An automatic 510.
I'm not being flip. There are such things. Most suppliers sell only the manual batteries, but a few also offer the automatic. I don't personally recommend it: it can be triggered by sound and movement, not only by sucking. But it does work and, since the atomizer is the same, the vapor production is outstanding. [
I don't get throat hit from the 510, but most people do.]
The two suppliers
I know of (there probably are others) are
Cignot in the U.S. and
Heaven Gifts in China. Both sell the
Joye 510 model, not a knock off. Cignot's starter kit has the option of one automatic battery and one manual battery (or just two of the same type). I urge you to consider this option; the manual is the superior battery (on the 510, not necessarily on other models). And, yes, there is a USB passthrough for the 510. Since most (not all) 510 passthroughs have an inline battery, it is not as powerful as many other passthroughs, but it does deliver constant power to the atomizer at the same level as the 510's battery.
There is
another direction you can go: Use Kr8 automatic batteries (and an adapter) with 510 atomizers. In my experience, the Kr8 auto batts are among the most effective ... and, at 280 mAh, they deliver more puffs per charge than the 510's 150 mAh battery. I know of two one-stop-shops for this (i.e., purchase Kr8 starter kit, adapters, and 510 attys):
AltSmoke and
NHaler.
Heaven Gifts has all the parts (including adapters), but not an auto Kr8 starter kit. [
GoodProphets is another source for adapters.] Of these, only
NHaler sells a Kr8 automatic passthrough (which delivers more voltage to the atomizer than the typical 510 passthrough).
I've continued to tie recommendations into the 510 atomizer because of your criteria of "Lots of vapor" and "Easy to refill liquid manually."
However, I have had to
ignore your "Heavy voltage" criterion. Other than some passthroughs (virtually all manual), any e-cig with voltage higher than 3.7V is a mod; and all mods are manual.
I've already provided one source for an automatic direct* Kr8 passthrough. Two others are
Vapor4Life and
VaporKings.
* direct: no inline battery; provides 4.2V to 5V to atomizer.