808 XL or Mega batteries run 380 mAh, I typically saw about a 50% longer useful time between charges compared to a standard KR808D-1 battery. Try vapor4life for those, or possibly litecigusa (I've seen a thread recently where at least some people had overall lifespan problems with recent litecigusa batteries, early failures, though I don't know if that was just a spotty problem, one bad box of them).
A Riva 901, possibly with a 901batt-808carto adapter, is another possibility. The basic kits are pretty cheap at libertyflights. The downside is I'm not sure what the Riva 901 voltage characteristic looks like -- an 808 is a 3.7 - 3.8V device, and at least older Riva 510s were 3.2 - 3.4V, so an 808 carto would run cool (less power); I've heard current Rivas, at least the 510, start at 3.8V or so, but don't know how fast they drop.
Otherwise, just go to a Riva 510 kit, with some boge 2 ohm LR cartos, and/or a 510atty-808carto adapter.
For the adapters, goodprophets tends to have them, as does litecigusa, if libertyflights is out of stock.
Thanks Adrena!
