This modification is mentioned in a thread from years back, but messages are a bit mixed, and photo links are broken. I took a gamble, and was able to make it work.
Obviously, the Eiger heads on Sapphire body are trading run time for output. I custom ordered single mode Eiger w/ 4000k Nichia 219b and added an extra Ultra head with same LED.
I am currently using a flat top Efest 10440 with a tiny blob of solder on bottom of battery (wouldn't make contact to bottom of Sapphire without that blob - YMMV). I have flat top NiMH AAA in the mail. The first batteries I used were button top. They worked fine, but left a bit of O ring exposed.
Pics:
Obviously, the Eiger heads on Sapphire body are trading run time for output. I custom ordered single mode Eiger w/ 4000k Nichia 219b and added an extra Ultra head with same LED.
I am currently using a flat top Efest 10440 with a tiny blob of solder on bottom of battery (wouldn't make contact to bottom of Sapphire without that blob - YMMV). I have flat top NiMH AAA in the mail. The first batteries I used were button top. They worked fine, but left a bit of O ring exposed.
Pics: