I've had a Smok Stick X8 for about a year now, and today it started giving me grief. It doesn't appear to be charging - charging light would go off after about a minute. Battery is not fully charged as I can heardly get a vape out of it (not atomising). Tried several different cables, same effect. Swapped out the coil, same issue, so not a faulty coil either. If trhe battery is indeed dying or dead, can it be replaced? I know it's not a buildable, but seems a shame to chuck an otherwise perfectly good stick and buy a new one, when a replacement battery would cost about half the price of a new stick?