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Homemade Resistor Disc - Or How to Make Any 6v/7.2v Mod into ~5v Modularly

Discussion in 'Battery Mods' started by lunaras, Nov 29, 2009.

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  1. lunaras

    lunaras Senior Member ECF Veteran

    Sep 27, 2009
    This thread explains how to make any mod capable of running at 6v or 7.2v into 5v to hit the sweet spot, without making any modifications to the unit itself.

    This started as out when I got my Chuck a couple weeks ago. The 3.7v using an 18650 @3000 mah was great and so much more consistent than using my Blu. I decided to try HV vaping using 2x LiFePo4 16350 bats and when I did I found, the flavor was incredibly burnt and tasted awful. I tinkered around a bit and found that the bats were running 3.95v off the charger and so I was getting almost 8v through my atty. After letting them sit for a while, they dropped to 3.3v like they should be at full charge and I tried again. The experience was much better, but still a bit harsh, so I set out to find an easy way to drop the voltage a bit without having to modify my Chuck directly.

    I found it.

    Parts list:

    • A well ventilated area to work in
    • Liquid Electrical Tape (I found mine at Wal-Mart, in the automotive wiring area)
    • Graphite Lock Lubricant (again at Wal-Mart, at the key making counter)
    • A washer with the same or smaller inside diameter as the battery tube of you mod of choice
    • Wax paper to work on
    • A disposable container for mixing
    • A disposable mixing stick, such as a toothpick
    • Measuring spoons (optional)
    Construction steps:

    1. Spread out enough wax paper that you can comfortably work.
    2. Place your washer on wax paper.
    3. Place about 1/2 tsp. of liquid electrical tape into your disposable container.
    4. Add an equal amount of graphite to the container. This will take some experimentation to achieve the desired results; more graphite gives less resistance, but also makes the mixture more brittle when dry.
    5. Mix thoroughly using toothpick. This gives you a homemade version of the commercial product "wire glue". This product may work for this purpose as well, but you would still have to add graphite to change its resistance.
    6. Take your mixture and fill in the hole of the washer. Make sure it is completely filled with no air bubbles and is as smooth as possible. You can use another piece of wax paper and press on it some to help smooth and even it out (don't use your fingers, liquid tape is pretty hard to get off).
    7. Wait until it is some what dried, usually less than an hour, but depends on the graphite content.
    8. Prop the washer up on something like a couple toothpicks to allow air flow on both sides. This significantly speeds up the drying time.
    9. Allow to fully dry.
    10. Remove your resistor disc from the center of the washer.
    11. Done!
    Now, this ratio of liquid tape to graphite is going to vary depending on your resistance needs, if you need more resistance, lower the graphite content, if you need less resistance, add more graphite. I have successfully used up to about 1 part liquid tape to 3 parts graphite, but the end product is very brittle.

    The disc I made using the above recipe reads about 10 ohms on my multimeter from one flat surface to the other, exactly opposite each other. Now this sounds like a lot, but the disc is still somewhat flexible and when this disc is compressed by the batteries and spring, the carbon particles are pressed closer together and the resistance drops. This gives me a vape right around 5.5v (unloaded) when my batteries are at 6.6v.

    Drop your batteries and the disc in the tube. Order doesn't really matter since the resistance from the edge of the disc to the center, where the battery contacts is hundreds, if not thousands of ohms. If you're worried about leaking current in this manner, take some of your liquid electrical tape and coat the edges of the disc, leaving the center on both sides clear for the contacts and let dry according to the directions.

    I'll post some pics tomorrow of the process and end result.

  2. lunaras

    lunaras Senior Member ECF Veteran

    Sep 27, 2009
    Reserved for pics.
  3. doots

    doots Vaping Master Verified Member ECF Veteran

    Aug 22, 2009
    lol. how did you ever come up with this? Does it really lower to about 5v output?? pretty cool.

    How big of hole in the center does it have to be? does it matter?
  4. Wireguy

    Wireguy Super Member ECF Veteran

    Oct 24, 2009
    Birmingham Al
    Sounds good. I'll be interested in how it stands up over time. Not like you couldn't make them a dozen at a time.:D

    I'll definitely play with this after I finish the 3 mods I'm working on. I never liked the regulators etc.

  5. lunaras

    lunaras Senior Member ECF Veteran

    Sep 27, 2009
    Yep, mine makes 6v down to 5.0-5.4v depending on the charge level. Depending on the thickness of the disc you make and the amount of graphite, you can make one that makes 7.2 (2x 3.6v bats) down to 5v. It just may take a little trial and error.
  6. Wireguy

    Wireguy Super Member ECF Veteran

    Oct 24, 2009
    Birmingham Al
    It was discussed in another thread. Or he could have come up with it on his own.

    I guess I'm posting for the heck of it.:)
  7. doots

    doots Vaping Master Verified Member ECF Veteran

    Aug 22, 2009
    Very nice idea for us HV Users!
  8. lunaras

    lunaras Senior Member ECF Veteran

    Sep 27, 2009
    I agree, my experience with regulators and transistros didn't work well. This disc still wastes energy like a resistor, but so far it has no problems overheating or anything like that after 3 days of heavy vaping, so I'm hopeful that it'll last a while.
  9. lunaras

    lunaras Senior Member ECF Veteran

    Sep 27, 2009
    I was discussing wire glue with another user on a thread and the high resistance of it gave me this idea and I finally got around to building it. If it came from another thread, then I haven't seen it and I apologize to the poster for stealing the idea. :)
  10. Some Guy

    Some Guy Senior Member ECF Veteran

    Jul 17, 2009
    Ct. USA
    I thinks this is a good idea. I toyed with the idea of mixing conductive epoxy with regular epoxy to get the desired resistance.
    I like how your little disc could just be dropped under the spring or above it and not take up any space hardly at all. And no soldering on a metal housing type mod. Good way to save space.
  11. Wireguy

    Wireguy Super Member ECF Veteran

    Oct 24, 2009
    Birmingham Al
    Yea, I've built power supplies and power regulators with them but they get to hot for my liking for this
    application. Rather inelegant also.

    I was thinking that this may not get too hot because it has the entire system to use as a heat sink unlike the regulator. As long as the batteries don't get to hot.
  12. lunaras

    lunaras Senior Member ECF Veteran

    Sep 27, 2009
    I used a washer that had a inside diameter just slightly smaller than the ID of my Chuck, about .75", so the disc would fit easily down the tube. The thickness and graphite content are the main constituents in how much resistance disc ends up having, the diameter of the disc is pretty much determined by the size available in the mod.

    I have also tried this with a nylon washer that had a hole about 3/16", which was the perfect match to the button on my battery. In this case, I left the washer surrounding the resistor disc attached and trimmed the washer to fit down the tube since its diameter was too wide. I didn't have much success getting a good contact with this since the mixture shrinks a bit when drying, and left the top side with a bit of a depression.

    I don't recommend using the nylon washer right now for those reasons, but I may find some way to do it well and if so, I'll post it here.
  13. smonomo

    smonomo Moved On ECF Veteran

    Oct 4, 2009
    USA, Northeast.
    Thanks lunaras,

    Definitely gonna play around with this.
  14. Jason365

    Jason365 Super Member ECF Veteran

    Aug 18, 2009
    Wow that sounds great. If this really works, I will be making me one. I will keep cheking back here to find any updates, and of course Pics or it diddnt happen.:D
  15. HippyGirl

    HippyGirl Super Member ECF Veteran

    Oct 30, 2009
    OK, stooooopid question...

    Can this be adapted for a nicostick somehow?
  16. NickJuice

    NickJuice Moved On

    Aug 22, 2009
    is that 5v's loaded or unloaded voltage? If unloaded...what does it do loaded? Loaded voltage is the Actual Voltage you are vaping at...
  17. lunaras

    lunaras Senior Member ECF Veteran

    Sep 27, 2009
    Sorry about no pics yet, I can't find the camera atm and haven't had time to do a thorough search. My wife stashes it somewhere different after every time she uses it and then can never remember where she put it.:p Hopefully I can find it tonight and get some posted.

    I'm assuming you are referring to a nicostick with two cells in it to give 6.0v or 7.2v since the original nicostick just used one 3.7v cell and pairing a resistor with this would be rather pointless. Theoretically, you should be able to, as long as you have enough room to put a 1-2mm thick disc between the batteries or one of the batteries and a contact. I know that in some boxes the spring ends up being really tightly compressed, and in this case you just may not have enough room.

    You will have to find a washer that has an ID close to the same diameter as your battery, or you could use a bigger one and cut the disc down to size. Heck, given that a nicostick boxy shaped, you could use a squareish/rectangularish one instead, as long as it fits.

    This is the unloaded voltage, just like all other 5v mods I've seen. I don't have the parts yet to make a way to test the load voltage on a mod like the Chuck, but I'm sure that the voltage drops to something like 4.5v under load, again, just like every other 5v mod out there. Once I rig up something to test the load voltage (may be a while before I get time and/or parts), I'll post the results.
  18. smonomo

    smonomo Moved On ECF Veteran

    Oct 4, 2009
    USA, Northeast.
    I tried this a few times, but getting the mix right is dead tricky, I either have too much or too little resistance.
  19. whiskywill

    whiskywill Senior Member ECF Veteran

    Oct 10, 2009
    sothern cali yucaipa
    would love to see a pic to know what im going for
  20. eclypse

    eclypse Moved On

    Sep 9, 2009
    Macomb MI
    Any updates of pics of the mod yet?
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