Terralux TLE-310M-EX in a 4D Maglite

Any one have a idea of the actual OTF Lumens output of this combo when run with four 10,000 mAh NiMH D cell batteries? I know that the advertising CLAIMS 1000 Lumens for the TLE-310M-EX but the actual packaging says that this is the LED manufacturers rating which would be LED Lumens at a particular drive current and voltage and I have no idea if Terralux actually drives the LEDs that hard. My light does have a glass front lens fitted.

I would presume that the NiMH batteries possibly start off at a lower output than fresh Alkalines but they should hold output much better due to lower internal resistance allowing much less voltage droop at high current levels. Per Tenergy’s downloadable spec for their Premium D NiMH batteries they are rated for up to 10 amps continuous current which I find impressive.

Comparing it with other lights I estimate the actual OTF Lumens to be in the 500 to 700 range by badly calibrated eyeball.