Hardware Review: Kanger Subtank Mini

Specs

Material: 304 Stainless Steel, pyrex glass
Length: ~54mm
Diameter: 22mm
Capacity: 4.5ml
Battery Connection: fixed center pin 510 connection
MSRP:  $49.90
What’s in the box:

Kanger Subtank Mini Package Contents

  • (1) Kangertech Subtank Mini
  • (1) OCC: 0.5 Sub Ohm / Range 15 – 30 W
  • (1) OCC: 1.2 Ohm / Range 12 – 25 W
  • (1) Mini RBA Base (with preinstalled coil)
  • (1) Tool Kit (screwdriver,screws)
  • (1) Spare Glass Tube
  • (1) Organic Cotton Square (made in Japan)
  • (1) Spare RBA coil (Kanthal)
  • (2) Spare O-Ring
  • (1) Drip Tip
  • (1) Gift Box
  • (1) User Manual
  • (1) Genuine Product Verification Card

Pros

  • Organic cotton wick (!).
  • Capable of handling subohm vaping.
  • Widely available coils.
  • Available factory made Ni200 coil heads.
  • No leaking (so far).

Cons

  • Slightly higher cost than other similar tanks.
  • Not backwards compatible with previous Kanger coil heads.
  • Spotty availability of OCC coil heads.
  • Sparse availability of Ni200 coil heads.
  • Visible o-rings.
  • Theoretically possibly to vent a mod by using a Ni200 OCC head on a mech.

Errata

OCC heads

The biggest advance with the Subtank by far is the OCC heads. Coiled with “organic Japanese cotton” these are the heads I’ve wanted in a Kanger tank since the original ProTank was released. I started recoiling the original Protank heads so that I could use cotton wick, so it tickles me pink that Kanger is now mass producing cotton wicking coil heads.

First, these new OCC heads are rebuildable. It’s nothing like rebuilding an older Kanger atomizer, but it is doable. I’ll have a post covering rebuilding an OCC head in the near future. Street price is about $12 for a 5 pack, so they’re slightly more expensive than the older BCC heads, but I think the improved flavor and vapor production is worth it. Still I’d like to see the price come down (ideally to ~$1/ea).

One of the biggest challenges with using cotton for wicking is that cotton burns, and once it burns the wick must be replaced (unless you like vaping disgustingly burnt cotton). Kanger realizes this and has included a printed warning to prime your OCC heads before firing your device as the very first thing you see once you open the package.

Alternatively, you could use a device with temperature control with the Ni200 OCC heads that Kanger has released.

Enter the Ni200 OCC head:

Ni200 OCC heads

Expensive but worth it.

The second I saw these I was sold on the Subtank. The best deal I could find on the Ni200 OCCs is currently $3/ea. That’s not a deal breaker, but I’d like to see these available at about $1-$1.50 each. Speaking of available, you know that Kanger has a winner here because it’s not exactly easy to find these things in stock anywhere. The tank comes with two (of the Kanthal coiled ones), and if you can recoil them that makes it kind of a non issue (I’ve no idea how well they will hold up to recoiling, but from my initial examination it looks like they’re pretty sturdy). Then again, not everyone wants to build coils.

If you don’t have any experience with Ni200 wire there is a bit of potential for major problems here. Kanger offers the standard OCC heads in either 0.5ohm or 1.2ohm varieties at the time of this writing. Ni200 OCC heads on the other hand are 0.15ohm. Potentially someone could put one of the Ni200 heads on a device like a mech and vent a battery. If you have a Subtank, you’ve got to watch out for this. If your device has temp control then it’s kind of a non issue, but if you are running a mech, a mix up has the potential to be disastrous. Always verify that your OCC is the version you think it is.

I have a bad feeling that it is only a matter of time before someone isn’t paying attention and accidentally puts a Ni200 OCC head on a mech with an inadequate battery on it and has a really bad way. I could see this happening if you’ve got multiple devices and aren’t paying attention. Unfortunately there is no good answer for potential user error at this time.

