Dave,
sit down with a little paper and a pencil.
The NCP 630A, low dropout regulator, is a linear regulator, right?
a 14500 Li-ion cell is 900mah @ an average of 3.7 volts, the same as an eGo 900mah cell (3.33 watt hours)
Stacking 900 mah cells to give 7.4 volts gives 900mah @ 7.4 volts (6.66 watt hours).
If you run the mod @ 5 volts, about one third of the power will be lost as component heat.
If you run it lower, say 4.5 volts, about 40 % of the battery energy is lost.
If you run it about the same as a 3.7 volt e-cig with a 1.6 ohm carto, lets say a 3 ohm carto @ 5 volts, 1.66 amps, 8.3 watts,
4 watts will be lost.
Make a list of the possible carto resistances you might like to try. Then figure the range of voltages that would be applicable.
I know people that run VV with 1.6 ohm mega dual coil cartos at about 4.2 to 4.5 volts.
The most efficient voltage with a linear regulator is at the highest output you can run.
If you want to run 14500 cells down to 3.5 volts loaded, stacked 7 volts, with about .5 volts lost in the regulator, 6.5 volts is the practical upper limit. Fully charged, 7.8 volts loaded, 6.5 volts out, down to 7 volts loaded with 6.5 volts out. Figure the losses. The 14500 has about a 2 amp upper limit (some claim to run 2.5 amps). A 4.5 ohm high voltage atty would give you about 9.4 watts at 6.5 volts. Electrical losses would only be about 12%. That's pretty good. Run time with a pair of quality 14500 cells would be better than a 900mah eGo.
VV mods with a pair of smaller cells, like maybe 16340, 600mah cells, and a 90% efficiency switching regulator would also have a better run time than an eGo. A little better
The sealed or unsealed 510 connector will be sealed when the positive lead wire is soldered to the center pin.
The auto battery 510 had the hole left open to allow air to operate the switch. Most mods end up with the connector sealed by default.
