Icey,
The Welch Allyn bulbs I'm referring to are all T2.25-sized bare pin bulbs. They are slightly smaller than the Carley T2.5 bare pin bulbs like the 808 and 809. Being bare pins, they need to be either 1) stuck in a Carley #912 pin-PR base adapter (which is ok for up to 1.2A continuous and 2A intermittent use) or 2) potted in a ceramic-filled PR base by Carley. The ceramic potting is easily good for the 3.15A+ bulbs like the 01185. So, the sequence of events is 1) order bulbs from WA and 2) send them out to Carley for potting.
The 808 will run on 4x123 as will the 809. But since the 809 has a slightly higher operating voltage, it can run on 4.5 (4SF123+1AA lith). The WA 01318 and 01185 are 9.6V bulbs which run ok on 4x, nicely on 4.5x and dangerously on 5x. They will also do well on 9xAA nimh and 10xAA nimh.
The 2C will hold 3x123 while some people have jammed 4x in them. I found I could not do that reliably. I stepped up to a 3C (which to my sense of aesthetics has better proportions) which will hold 4x easily and 5x if you 1) grind off the anodizing on the inside of the tailcap and 2) install a short spring between the last batt and the inside of the tailcap to make battery negative contact.
You can use 3-D holders. I use 3x3-D in a purple 3D with 9 Powerex 2000mAh nimhs driving wither the 01318 (very bright) or the 01185 (crazy bright). Based on the capacity of my batts, I would expect maybe 35-40 minutes of good light with the 01318 and 20 minutes with the 3.15A 01185. I have a Carley aluminum reflector and UCL and I don't worry about meltage...well, maybe the lamp pedestal now.
As for procuring the bulbs and potting, I conducted 2 group buys for almost $700 worth of stuff in the previous months. While the WA bulbs are relatively cheap (about $2.20 per) and potting by Carley is fairly cheap ($1.73 per), WA has a $100 min and Carley has a $50 min. Still, if you can get enough interested people together, the prospect of getting some honest to goodness 500 lumen bulbs for under $4 is very attractive. You'd be surprised at how few people it takes to quickly get over the mins.
If it sounds like I've spent alot of time thinking about this stuff, it's because I have /ubbthreads/images/graemlins/grin.gif. Guys like Lemlux, Illuminated and Soloco have been most generous with sharing their experience and it's been very helpful.
Wilkey
"Hot Wire Guy"