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How to Build Unregulated Dual 18650 Box Mod with MOSFET


In this article, I am going to show you how to build unregulated box mods.

So you love your mechanical tube mods, who doesn’t? You also love that unregulated power straight from a freshly charge battery. But you are looking for a little bit more vape time.

If this sounds like you. Than building an unregulated dual 18650 box mod might be the perfect choice. This box mod holds two 18650 batteries which will give you much longer vape time when compared to a single 18650 tube mod. Wiring this box mod in parallel will also increase amp limits for safer sub ohm builds.

This unregulated box mod is one of the easiest mods to build. Definitely suited for both advance and newbie builders. Just because this mod is easy to build doesn’t mean we can’t add in some cool features.

The first thing that we will utilize is a MOSFET. By using a MOSFET, we will be able to use any fire switch that we want without worrying about amp limits. We are also going to wiring in optional 15 amp fuses.

Wiring these fuses in parallel will give you a holding limit of 30 amps and a trip limit of 60 amps. This is purely a safety feature and can be omitted if you practice safe battery usage and understand ohms law.

Another optional safety feature is to include a master on/off switch. This switch will allow you to cut off all power to your atomizer. So you can now carry this mod in your pocket or bag without the fear of it firing.

So if you are interested in building this exact unregulated box mod that I show you in this video, I do have complete DIY Box Mod Kits available to you. You can find these kits at www.Shop.FindMyVapes.com

IMPORTANT: I do regularly stock these kits but they do sellout fast. Please be patient if they are out of stock, more kits will be stocked soon.

I will go over every item needed to build this unregulated box mod. I will also include links to each individual part in case you would like to piece together this box mod yourself.

What You Need:

Tools You Might Need:

Alright that’s everything.

Let’s Start Building!

The first thing I like to do with every box mod is to sand and even out the enclosure. Many of these project boxes come with slightly slanted sides. This will cause your atomizer to sit at a slant. If this doesn’t bother you, then you can skip the sanding step.

To sand the enclosure, I simply use some regular sandpaper and a flat surface. I then slowly sand each edge of the enclosure until I am satisfied with the even angles. Again, this is optional and can be skipped.

Laying It All Out

Box Mod LayoutAfter I get my enclosure exactly the way I want. I will now plan out the placement of each individual part. I usually start with the battery sled and modify it if necessary. Typically this involves sanding and rounding out the bottom right corner of the sled.

Next you need to decide where you would like to place your 510 connector. I usually like it in the center of my box mods but you can move it to the right or left depending on your own preferences.

Now comes the fire switch, like many box mods, I place my switch on the top left of the enclosures. Again this is personal preference and you can place it on any side.

If you decide to follow the same layout of my box mod that I show in the above video, then you will be left with a perfect spot for your MOSFET and on/off switch.

Drilling Out The Holes

You can now move onto drilling out all the necessary holes for your unregulated box mod. For this project, all we need to drill is the hole for the 510 connector and the fire switch.

Many of you have asked how I drill out my holes for box mods. I have dedicated a whole video on this topic. The title of that video is “MOD TIPS #02 – How to Drill Holes for Box Mods” which I definitely encourage you to watch.

Wiring Everything Up!

Here is the simply wiring diagram that I have created just for you. This is the diagram that we will follow to complete our unregulated box mod.

Dual 18650 Wiring Diagram

Please watch above video for more detailed wiring instructions. It is not possible for me to put all the steps in writing.


Mosfet WiringWe want to first take a look at the MOSFET. You will notice that there are 3 legs on the chip. The first leg is known as the “gate”, this will connect to the master on/off switch which is also connected to the fire switch.

The second (middle) leg of the MOSFET is called “Drain” and will connect to the outer housing of your 510 connector. If you are using a Fat Daddy or Varitube spring loaded 510, you will want to connect this leg to the negative connector on the 510.

The last leg of the MOSFET is the “source” and will connect directly to the negative contacts of your battery sled.

Before wiring any of these legs, we need to first solder the 15k ohm resistor to the MOSFET. This 15k ohm resistor will connect to the outside legs of the MOSFET which is the gate and source.

I personally prefer to solder the 15k ohm resister to the backside of the MOSFET. This is just my personal preference but if you look at the MOSFET, you will see that there is a perfect empty spot for this resistor.

After soldering all your connections to the MOSFET, go ahead and use some heat shrink tubing on all connections. This will prevent the legs of the MOSFET shorting out on each other.

Now that the MOSFET is done, let’s move onto the battery sled.

Battery Sled Wiring

Since we are wiring this unregulated box mod in parallel, we will need to wire the battery sled so that the negatives are connected together and the positives are connected together. This will produce the 4.2v battery output and also double the mAH of your mod.