The easy way to avoid this is to put the assembled tank on a resistance checker before firing it. Kanger was thinking about this when they released the redesigned OCC heads. The original OCC heads had a white insulator on the bottom of the unit. The new ones have either a red or blue insulator:

Different OCC heads are different colors

Attention to detail

You can see from the picture above that the OCC head with the blue insulator is a Ni200 coil with the resistance and recommended wattage laser etched on one side of the unit. Kanger has done the same with the red insulator heads (coiled with Kanthal).

I switched to a temp control device last October, and I can’t recommend it enough. The major benefit for me is that I haven’t had a dry hit since. The flip side of that is the added expense of Ni200 OCCs. I’ll pay it or rebuild. I seriously can’t say enough good things about having temp control on your device.

For those of us who don’t mind coil building, the inclusion of the mini RBA base is totally awesome. It’s a small deck, but it’s basically like building on a tiny kayfun, except it’s a bit easier because the RDA screws have little ears to catch the wires under the screws (which you can kind of see in the picture of the Mini RBA base in the Maintenance section below).

Airflow control

There are apparently more than one version of the Subtank Mini airflow control out there, the primary difference being the options for airflow control. The version I have has a slot cut on either side of the airflow control ring with three options for airflow: a ~1mm airhole on either side, a ~2mm hole on either side, and wide open which is a large air slot on either side. In this image you can see slightly different options.

Subtank Mini airflow control options

Subtank Mini airflow control

There was a previous version that had an additional fully closed selection, but I assume that Kanger changed that based on customer feedback. I dunno, Since I just got mine, I would assume that it is the newest version available.

Colors

Kanger is also shipping a white and a black coated version of the Subtank Mini (I’ve no idea what they are coated with), but as far as I know those are only available with the Subox kit at this time.

Colors, take two

In my Cons section I noted visible o-rings. For me that is mostly because Kanger chose red o-rings. I’m not a fan of red, but apparently there was a method to their madness as Kanger has put out the “Colourful Silicon Seal Ring Set”:

Is that purple or pink?

Is that purple or pink?

Purple I think

Purple I think

I’ll admit I ordered one, that bluish set will look good with the blue Shark Skin on my rDNA40. I’d still prefer that they not be visible, but that’s just my personal preference.

One final thing to note that isn’t really a con, it’s just kind of silly. Kanger has decided to use a “wide bore” drip tip on this tank. Like all 510 drip tips, it still necks down where it connects to the top of the tank (and it’s not a dripper, so you’re not really going to be dripping into it), so I’m not sure why they felt the need for this. Because of the proximity of the center air channel to the coil in the Mini RBA base, it is possible that occasionally the drip tip will get… warm. Luckily for us this can be corrected by simply easing up on the subohm vaping or even switching out the drip tip for something non conductive for heat like delrin or pyrex.

I also love that they include a spare glass tank section. Thank you Kanger for paying attention. Accidents happen and nothing sucks worse than breaking your only tank when you are about to head out of the house. It’s nice that they’re giving us a mulligan.

Maintenance

The Subtank Mini is really not very different than any other Kanger tank in it’s design, but it is clear that Kanger has learned some lessons about glass tanks over the last couple of years. The basic assembly is the same as other Kanger glass tanks.

Standards disassembly

Standard disassembly

Things to be aware of:

  • When the base is removed, the glass tank is only held in place by the friction of the silicon seals.
  • Filling is just like the previous Kanger BCC tanks, don’t get the liquid in the center air channel.
  • You must prime the OCC heads with a couple drops of eLiquid before firing them or you risk burning the cotton.

 

The Mini RBA base is a bit small, though compared to rebuilding one of the OCC heads it is positively spacious. You can see in this picture that the RBA base disassembles into three pieces, and is very similar to a kayfun, in fact the easiest way to build with it is to follow the same process: coil, wick, pull the excess cotton up while screwing the chimney on, trim it to the top of the chimney, and then stuff the cotton down into the juice channels.

