Ok, now I've heard the 510 batteries can be crappy, but I guess I assumed they meant as far as battery life.. I had gotten an adapter and 808 cartos to try on my 510 and I noticed the vapor is really light- not as dense and sorta "creamy" I guess I could describe it..? Also the flavor isn't really very good for this juice. I'm trying to figure out if it's the blank cartomizer I ordered or is the 510 battery not quite strong enough for the cartomizer. However, we also do have an e9 kit. I noticed the blank 808 cartomizers I bought has a different sort of batting than the e9 cartos my husband has- his looks more like a smoother batting, while my 808 carto filling looks to be more of a "looser" fiber poly batting- I'm able to compare and say that the 510 with the 808 carter is really bad compared to our e9 is why I'm wondering if it's the particular carto I ordered, or is that just the way the kr808 is? I also tried my 808 carto on my husband's e9 battery- it doesn't exactly fit perfectly, but the threads do line up and it kinda works- but the same not so good output as on my 510 battery. (but is that because it doesn't line up perfectly and battery not connecting all the way or something?) I was hoping someone more experienced might be able to help me shine a light on this before or instead of buying an entire kr808 starter kit to figure this out! 