if these mags are putting out 500-600 lumens otf with xml2 then its only being driven to about 1.4 amps at the led which is not much.
The
Cree data sheet for the XM-L2 lists 1500ma for 580 emitter lumens.
HKJ lists the discharge time for a D cell alkaline at 1 and 2 amps at between 9, and 2.5 hours respectively.
If the light is regulated, then the amperage draw will change over time as the batteries deplete, and the initial draw may be less because the voltage will be over 4.8 volts. And if I am reading the Cree datasheet correctly, the LED should not be driven above 3.3 volts.
Anyone want to venture a guess as to what the expected run-times would be? I certainly do not know.
My guess is that it would drop off significantly in the first hour, run pretty good for the next four, and then at about 40 lumens for hours... just a guess.
I did a run-time/calculated output test on a 3D lantern with a Cree XB-D emitter.
Initially the lantern pulled 700 ma high, and 390 ma low. ~210 lumens, and 130 lumens.
At the end of the first hour it was down to about 175 lumens
And at the end of the fifth hour it was just above 120 lumens.
For the seventh through seventeenth hours it was between 100 and 110 lumens.
Hours 18-28 it was between 80-95 lumens.
Hours 29-40 were between 70-80 lumens.
Hours 40-55 were between 40-63 Lumens.
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EDIT.. I see 117 hours run-times. !!!
Ouch, that's disappointing. I THINK that means that it is regulated, to dive from max output to 10% within the first hour, and then stay there for 116 hours. Unless the run-time they are advertising is for their low level of output.
Geeez I wish there was more standardization in advertising run times and actually using output graphs. Otherwise... how is one to know?