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Risks In More Wattage

The race for more wattage rages on. At the writing of this article, there are a number of mods released that go well past the 30 watt mark. Until they started using multiple batteries, I was not concerned. With multiple batteries, there are risks for the safety of vapers – especially with dual, triple, and even quad battery mods being released to achieve high wattage.

Do we need higher wattage?

That's actually a good question. When we started vaping using an eGo battery and basic clearomizer, we were vaping at 6.52 watts. As we progressed to variable voltage, most of us settled on about 4.2 volts (roughly 8.4 watts). Knowingly or not, most of us found that 8.5 watts was the "ideal" wattage for our daily vape.

Many of us found that some eLiquids needed an extra kick to get better flavor or more throat hit and experimenting with different voltage and wattage levels started. For a long time, my favorite mod was the Cool Fire 1 delivering a constant 8.5 watts. Then I tried variable wattage devices and haven't looked back. I still vape at 8.5 watts most of the time, but I have kicked it up to 12 - 13 watts with some regularity. I have tried higher – all the way to 100 watts on a recently released Sigelei 100 W.

Still, I keep going back to 8.5 watts with most juices.

I review quite a few products and lately I have refused to review anything with more than a single battery, unless the batteries are connected in parallel. I will not use any device with more than one battery connected in series – not again.

I am going to first discuss batteries connected in parallel. The graphic at the right shows what a "parallel" battery connection is. In the illustration I am showing two Samsung INR 18650 2500 mAh batteries. These are rated at 3.6 volts with a maximum constant discharge rate of 20 amps. For a parallel connection, you are connecting all the negatives together, and all the positives together. Then one positive lead to your positive post of your device, and the negative lead to the negative post of your device.

When you connect batteries in parallel, you are doubling the amps and the voltage stays the same. So, you still get 3.6 volts (nominally), but the maximum continuous discharge rate jumps to 40 amps. You also double the capacity, 2500 mAh becomes 5000 mAh. In effect, you are getting double the time between recharging the batteries and have a much safer experience if you decide to use low resistance coils.

When you "stack" batteries, you are connecting them in series. This doubles the voltage, so in our example we will end up with 7.2 volts nominally (8.4 volts with a fresh charge). To connect in series, the positive of one battery goes to the negative of the next, and so on.

We already know that advanced personal vaporizers have the ability to adjusting either voltage of wattage. Increasing either will generate more vapor, provide better flavor, and increase throat hit.

With a one battery system, the regulated mod will adjust the wattage and amperage to achieve the higher voltage dialed in.

The issue with doubling the voltage is that we are not doubling the amperage. Connecting in series means that the amperage remains the same – in our example, what we end up with is 7.2 volts and only 20 amps for maximum continuous discharge power.

Regardless of how you connect your batteries, if you increase the voltage or wattage going to your atomizer, it's the amps draw that causes the internal resistance inside the battery – and that creates heat.

Each battery you buy has a maximum continuous discharge rate. That should be your guide for your every day vape. Those batteries also have a rate for maximum pulse discharge rate ... that means that it can exceed the maximum continuous discharge rate for a "pulse" (usually 1 second or less). With the Samsung 25R used in the example above, the maximum pulse discharge rate is 100 amps for 1 second or less. In the parallel example, that doubles to 200 amps for 1 second or less (that is in addition to doubling the amp rating to 40 amps).

Do what ever you want, you just can't get away from the law of physics. Ohm's Law, the relationship between volts (voltage), current (amps), resistance (ohms), and power (wattage) will remain the same whether you connect in parallel or in series.

Connecting batteries in series is a disaster waiting to happen. You are doubling voltage, but let me word it in a different way: at the same voltage, you are cutting the amps in half and increasing the possibility of blowing up your batteries. It's a cheap way for China manufacturers to get bigger clouds, but it's at an increased risk for you.

As of October 1, we have refused to accept any devices for testing and review that have more than one battery and are connected in series.

