I machined up these adapters to allow me to use my old Vista Light housings that take MR11 halogen globes with the new P60 LED drop in modules. The P60 drop in modules are available in a great range of LED options including R2's, P7's, XPE's, XPG's and even SST-50's.
I made two adapters to test, a larger one for more heat dissipation and a smaller one which doesn't really extend much beyond the vista light housing.
Both work well, although the smaller one does get warm to touch after about 5 minutes when using a P7 module. For night riding when the light is moving I have never experienced any heat related issues with either adapter size.
A picture tells a thousand words:
Short adapter
Grub screw holds P60 module in place (on the longer adapter I used an internal o-ring in a machined groove to hold the P60 module in - both approaches work equally well):
For the 'short' adapter I also machined down the reflector on the P60 module. This resulted in a slightly broader beam/better spill on the R2 module I used initially.
Large adapter
This version was made longer to dissipate more heat. Here it is assembled in the Vista housing:
Wires are soldered to the contacts on the back of the P60 module and then pushed into the halogen contacts. Be careful to get your polarity right! This image also shows how the rear of the adapter is beveled to interface properly with the bevel inside the vista light housing. Getting a good fit here is essential for heat transfer from the module adapter to the vista light housing.
Weather proofing
The adapters provide no weather proofing for the modules. In a normal flash light there would be some glass in front of the module. The lack of weather proofing is not ideal but providing a cover would have complicated the build considerably.
The first adapter I made was really just by way of a proof-of-concept. However, after over 2 years of extensive use I am yet to have a weather related failure of a module, but I haven't done a night ride in all that time in a torrential downpour or through lots of mud. Ordinary rain under a forest canopy cover doesn't seem to be a problem. The coating on the reflectors does not tarnish either and the dirt wipes off easily with a soft wet cloth.