Short time ago, I made a test to check - what is approximate capacity of a single or dual EN-EL3E battery capacity (in taken images, before imaging totally stops). Basic test setup was following:
-300/4.5 lens (at max aperture)
-raw images used
-menu: high ISO NR, off
-menu: long exposure NR, off
-"M" mode used
-bulb exposure selected
-camera at room temp, approx +23C
-MC36 trigger used
-exposure 60sec (1min)
-interval 62 (1min 2 sec)
-no limit in image count
It is not fully same, as camera used in low temperatures, like -20C. I would estimate, that in the cold environment - maybe 50...70% of this coud be achieved.
D200 Used with single EN-EL3E (without MB-D200) -> best result 49 images.
D200 Used with two EN-EL3E (with MB-D200) -> best result 91 images.