Try it with some NiCD or NiMH batteries to confirm that it is a current problem; the rechargeables are able to deliver more current than alkaline batteries. More likely though, is that there is a lot of internal resistance in the light, or the modification introduced a connection that is offering a lot of resistance.
I experienced a similar problem with a 4D Streamlight from the early 80's. The Mag LED bulb is a straight drop-in for that light, but the output was rather dim. When I replaced the Mag LED with a conventional 4 cell halogen bulb (with fresh alkalines,) the output from the incandescent bulb was also rather dim, so my conclusion was that the contacts had oxidized over the 25 years or so that the light has sat around in the harsh environments that it had been exposed to.
mbirds said:
I slightly modified a 4xAA dive light to accept a 4 cell Magled. The output is disappointing... seems to be about 20 lumens when I first turn it on (rough estimate.) Is it possible the AA cells have too much resistance, and the Magled really only should be used with C or D as stated on the packaging?
