Just to add my 2 cents...many years ago I bought an Olight S15(I went through a phase where I bought a number of lights that had the option of spare battery tubes). I had ordered a total of 3 body tubes for the S15 so I could run a single 14500, two alkaline cells or three NIMH cells and still stay in the voltage range. When using two bodies, the light flared and died. I emailed and explained the circumstances. Andrew wrote back explaining a number of customers had accidentally put two 14500's in and fried the led. I explained my rationale for having three tubes, and shared a number of lights that I had with multi body tubes. He was very polite, just asking questions to verify that I had not unintentionally used too much power. I returned the light for a new one as easy as can be. I got the impression he had been burned in a couple of cases, yet he was polite, thorough and gladly handled the warranty. As a result I am still a customer Year's later and highly recommend them.