Surefire E2E.........

I have had this light for around 7 years. It has mostly sat in the bed stand drawer for 5 of those years. I decided to get a TNVC E2 head to make it a LED light. My question is what rechargeable batteries can I use in it? 18650, 17670, or RCR123A? I guess I am mostly wondering about which ones will fit and which set up would be best?

18650 will not fit.

17670 might fit; general consensus is that the older E2Es fit them while the new ones have a slightly smaller bore and do not.

two RCR123s will fit, but two of these have less Watt Hours than a single 17670.

My suggestion is to buy a 17670. If it fits, great. If not, you can either bore out the body using sandpaper and a dowel, or you can sell the 17670 in the marketplace and go with RCR123s. Keep in mind that if the LED dropin calls for 6v or more, then you have to buy the RCRs (the 17670 is only 4.2v fully charged).

Thanks for the information. I will probably be going with the RCR123's if the 18650 wont fit. Should work fine. The voltage for the TNVC head is 4.5v-10v.