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Measuring Voltage Drop on the 521 Plus Tab

Discussion in 'E-Cigarette Accessories Discussion' started by Methodius, Dec 3, 2017.

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  1. Methodius

    Methodius Full Member

    Jul 3, 2017
    Hi folks,

    I was wondering if anyone else has found this weird.

    I recently received the 521 Plus tab from Geekvape. Been using the included add-on voltage checker to test output voltage from a mech mod. In this case I'm using the Athena squonk mod from Geekvape, powered by a single LG HB6 (Pink) 18650 battery.

    Mod is screwed in to voltage checker, attached to the tab. I'm getting a reading of 4.12 V output. This is without an atty attached to the 510 center mount.

    Attaching an atomizer with a resistance of 0.15 ohm, I fire the mod directly and the tab records an output voltage under load of 2.4, 2.55, 2.61 V. I fired three times to get an average reading.

    Does a voltage drop under load of 1.6 V seem crazy high to anyone else out here? It got me wondering if there's something in the voltage checker that is adding to the load.

    So I decided to take out the copper plated alligator clips, attach them to the slots in the tab, and the mod + build itself. Bypassing the voltage checker, basically. I also wanted to see if the 521 Plus tab could be used effectively as a multi-meter.

    I have one clip attached to the positive metal contact inside the mod. The other is clipped on the negative post of the atomizer. Before firing, I am getting a reading of 3.97 V on my 18650.

    I test fire three times and get the following results: 3.55, 3.52, 3.4 V. Average of 3.49 V.

    I read that as a voltage drop under load of 0.48 V on average. This also feels more consistent with the performance of the Athena generally.

    I'm wondering what is correct here. Could it be that the voltage checker is exaggerating the true voltage drop under load? Also that the 521 Plus tab can be kinda hacked to work as a multi-meter?

    Thanks in advance for any help. I checked a bunch of reviews but no one touched on this issue, or tried connecting the clips directly to a build to test drop this way around.
  2. Methodius

    Methodius Full Member

    Jul 3, 2017
    nobody wants to bite? or have I just posted in the wrong sub-forum?
  3. stols001

    stols001 Mistress of the Dark Nicotinic Arts Verified Member

    Supporting member
    May 30, 2017
    Tucson, AZ
    I'm always happy to bite, but you are asking questions way above my comfort level. Good luck!

    • Like Like x 1
  4. Methodius

    Methodius Full Member

    Jul 3, 2017
    Above mine too! A couple of reviewers picked up on it, but no one really troubleshooted it as far as I saw.
    • Like Like x 1
  5. zoiDman

    zoiDman My -0^10 = Nothing at All* ECF Veteran

    Supporting member
    Apr 16, 2010
    I'll Bite.

    A 1.6v Drop in Voltage does sound Crazy High to Me.
    • Like Like x 2
  6. Methodius

    Methodius Full Member

    Jul 3, 2017
    I'll try to post some pictures later tonight to illustrate all this.
    • Like Like x 1
  7. Methodius

    Methodius Full Member

    Jul 3, 2017
    Apologies in advance for the sh!tty quality of the pics. It's hard to fire a mod, hold positive and negative leads and press the camera button all at once!

    Anyway, here goes nothing:

    #1 - voltage checker reading battery voltage output correctly. 3.97 V.

    #2 - voltage checker reading coil resistance correctly. 0.15 ohm.

    #3 - pulse firing, voltage output under load of 2.83 V. Bear in mind the 521 plus tab is a bit sluggish in displaying info, so these numbers fluctuate a bit.

    #4 - pulse firing, voltage output under load of 2.7 V.

    #5 - pulse firing, voltage output under load of 2.77 V.

    #6 - alligator clips reading battery output voltage correctly. 3.88 V.

    #7 - alligator clips rigged up to the positive and negative contacts inside the mod, reading output voltage consistently. 3.87 V.


    #8 - alligator clips rigged up to the positive contact of the mod and negative post of the atomizer. voltage output is still consistent at 3.89 V.

    #9 - pulsing the coils with the leads in the same configuration gives a voltage output reading under load of 3.35 V.

    The results are slightly different from what I described in my original post, but the pictures should give you an idea of what I'm talking about. Voltage drop with the voltage checker attached was 1.21 V. Take the voltage checker away, do it with the alligator clips, and you get voltage drop of 0.54 V.

    What do you guys think? If any part of my methodology is flawed, please god please, let me know!

    I would add that trying to rig up some flimsy alligator clips to the positive and negative posts of the atomizer is a pretty bad idea. Not only do you risk shorting out your battery and melting the plastic housing of the clips themselves, but the positive post is damned hard to get to without making contact with anything negative on the atty. That's why I went for the positive contact on the mod.

    My tentative conclusion at this stage would just be: the voltage checker is great for finding out your battery's output voltage, but forget it when it comes to voltage drop. The figures are out of wack, and I don't quite understand why.

    If anyone can shed more light on this subject, or their own experience, I'd be grateful!


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