www.batterieswholesale.com sells replacement packs for MagCharger and SL-20X. These lights use a single stack of 5 1/2D cells. The positive end of the SL-20X need not have much of a nipple, but the MC definitely needs a certain height protrusion in order to contact the mating spring at the switch core.
If you're just going for a NiCd replacement, the StreamLight or MagCharger stock packs are actually pretty good. They are 2.5 AH packs and will stand up to the 4 amp draw of the 1160 lamp just fine.
The Aero pack (
www.batterieswholesale.com) is a high quality, high rate capable, 3.8 AH NiMH pack that I highly recommend. Note that their webpage of 5 cell, 6.0 volt NiMH packs says that the pack is a 3.5 AH pack, but the last time people ordered any of these, they got a pack made from the 3.8 AH cells.
However, they are still not up and running, despite the fact that the webpage says that online ordering will be restored on "24 September". My friend CPF member Ginseng was actually doing testing of the 3.8 AH cells for Aero, and I called him to see if he had any inside information on what was going on--why there was no way to order, etc.--but I haven't heard back from him. I'll probably call him again sometime this week.
In any case, if there were enough interest, I believe that these Aero 3.8 AH cells are just the 3.8 AH cells available from
www.powerstream.com. And they can make up custom packs. There is a $200 minimum order, however. But still that would only mean about 5 or 6 packs, so it might not be that hard to scare up that amount of interest.
Or we could just wait for BWS.com to come back online.
As for a replacement NiCd pack that only costs $11, I suggest that it would be a good idea to have someone check one of these out, do some testing, etc., and report back. Good NiCd cells aren't cheap, and it does take some amount of labor and materials to make a pack out them, so we're talking like $1 1/2D NiCd cells. That scares me.