The negative contacts will be connected together with a short piece of 16g wire. Go ahead and solder the contacts.

The positive contacts will also be connected together but it will first go through two 15 amp fuses. This will give you the 30 amp hold and 60 amp trip as mentioned earlier.

Once you have prepared your battery sled, start protecting each connection with heat shrink.

Master On/Off Switch Wiring

Looking at the on/off switch you will see that it has 3 separate legs. This is pretty simple to wire because we are only going to use the middle leg and one of the outside legs. You can use either outer leg that you want.

Whichever outer leg you choose will become the “on” position. The legs on this on/off switch is longer than we need so I always like to trim them down before making my connections.

The middle leg of the on/off switch will later be connected to the MOSFET and the outside leg will end up connecting to the fire switch.

510 Connector Wiring

A standard 510 connector wiring is pretty straight forward. The middle pin is the positive connection and the outer housing is the negative connection. Simply solder your 16g wires to the corresponding locations.

The wiring is slightly more involved if you decide to upgrade to a spring loaded 510 connector. But don’t worry, I have made another video dedicated to this topic as well. The title of that video is “MOD TIPS #03 – Fat Daddy vs Varitube Spring Loaded 510 Connector”.

Let’s Put it All Together!

Box Mod CompleteSince you have all the individual parts fully wired already. All that is left to do is connect everything together.

Make sure that you follow the above video for full details and the final wiring. Please refer the provided wiring diagram as well.

Once you have everything successfully soldered together. We can now try our new unregulated box mod!

Please remember that this box mod is wired in parallel. This means that you MUST place both 18650 batteries in an upright position. Both positives need to face up when placed inside the sled.

Final Thoughts:

You should now have an awesome box mod that you created yourself. Give yourself a pat on the back and show-off to all your friends!

But like all box mods, there are multiple ways to wire your project. The way that I showed you in this video is what I believe to be the easiest and provides the most options. We were able to include several safety features into this box mod that you may not find in other diagrams. Of course, feel free to use any wiring diagram that you feel comfortable with.

Overall, this is a very simple and basic unregulated box mod and would be the perfect project for the first-time modder.

As mentioned earlier, I do carry fully complete DIY Box Mod Kits on this site. You can see them at www.Shop.FindMyVapes.com

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  1. A question about the fuses you are using. The ones you linked have a HOLD current of 15 amps, and according to Mouser (Part #: 650-MHP-TA15-9-77) the TRIP current is 30 amps. Its my understanding that the fuses won’t activate until it hits the trip current, and will continue to act as a resistor as long as the current flowing through is at or above the hold current rating. Therefore, having two of these would give this box a 60A limit not a 30A limit. I am no expert in these things, so my question to you is: are we using these in such away such that they will trip at 15A? Thanks for this tutorial its pretty awesome.

    • Fred since this is a parallel mod, what will happen if you accidentally inserted one of the batteries in reverse making it series? Is that where the fuse will help?

  2. I’ve followed these instructions and ran into a problem. The mod was only discharging one battery, so I took things apart and found one of the fuses had broken, replaced both fuses and reassembled but now it’s only draining the other battery compartment. I’m considering removing this fuse assembly entirely, does this sound like a good idea? Lowest coil build I use is .4 ohms so I’m really not pushing any boundaries. Could there be any other root cause?

    • You are most likely damaging one of the fuses during install. You can safely remove/bypass the fuse as it is not mandatory. Just be aware of your battery limits as you mentioned.

  3. Can I use the IRF540 Mosfet on the mods?

  4. I have a question about the wiring schematic that you have for the unregulated box mod , does red denote 16 gauge wire and black 20 gauge ?

  5. Can you use any coil/tank with this?

  6. hello , i’ve done for my diy .. i just used single coil build but the firing goes slow .. can you gve me any solution for this ? mearelmy@rocketmail.com

  7. Can I just solder the 16 to the 20 gauge wire together and bypass the fuses..

  8. I used SSF1010 instead of BRF3034….. But MOSFET doesn’t turn on…. What can be the reason….?

  9. how would i wire a voltmeter into this configuration?

  10. I have an IRL540N mosfet, 30A 100V. Will this work?

  11. what is the wattage out out i dont get it lol

  12. If i will be using a single 18650 batt will this set up still be ok or should i have a different set up? Thanks in advance.

  13. sir can i use any kind of mosfet? please suggest any kind of mosfet that best for vaping
    thank you !

  14. can you add more batteries in this guide i’m planning to make it a 4 batt box mod

  15. I have a noisy cricket mod.. can I use kangertech tank mini on it? Please help me

  16. Hello! Why do we using fuses and resistors on on/off button? What if we dont use any of them?

  17. What Will said what is the wattage output for this box?