I do have an efest luc 2 way charger, stops charging when charged and has a volt meter. I don't have a screen on my mod but now that you mention it I do feel a change in power when the battery meter gets near halfway. I am somewhat new to the vape game. I've been around them, talked about them, always asking people for them, plus some of my friends give me some good knowledge. I finally got around to buying a kanger tech sub tank plus and a Kbox cause I felt annoying always asking for some ones. I have an indulgence mutation v4 rda with matching mod stick coming in the mail (that's what the tiger coils were initially for) but I didn't realize a single 28g coil can reach pretty high ohms, I was looking to build a dual coil running around .4 .5 ohms.