One of the few automatic large battery PVs is the 1300 mAh Kr8-compatible
Echo (which I
reviewed in June), e.g., $40 for a complete two-battery kit from
SmokTek. Although it is fully compatible with standard Kr8 cartomizers, it is especially effective with its own 3ml-capacity cartos. I recommend the
dual coil ones. It is a very good model and the auto batteries work like a charm, but I've found that I prefer manual batts and don't use mine that often.
However, rather than getting another fat batt, it sounds like you are ready for a
mod. There are so many really good ones to chose from. My
Wonderful World of Mods outlines the parameters to consider. That guide was written over a year ago and many more models have come out since then, so also peruse ViZi's outstanding
e-Cig Mods Database and read/view reviews here on ECF.
I recommend either an 18650-based 3.7V mod (for use with LR cartomizers) or a variable voltage mod (for use with an atomizer or cartomizer of
any resistance). There are far too many good 3.7V mods (in various price ranges) to list here. [From my small collection, I am loving my $130
Empire Mod, which I won in a contest. And I've even gotten used to the .... switch...
...but my $35
NoEgo gets the job done quite well. As with most mods, batteries and charger are sold separately.]
[18650 NoEgo on left next to 14650 version and eGo]
Assuming for the moment that you would prefer tube over box shaped, one of the most intriguing and least expensive VV mods is the LavaTube, soon to be sold by Volcanoecigs for under $100. It has been reviewed by
CyberWolf,
Steve K, and
HawtAngel.
Whatever mod you get, I urge you to give strong consideration to one of the cartomizer-surrounding tanks to put on it. They have become immensely popular and are offered by many suppliers. Not only do these eliminate the need for frequent carto filling or top-off, but they continuously keep the the atty portion of the carto very moist, constantly providing an optimum vape. I am thoroughly enjoying my 3ml-capacity $55
VPX Cartomator Stainless Steel Tank, which I received as a gift.
But there are less expensive delrin (and/or higher-capacity) tanks available, e.g., the 6ml $13
SmokTank XL.
Many others are described in
this Guide to Vaping article.