okay..here is what I have learned with 808 d batteries. Sometimes the connector is pushed down too far. I use a bent paperclip to take the rubber caps off my cartomizers when I refill them. I assume you have something of that sort as well. What you do, is take your bent paperclip on one hand..take your battery in the other hand, and insert the end of the paperclip into the hole in the tip of the battery. just put it in a few centimerters..then kind lift up the paperclip on the edge of the batter, so it slightly moves up the battery connector. I do it once on one side, then on the other to even it up. Bingo..your battery should work fine. I was ready to throw away 2 batteries till I discovered this.