I just got a used ego battery off the classifieds because I needed a backup if I happen to lose or break my twist. The actual brand is unknown but it is an ego style 600mah. The battery doesn't fire and the light doesn't even turn on when there is no carto on it. When there is a carto on it the light blinks and still doesn't fire. When I start to unscrew the carto the light blinks very fast. I have checked for 5 click protection and that is not the problem. I have also tried several different cartos. I have no idea what this could be. Any thoughts?