Mini RBA Base disassembled

Mini RBA Base disassembled

There are two things to be aware of when using the RBA base:

  1. The coil sits relatively close to where the center air channel enters the chimney. I have wrapped a 4mm diameter coil in there, but it was uncomfortably close for my tastes. I would recommend building at 3mm diameter or less.
  2. The bottom “pin” of the RBA base actually holds the insulated post to the deck. You need to make sure this pin is screwed in all the way any time you disassemble the tank. I had mine come loose a couple of times. This results in the insulated post lifting, and tilting your coil. This can lead to inconsistent connections, and potentially to a hard short if the coil were to contact the top of the chimney.

Conclusion

While writing this post I fell in love with Kanger all over again. Their attention to detail continues to show, and improve. The original ProTank was the first tank system that I really liked, and the Subtank Mini is a truly worthy successor. Most of the stuff in my list of cons is really superficial, and probably wouldn’t be considered a con by most.

I would really like to see Kanger bring down the cost of these units, and in the past they have reduced the prices on all of their tanks after release so I expect to see some reduction on these in the not too distant future. I paid $29.99 for mine on sale, so the potential is definitely there. Street price is about $35 from many online vendors, I’d expect to pay MSRP from a B&M. The inclusion of the mini RBA base makes it worth it to me, but maybe eventually we’ll see a lower cost version without it.

This is now my go to recommendation for tanks for new or inexperienced vapers. It’s easy to use, and the included mini RBA base offers an easy path for learning to build for those that are interested.

How To: Fix Kanger EVOD leaking/gurgling issues

UPDATE: This apparently works equally well with the Kanger Protank, and other Kanger BCCs with the silicone caps on the atomizer heads. If you’re having issues with those leaking or gurgling, you may want to give this a shot.

A while back I ordered a couple of Kanger EVODs because I wanted something slim for my on the go kit, and the Protank mini was not yet available (I now have two on their way to me).

I’d heard nothing but good things about them, and figured that since they can use the same heads as the Protank, I’d only have to keep one type of head on hand.

They are a great vape. Until they leak/gurgle.

At first I thought it was because I was vaping in +100F temperatures, but even in my 72F house, once I got below about 1/2 a tank the gurgling would start. Then the leaking starts.

Ok look, a quarter ml of juice sitting on top of my battery. Lovely.

At first I thought the problem was with the head. I swapped out the head with a new one from a different package. No dice, exact same problem.

I looked at the bottom of the unit, and the leak was coming through the bottom of the positive contact pin. That precludes the base to head fit being the issue (since the area where they mate was pretty dry).

I thought, well maybe I just got a defective unit. These things are mass produced in China after all, it happens. I tried the other unopened EVOD. Same result. Grrr.

So I took to the internets.

Didn’t really find anything. I found a couple of people complaining about leaking, and others having no issues at all. I deduce from the number of posts I found where people are warning about gurgling after half empty (and saying that just topping off fixes it), that this is a common problem.

I saw multiple comments saying that the juice level dropping below a certain point breaks the vacuum in the tank and causes the gurgling (I also experienced what I would call flooding). I know a little bit about fluid dynamics, and while it sounds good in theory, I’m not convinced that this is the problem. See the fact that there is a hole running through the bottom of the atomizer head into the unsealed battery connection kind of precludes a true vacuum from being present, it’s more of a surface tension effect at that point (but that’s kind of nitpicking). Still, with the viscosity of the juice, and the wick sitting across the top of the hole, and the size of the hole, it should work.

So I disassembled one.

click to enlarge

click to enlarge

I was sure that either the wick or the press fit between the base and the chimney was the culprit.

When I pulled the chimney off, I thought I had found the culprit. The “flavor wicks” that are set on top of the wick with the coil on it in these things are tiny! It was like two little strands of wick, not even an entire wick.

So I looked in my box of parts, and decided to replace the flavor wicks with a single piece of 2.5mm silica (I wanted to use 2mm, but I didn’t have any).

