Well, I got my Protank 4 in the mail from my son in Japan this morning and have had some time vaping on it.
I am a mouth to lung "tootle puffer' using a restricted airflow, and I normally use a Kayfun Lite-Plus V2 with a 1.3 ohm single Kanthal coil and about 12 watts of power.
As far as the Protank 4's RBA section ... For a 'tootle puffer' like myself, I found it to be totally worthless. I admit that I did not try the supplied dual Clapton coils that came with this clearomizer, but I did make a set of dual coils using Kanthal 27 gauge wire. I made 6 wraps around a 2.8mm rod for each coil. The total resistance came out to 0.50 ohms.
Since I 'tootle puff', I made the airflow restrictive and also used a drip tip from one of my Kayfuns on this Protank 4 (did not like the supplied Protank 4 drip tip). Started at 30 watts of power, the vape was very
harsh ... Turned the power down to 25 watts but still harsh ... Turned it down to 18 watts and the flavor was very nice, but not enough vapor production (in fact, very slow to heat the coils and not enough vapor at all ... very little).
So, I installed the supplied 1.5 ohm 'mouth to lung' coil head .... This worked much better with a restrictive airflow and 13 watts of power (still like the vape on the Kayfun Lite-Plus better).
Did not try the 0.5 ohm ceramic coil.
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Here are three other things about this clearomizer I did not like ...
1. When using the RBA deck, the allen head screws that hold the coil wires into the coil posts cannot be tightened up too tight because they will push through the wire ... What Kanger should have done is not make the threaded holes in the coil posts go all the way though the post. That way, once the screws are tighted down on the coil wire, there would basically be a 'stop' in the coil post, and the screw would not continue to push into the wire until the wire is cut (bad design and it keeps the coil wire from being tightened down very much at all).
2. This may only be a problem when the Protank 4 is used with a eVic-VTC Mini box mod .... Even when the Protank 4 is fully screwed into the 510 connector on the box mod, the Protank 4 wiggles. It wiggles because the threading on the Protank 4 clearomizer is just a little too long allowing a slight space between the box mod and the bottom base of the Protank 4 .... I fixed this be pulling out the Protank 4's 510 connector center pin and then grinding down the theaded area of the atomizers 510 connector slightly, which made it shorter. Then reinstalled the Protank 4's center pin and now the Protank 4 can be screwed all the way down on the box mod with no wiggle at all (no gap).
3. After the Protank 4 sets upright for awhile, I sometimes get a slight amount of gurgling from it ... very annoying.
If this clearomizer don't start playing nice, it may just go in the 'round file'.
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All in all, I
may use my Protank 4 as regular clearomizer using the replaceable coil heads. Fasttech also sells these authentic SSOCC coil heads in the 1.2 ohm variety which I think I will use instead of the 1.5 ohm SSOCC heads
And lastly, I am of the firm belief that the Protank 4 was designed for lung hitters and NOT mouth to lung vapers.
Fasttech link:
$8.52 Authentic KangerTech SUBTANK SSOCC Coil Head (5-Pack) - 1.2ohm at FastTech - Worldwide Free Shipping