Hi, I'm on to my second ecig purchase( have spent around £100 so far on starting although I believe that there is always going to be an initial outlay through experimentation) bought the riva 510 which is an improvement on my prev one. Also got some dual coil carts which are very good. However someone has advised against using them with riva as battery not suitable and thus can damage it. My previous purchase batt only lasted 4 weeks (40quid - no good) so I don't want to mess the Rivas up or chance it. What are your recommendations for s suitable battery for the dual coils?