Question about voltage drop

Discussion in 'Unregulated (Mechanical) Mods' started by Chillaxman, Oct 22, 2017.

  1. Chillaxman

    Chillaxman New Member

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    Hello all. Just a question about voltage drop, if the voltage of my battery is at 3.8v and the voltage drops it to 3.3v~3.5v so 0.5~0.3 difference, do I need to charge my battery since 3.7v is where I'm supposed to be charging at? Should I just wait until the voltage of my battery hits 3.7v while ignoring voltage drop which would bring it down to 3.2v~3.4v?
     
  2. Carambrda

    Carambrda Gold Contributor

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    You should recharge your battery if the resting voltage (the voltage of the battery measured after a 30 second resting period) reaches down to 3.0 volts or if your regulated mod no longer receives enough volts from your battery for the mod to be able to keep up the vape performance you want from the mod... whichever occurs first. Most regulated mods cut off at a resting voltage of 3.2 volts. On a regulated mod, amps drawn from the battery by the mod are increased by the mod as the resting voltage of the battery declines. Most regulated mods are limited as for how many amps they are capable to draw from the battery. So, depending on the wattage you vape, the amp limit of the mod may be reached sooner than the aforementioned 3.2 volt cut-off, and, when this amp limit is reached, as a result the mod will automatically lower the power output─causing degraded vape performance.

    Discharging a battery all the way down to 2.5 volts (resting voltage) only once or twice on accident does not cause a lot of extra wear and tear on the battery, but should still be avoided nevertheless. NEVER (!) let the resting voltage reach below 2.0 volts.

    The resting voltage is not the same as the voltage your mod receives from your battery whilst you press the fire button. This difference in voltage is called voltage sag, and, how big this voltage sag will be will depend on a whole plethora of variables... for example, it will depend on how many amps are being drawn from the battery.
     
    Chillaxman and So619Cal like this.
  3. Chillaxman

    Chillaxman New Member

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    Thank you for your reply and info! Well I wasnt really talking about regulated mods, sorry that I didnt specify that I was talking unregulated m3ch mod. I'm able to check the voltage of my battery with a battery tester and voltage checker for voltage drop, so I was wondering if the voltage of my battery at 3.8v and a voltage drop that would read 3.3v~3.5v means I have to charge it or do I wait for the battery to reach at 3.7v and charge even though the voltage drop reaches at 3.2v~3.4v with 3.7v.
     
  4. merememories

    merememories New Member

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    i am using a 5a sony which has a sag of 0.5, I would recharge the battery once it hits 3.7. I don't really measure it I could tell by the heat of the vape when I need to change.
     
  5. Carambrda

    Carambrda Gold Contributor

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    Yes, with a single VTC5A in any one of my single 18650 tube mechs the vapor production is pretty much gone completely at 3.5 volts resting voltage. I usually stop somewhere between 3.8 and 3.75 volts resting voltage because that's where I find that the vape starts to severely lack any kind of punch or liveliness with a .1 - .11 ohm dual coil build.
     
  6. merememories

    merememories New Member

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    Dont you think you are abusing your cell with 0.1 ohm ?
     
  7. Carambrda

    Carambrda Gold Contributor

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    You're vaping on just a single battery expecting great vape performance so yes, of course you're abusing the battery. But not excessively so, at least not unless you start chain vaping immediately when the VTC5A battery is still fully charged (or close). As the battery gets discharged one step on every pull, the resting voltage of the battery declines, and, due to Ohm's law, the amps you draw from the battery will also decline accordingly so... you have to understand it's all about duty cycles. With such a coil build you don't hold the button down for that much longer than 1 second if the battery is fully charged. After every pull you let the battery rest... give it time to recover.

    The idea of finding the "sweet spot" here is to find out what's the best balance between not abusing the battery too much and still be able to get a satisfying vape out of it. Below .1 ohm you're not gaining much IMO... and above .11 ohms it hits too soft/relaxed for my taste... this is with a single VTC5A, but I vape the same way on a single iJoy 5-legged 20700 (not to be confused with the 4-legged version of it).
     
  8. Evileclipse

    Evileclipse New Member

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    All of the information you have given in this thread is so incredibly well put. I am very well versed in all things electrical, but have never seen it put so eloquently. With your permission I will use this in the future to help explain this to people?
     
  9. Carambrda

    Carambrda Gold Contributor

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    No problem, use it at your free will. But also be aware that .11 ohms on a single VTC5A is a couple of amps above Mooch's MVA rating for the VTC5A so, whatever you do don't let the fire button get pressed on accident for a long time... don't cook the battery... you want to cook something, then cook some juice instead, but don't cook it so hard you'll burn your tongue. lol
     

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