I just got the C Crane charger, it works well on those very same RS 4500 mA/H D cells. It is designed and rated for AAA, AA, C and D sized NiMH and NiCD cells. Not alkalines or lithiums.
I also have two of the Maha C777 chargers, have had them a couple years. Actually, one is a radio shack branded Maha. Same thing, different number. It handles 4 to 10 NiMH or NiCD cells in series (4.8 to 12V). I have also used it on low amperage Lead-Acid (2300 mA/H "bagphone" batteries and it seems to work. The Maha manual does not mention this, the RS manual does. I have
once tried Lithiums on the Maha, seemed to work, but I would not recommend this, too many chances
to cook or kill the Lithium or the charger.
C Crane has 9,000 mA/H D size NiMH, but I have not yet gotten any to try out. 6 in a 6D maglite
should make a 5W Luxeon do wonderful things, probably shoudl throw a low-ohm resistor on series so not to smoke the LED into a SED.
/ed brown in NH