You're absolutely certain it's driven under 1A? That's terrible. This should definitely be driven over 2A. What a waste.
Considering the dirty lens and scratch, you could make a case for a defective product considering <1A definitely isn't producing anywhere near the 850 advertised lumens.
Hi Pok, did you ever get to do the LED and driver upgrade to this light. From your tail-cap readings, I calculated about 2.23a input to the LED, then whatever the losses would be. I'm curious how much you were able to improve it.
Still extremely under driven and nowhere near the claimed output in lumens. I’m very surprised that the heatsinking is poor. In the photos on Ric’s page the heat sink looks positively beefy. For the money you payed for this light you shouldn’t have to invest another $15-$20 in a new emitter and driver to make it right.
Richie, how exactly do you perform your calulations? This uses a buck circuit, not a boost. I’m not sure how you generate additional energy than even the batteries are pushing on top of driver loss due to ineficiency to end up with 2.23A at the LED.
I figure around 1840mA (920mA x 2) to the driver, minus about 15% driver loss (assuming it's a decent driver, and I doubt it is) putting about 1.54A to the LEDs minus the additional losses by reflector and lens ending up with 500 lumen on it's luckiest day.
Richie, how exactly do you perform your calulations? This uses a buck circuit, not a boost. I figure around 1840mA (920mA x 2) to the driver, minus about 15% driver loss (assuming it’s a decent driver and I doubt it is) putting about 1.54A to the LEDs minus the additional losses by reflector and lens ending up with 500 lumen on it’s luckiest day.
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I missed the Buck circuit part.
I used the formula below:
.920mA * 8v = 7.36
7.36/3.3 = 2.23a
I also just noticed the pill is a drop-in on this light, not great.
Well the best way to measure efficiency, by the time you are going to swap a U2 led, is to cut the wire on the led and measure there the current that goes to the led with a multimeter, to be sure.
I also just noticed the pill is a drop-in on this light, not great.
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Nice, thanks for the info. I never take into account the additional voltage above what the LED uses when calculating. That would explain why you have more going into the LED than coming out of the battery.