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Inexpensive Variable Voltage eCig Review – Vari Stack from iVape

The Vari Stack variable voltage electronic cigarette is one of the least expensive variable voltage devices on the market. Ever since the arrival on the e-cigarette scene of the LavaTube, variable voltage has caught on in a big way.  Once predominately the domain of American-made devices like the Darwin and ProVari, Chinese factories have started to really pump out the variable voltage devices.  We’ll take a look at how the budget oriented Vari Stack, well, stacks up in this inexpensive variable voltage ecig review.

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Who’s the Vari Stack for?

With its low price tag, it’s fairly obvious the Vari Stack is geared towards price sensitive vapers.  This advanced personal vaporizer (APV) may also be popular with folks who like a little color choice other than black or silver in this device. However, this device uses two batteries so it is definitely not for those uncomfortable with stacked batteries or unfamiliar with battery safety. The amperage limits will also keep fans of dual coil and low resistance gear on the sidelines.

If this sounds like you, you’ll find the Vari Stack at iVape

The Vari Stack’s Design

Have I mentioned this is a budget-friendly device? This becomes painfully obvious in the fact the device is constructed of plastic.  The good news is that plastic is much easier to color, and as a result the Vari Stack is available in a range of colors. The plastic has a good feel to it and naturally, makes the Vari Stack feather-light.

Vari Stack Held (I need to start getting manicures if I'm going to keep doing this)I have to admit, the Stack actually looks better than it did in the pictures I saw before ordering.  It is cylindrical at the base which then tapers up to a sort of squarish design which houses the LED display, fire button and voltage adjustment buttons.

The device has a very good feel to it when being held.  The flat part seems to be exactly in the right spot.  Button placement is equally well thought out.  The button itself is fairly small, but has good feedback with a responsive click.

The adjustment buttons run the e-cigarette through its range from 3.0 to 6.0 volts.  The display is also capable of displaying the device’s sole error message, “Lo” which seems to indicate everything from over voltage to low battery and every thing else in between.

Unfortunately that Lo display will pop up a bit if you are a low-resistance fan, thanks to the underwhelming 2 amp current limit of the circuitry.

Moving up to the top of the device, you’ll find a basic 510 connection, with no drip well.  I found that many of my cartomizers had trouble making a solid connection to the battery post.  This seems to be a result of the 510 connector’s top being fairly high.  I tossed a shorty 510-510 adapter in-line and everything was great after that.

Vari Stack with adapter

On the other end of the device, the end cap has two vent holes, and unlike most tube style devices, the end cap doesn’t screw on.  Rather it has a keyed sort of setup.  To attach the end cap, line up the slots and push it into place, then give it about a 1/4 turn to seat it into place.

It’s important to twist the cap on fully as it uses small metal contacts in the side of the cap to complete the electric circuit and deliver power from the batteries to the device’s controller.

Battery Safety

That power is supplied by two IMR 18350 batteries.  This of course means that extra care regarding battery safety needs to be applied when using this device.

For starters, using the right type of batteries is paramount.  Always use the proper batteries. Here’s the battery recommendations from the vendor’s site:

Please do not use unprotected batteries or batteries with a C rating lower than 4.  Do not tamper with batteries, IMR Lithium batteries can be very volitile.  This mod uses batteries in series, something that iVape never recommends.  IF you choose to use this mod you must understand proper controls of lithium batteries and are accepting all liability from any misfortune caused by use of this device, or a battery failure when using it. Please be sure to look at proper instructions and handling for Li-ion batteries before handling.  You can not use 18350 with pcb, or dual coil applications with this mod.  This item is picky about batteries it takes, and may not function correctly with all brands.

vari stack with 2 batteriesI’ll also add, that you should always charge the pair of batteries together and remove them from the charger as soon as they are charged.  You should also use a multi-meter and test the batteries frequently after they come off the charger to make sure they are not charged beyond the limits set by the manufacturer.  In general, you should know what you are doing if you use a “stacked” device.  This review can’t cover everything, so I suggest finding an appropriate guide online.

All that being said, there are some things in place on the device that should help with safety.  The first being this is an electronic device that has protection circuitry designed to kill the power if there is too much current draw or voltage going on.

The Vari Stack’s construction also seems like it would be a minimal risk of actually exploding due to the batteries venting gas.  The fact it is plastic and has a seam running through it means that gas would likely either break through those seams or through the end cap’s vent holes (or just blow the cap off since it’s also plastic and not screwed on.) The device’s very low 2A limit will also minimize the chances for a battery to run away.

In general, have a healthy respect for the power of lithium batteries in any device, but especially in devices that use multiple batteries.


Ok, now that we have the scary stuff out of the way, let’s talk about using this thing.

Vari Stack Display Closeup

I’ve mentioned it several times, the device has a very low limit of 2 amps.  This is going to limit performance to some degree.  First of all, if you are a dual coil cartomizer fan, this device isn’t going to be for you.

I also struggled with 2 ohm cartomizers as well.  They would fire up, but would frequently give me the Lo error message and briefly interrupt power to let me know it was displeased with me.

That does, however, point out an interesting feature on the Vari Stack.  Unlike the ProVari which shuts you down if you exceed amperage, or the Lavatube which dumbs things down, but doesn’t tell you, the Vari Stack has a different approach.

If you exceed the amperage, the device will shut off and display the message.  However, if the load falls back into normal specs, everything will kick back on.  If you’re close to the limit, you may notice just a brief skip while you’re vaping as the circuit kicks in and then resumes.

I prefer this approach as it’s not as disruptive while still telling you that you’ve taken things too far.  However, this happened a lot running a 2 ohm cartomizer anywhere from 4v-3.7v.

CE3 on Vari StackOnce I switched things up to my Vapor Alley CE3s which ring in at 3 ohm, things got much better.  I ran that carto between 4.5 and 5 ohm with only the occasional Lo warning (possibly due to heat, not amperage). I stuck to under 5 because that’s more a limitation of that cartomizer’s ability to wick. A 3 ohm cartomizer should top out right at 2 amps when used at 6 volt.

When putting the Vari Stack on a multimeter, I noticed voltage was a bit less than the setting on the device.  This seemed to be worse at lower voltages with 3.7v metering out at 3.4v. Beyond 5v things seemed to line up.

This could be the device compensating for the loaded voltage.  However, I was unable to get on-load readings because the Vari Stack uses a pulsing voltage regulator which my volt meter is unable to read.

A pulsing voltage regulator also means that less heat is released through the circuitry, which is a good thing.  I never noticed my device getting overly warm while vaping.  This also lends itself to better battery life.

Even with small 18350 batteries, I was able to get several solid hours of use before the batteries ran down.  At least I assumed they ran down since it would simply start displaying the Lo message and cutting off and then resuming repeatedly.

Too Long; Didn’t Read

Vari Sack review TL;DR

The Vari Stack is a very pocketbook friendly variable voltage device constructed almost entirely of plastic.  Plastic construction means more color choices and a light weight. Unfortunately, the requirement for two batteries and a low amperage limit reduces the potential appeal the Vari Stack could have.  Then again, if you are looking for an inexpensive variable voltage solution that is a little different (and are up to speed on batteries and use 3 ohm gear), the Vari Stack is not a bad choice.

You can pick one up at iVape.


  • Very affordable
  • Light weight
  • Good ergonomics
  • Looks better in person
  • Available in a rainbow of colors


  • Uses stacked batteries
  • 2 amp circuit
  • End cap can be tricky and feels cheap


Product: Vari Stack Mod
Available From: iVape
Price at time of writing: $39.95
Threading: 510
Batteries: 2x IMR 18350