Drivers were tested on XHP50.2 LED soldered to 20mm DTP KD board. The board was screwed tightly to massive aluminium heatsink. Two lab PSU’s were used as smaller one cannot provide more than 5A.
- unexpectedly high efficiency of H1-A driver on two lowest brightness settings is remarkable. It seems it is optimized for low current modes. It will provide extreme system efficiency when used with XHP50.2 or XHP70.2 LEDs. It very likely will fall into the range of 200 lm/W on lowest mode! The driver efficiency quickly sags under higher drive currents and higher boost ratios, though.
- lowest mode with 26 mA will output 27 lm and it will last nearly 90 hours of continuous operation using 3500mAh Li-Ion cells, assuming 200 lm/W system efficiency. Wow.
- any higher mode will fall into lowest mode under 3.1V and warns about low battery voltage with intermittent quick flashes. - low mode drains the battery until it falls below 2.6V where UVLO trips in.
- considerably better efficiency on turbo mode of XHP70.2 driver. Much worse on lowest mode.
- fifth ‘Turbo-boost mode’ with huge 4.5A current is activated using 2-click. Efficiency of this mode is low and power loss is huge.
- this driver will shut-up the light when input current approaches 10A on ‘turbo-boost mode’ what happens at 3.5V input voltage. Assuming internal resistance of the battery and series resistances of typical flashlight parts render this mode useless…
- both drivers hold their constant current drive levels very well, but H1-A driver is just outstanding in this regard! Its modes are nearly perfectly spaced.
I wish you will like it. More drivers tests to come!