minimum. This is not really a problem, because 2900/3100/3400mAh are all min. 2.5 volt batteries.



Notes

I am not very impressed with lck-led's custom service. I got one wrong driver and one driver that were far outside specifications. I have sent a couple of emails to them, I got one question back after two weeks: did I want money back or a new driver. There was no explanation if it covers one or both of the problems and I do not know if they have sent me a new driver (That was my answer).

How do I test a led driver
List of all tested drivers