This probably isn't an issue but I'll post anyway. I've got three AW IC Protected 3100mAh 18650 batteries (Black battery, Silver label with a vertical red stripe on the labels negative side. They are expensive and I get them from AltSmoke.) and a TrustFire TR-001 charger. I've been vaping for almost nine months now with the same batteries. Each being charged once a week. A few weeks ago, after they would fully charge and the chargers green light would come on, my multimeter is reading 4.0-4.1. They used to always read 4.2. Could the charger be getting old? Certainly the batteries aren't that old. Each battery lasts me about two and a half days. What do you guys think?