My L7 Digital Lumamax had been sitting around for years - the original B90 batteries didn't hold a charge very long even when new. So I asked some very talented friends if we could modify it to accept one or two 18650s. Turned out 2 18650s was a touch too long, but one works great! I love the beam pattern with the perfectly round hot spot in the middle and the wide softer circle around it. It's become one of my favorite lights for around the house.