It's worth pointing out that the word "eGo battery" covers a variety of products - many not "eGos"! Some eGo style batteries will not cope with LR atties and the mosfets in the battery will be damaged, I have also come across others (eg vGo batteries) which will detect an LR atty and refuse to work with it. Even with real Janty/Joye eGo batteries I would advise using batteries bigger than 650mah to give the battery a bit of "room to cope". I've used very low resistance atties with big Janty eGo batteries (eg a Cisco 1.5ohm 306) and had no problems, but you are to an extent "pushing your luck"