Here's the list of multiple battery devices:

ModConfigurationWattage rangeConnection typeChipset
Sigelei 100W dual 18650 batteries 10 - 100 watts  connected in series proprietary
Heatvape Invader / Dovpo E Mech dual 18650 batteries 7 - 30 watts  connected in series unknown
GI2 Box mod (clone) dual 18650 batteries 1 - 100 watts connected in series proprietary
IPV 3 dual 18650 batteries 7 - 150 watts connected in series SX 330 v3S

I will test and review the IPV 3 when it is launched, it is the only one claimed to be connected in parallel. Of the other devices announced so far, I have tested the Heatvape Invader – it was the one device that initiated the concern and research into risks of vaping with batteries connected in series.

The claim that the Pioneer4You IPV 3 is connected in parallel is false. The Pioneer4You IPV 3 is connected in series. The chipset (YiHi SX 330 V3S) offer no protection and no step down capabilities. 

At this point, the only multiple battery advanced personal vaporizer worth considering (safely) is the Cloupor T8. Cloupor is making the claim that their chipset has built in step down and limits output voltage to 7.5 volts. The only YiHi chipset that has step down functionality is the SX 350, but there are no commercial devices released with this chipset yet.


  • Posted by Joe Hamel on March 4, 2016, 9:44 pm

    You do make some valid points here but one critical aspect you've neglected to discuss is the correlation between a set of series connected batteries per the required amp draw to fire at X.XX resistance vs a set of parallel connected batteries amp draw to fire the same resistance.

    10 amps @ 3.7v is alot different than 10 amps @ 7.4v

    To get to a defined power level, say 100 watts you could use parallel so 3.7v with a resistance of 0.14ohm will give you 100 watts @ 27.03 amps

    In series 7.4v with a resistance of 0.55ohm you'll get 100watts @ 13.51amps

    Its all relative to the resistance you're using and the power level you're trying to achieve so it's kind of presumptuous to take an opinion that series connected batteries in general are bad, really it's all about the the quality of the products being used and if the user has the required knowledge to not put themselves in a dangerous situation.

  • Posted by Joe Hamel on March 4, 2016, 9:32 pm

    You do make some valid points here but one critical aspect you've neglected to discuss is the correlation between series connected batteries per the required amp draw to fire at X.XX resistance vs a set of parallel connected batteries amp draw to fire the same resistance.

  • Posted by kurt shamie on April 27, 2015, 6:44 pm

    I just bought a Ecigator Gox50 Gator box it takes 2 18650 in parallel would you say this is safer with a .2 coil in a Arctic sob tank at 40-50 watts than it would be in my Sigelei 100w with the same sub tank at .2 when the Sigelei is in series? I want to vape safe so in your opinion if I am using dual batteries I should only use them parallel? I only use sub ohm tanks like arctic,Heraklus, Atlantis etc... .2ohm up to a .6 ohm and never over 70 watts so you recommend if using dual battery box mods to stick with only parallel ? Also am I safe with an ipv mini 2, 70 watt that takes only 1 battery with the same sub ohm tanks and coils that I spoke about above?

    Reply> We cannot give you an answer to the question you asked about parallel vs in series connected batteries. We have documented the issues with both types of dual battery connections. We have not tested or reviewed the device you are asking about and cannot comment to that. And, yes, you are safer using a single battery.

  • Posted by Gabriel Selmi on November 28, 2014, 12:27 am

    Thank you for this very important and interesting informational article. I have an E-Mech as listed in your table and have some concerns on battery safety. if I run atomizers with resistances that are well within the range of one single battery am I still at risk with the batteries in series. For example, running a 0.5 ohm atomizers with 20 amp batteries?

    Thank You

    Andy>> Dovpo have their specifications for the E Mech posted and claim the batteries are connected in parallel. The Heatvape Invader specifications claim the batteries are connected in series. Regardless of which, I would run a coil resistance that is nowhere near the extremes of the range (0.35 to 5.0 ohms). I personally would not go sub-ohm and would not exceed 2.4 ohms. And, to be safe, use the best quality batteries you can find.