SONY VTC6 18650 3000MAH 15A BATTERY
What a difference. I've been using some year-old Samsung 18650, 2500MAH batteries and the charge has been (understandably) worsening more and more recently. After reviewing some batteries, a lot of suggestions pointed me to the Sony VTC6 and I can say that I'm very thankful that I went with these. Well built and they hold a very long charge.