Report Lorus Sports cal. V071 - battery in Japanese Watches Posted February 22 Well gents my 17byr old Lorus needs a new battery and I have bought one (a renata 399) but local jewellers/watchmakers are all shutdown. Can someone please tell me what to do to remove the old battery from the clamp which is holding it? I have managed to unscrew the back and understand about shorting it with the AC terminal. I have fitted batteries in the past to my mrs' watches but they were fairly simple.