Don't regret starting with the Kr8 and the 510. Those are two of the best models that look something like an analog cigarette, which I suspect is what you wanted originally.
What you should upgrade to now depends on which of those models you prefer ... and on what you mean by battery "power." The
fat batts (e.g., Riva, eGO, and
many others) have much more mAh (i.e., puffs per battery charge) than either the Kr8 or the basic 510, but they
don't have more voltage. In fact, the ~3.4V fat batts are
less than the 3.7V Kr8
batteries. However, they do enable the use of "LR" (low resistance) atomizers/cartomizers, which
will give you more power (i.e., intensity of the
vape, such as TH and vapor).
If you prefer Kr8 cartomizers, get an
Elegant,
Defender, or perhaps a
PigCig: fat batts designed for use with Kr8 cartomizers (and with 901 atomizers). If you prefer the 510 atomizer, get any of the 510-based fat batts, e.g., eGO, Riva, Inferno, Hello 016, VGO, etc. Links to many of the suppliers of these models are included in my
eGOs and Rivas, Hellos, Oh My! article.
Or you could take a leap of faith and get my favorite fat batt: the
Leo, a penstyle (e.g., 801) type. It is not compatible with anything else, but it vapes great. I described the Leo (and provided links to suppliers) in
this review here on ECF.
As you may know, yet another direction to go (and necessary if, by power, you meant voltage) is into the world of
mods. All kinds of choices there. This
multi-part guide can help you find your way.