I trimmed the wick to fit, rinsed the whole thing off, filled the EVOD, and put everything back together.

Holy hell the vapor production improved ten fold! Well ok, that certainly had an effect, but did it fix the leak? It took me a while to get low enough in the tank to find out (if I had some 0mg nicotine juice I could have got there much quicker, but all I have is 24mg and 12mg at the moment). I got a hint of a gurgle, and then a mouth full of juice. Took the head off, and now there is like 3/4 of a ml of juice sitting on top of the battery.

Well it did much improve the juice intake.

So I took it all apart again. This time I paid very close attention to the press fit of the chimney and the base. It was pretty dry. I was thinking about the silicone cap and why it would be there. At first I thought it was there to seal the press fit, but looking at the press fit and how hard it is to pull the chimney off I don’t think that is it’s sole purpose. I think it is to seal the connection between the chimney and the stem inside the EVOD as well.

So I took a pair of tweezers and stuffed the cap on the stem inside the EVOD (it was essentially sitting upside down in relation to how it sits on the stem.

The ‘cup’ portion of the cap had to stretch a little bit to fit over the stem. Hmm. I wonder if the cap is just not thick enough to seal the gap between the bottom of the stem and the top of the atomizer head?

click to enlarge

click to enlarge

So I flipped it over on the head. It looks like this:

click to enlarge

click to enlarge

It doesn’t cover the press fit between the atomizer head and the base like this, but I have a back up plan if this doesn’t work.

I filled the EVOD up and installed the head with the silicone cap upside down, being careful to seat the cap over the stem in the top of the EVOD before screwing it down all the way.

I went through an entire tank, down to where I could taste the wick drying out from lack of juice. No leak. It did gurgle a little bit, but I’m pretty sure that is because I let too much condensation build up inside the tip (I was vaping with my mouth only and just immediately blowing it out as fast as I could because I wanted to get it down to where it should gurgle and flood.

NOTE: I used the head that I had replaced the flavor wick with 2.5mm silica for these tests. That may have an impact on the results. I plan to do this with all my EVOD heads as the increased vapor production is great, but I will test it on the next one without doing so first. If that changes the results, I will note that here.

So why does this work?

My theory is that the silicone cap isn’t there to cover the press fit at all (the press fit is tight enough that it’s not going to leak from there). It is there to seal the gap between the chimney and the stem on the inside of the EVOD.

As I mentioned earlier, these things are mass produced in China, and due to the fairly intricate nature of the design and the small size, it is reasonable to assume that the stem on the inside of the top of the EVOD is machined a bit shorter than it should be to ensure a good fit with a bit of ‘wiggle room’ so to speak) for variance in manufacturing tolerance between it and the heads/bases.

Just flipping the silicone cap worked for one of my EVODs, but did not work for the other (apparently the stem is just a hair too short on that one. Time to try out plan B from my earlier experiment. You are going to need an extra silicone cap for this. I took one from a spare head, but I will start saving the reusable parts from heads in the future:

click to enlarge

click to enlarge

Now take that second cap and put it on the head upside down. It’ll look something like this:

click to enlarge

click to enlarge

Time to fill her up and try it again.

I was able to get the base screwed down almost all the way (don’t force it or you risk breaking the top of the EVOD). Mine had just a hairsbreadth of a gap between the base and the top piece, plenty of room for the silicone o-ring inside the base to seal it up nice and tight.

Worked perfectly. No gurgles, no flooding (this time I wiped down the tip with a napkin when the condensation got built up), no leaking.

This is an easy fix; Kanger needs to make the top of this silicon cap just a hair thicker. Or maybe make the ‘cup’ part double sided. Either should work and is a really cheap solution to this occasional problem.

If I could not have gotten this fixed, I would never buy another EVOD, and this post would have been a review of the EVOD telling people not to waste their money.

As it stands, I’m ok with it. The EVOD works fantastically after this simple modification, and even better with the larger flavor wick.

end