Higher current draw at lower voltage

Discussion in 'Batteries' started by X-Calibre786, 30/9/20.

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  1. X-Calibre786

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    Based on the discussion in this thread, it occurred to me that I may have inadvertently been doing something dangerous.

    Regulated mods draw lower current from the battery when the battery voltage is higher and higher current when the voltage is lower. So when a battery is fully charged at 4.2v, the mod would draw less current from the battery than it would if the battery was close to discharged at say 3.4v.

    The danger, in my opinion, comes in where a person may have a build, especially on a single battery mod, that draws close to the maximum current that the battery can manage safely. You may be safe when your battery is fully charged, as the current draw is lower, but as the battery gets discharged and the voltage drops, the mod would draw a higher current, and could possibly exceed the battery's rated CDR.

    At the very least, this could lead to the battery being damaged so that it doesn't last as long as it should in terms of charge/discharge cycles.

    This should not be a concern with unregulated mods as the power drops along with the voltage and so the current draw remains the same depending on the build you have in your atomiser.
     
  2. Dela Rey Steyn

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  3. Stranger

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    Dead right, if the device, which will include a regulated mod or semi mech has an over discharge function this will kick in and stop your device from firing. It is fully mechanical devices that you need to worry about. I previously used an example of the Sanyo 21700 B battery that only allows for a 15 amp Continuous Discharge Rate.

    Mooch rates the 30Q at also 15 amps and classifies it as high capacity as opposed to high drain, you are actually better off with 25R's in a mech as the amp rating is 25.
     
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  4. Resistance

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    We urge new vapers to not start with a mech for reasons you have noted and other reasons not in your post.
    And your concern is noted.
     
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  5. Intuthu Kagesi

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    This shouldn't be a problem as the current would drop proportionately to the voltage drop, assuming a fixed load, (I=V/R), under normal circumstances. In the case of a regulated mod ... I opened up a Vaporesso Gen S and did a few measurements. Their control of the PCM signal is done via two feedback mechanisms; The voltage available at the 510 connector, and; The voltage across a low value fuseable resistor, (as a current measurement), and any battery sag is dealt with by increasing the duty cycle to provide a safe, stable output at the 510 connector.

    This said, and in spite of the aforementioned safety / feedback mechanisms ... I would highly recommend that ALL builds are checked thoroughly before attaching them to any mod, regulated or not.
     
  6. Stranger

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    I agree, I was very afraid of mechs until such point as I got to an understanding of how unsafe they could be. Now I build on a regulated mod before I even think of putting it on a mech. I think the biggest danger would be with an unregulated squonk device. They look like you can just stuff a battery in there and vape away.
     
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  7. Intuthu Kagesi

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    Nothing wrong with some healthy respect Stranger ...
    After watching the arc welding happening on my mech, along with sensibly examining the pathetic excuse for battery terminals ... I no longer squonk, preferring to manually drip with a regulated mod underneath when testing / tasting juice;)
    IMG_20201001_092435.jpg
     
  8. Stranger

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    [​IMG]

    My Crea is not too bad as long as you set the pin correctly, but even then you have to watch your build. Anything below .2 on my Recurve dual creates massive heat.
     
  9. Dela Rey Steyn

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    Mechs are fun and safe as long as you adhere to Ohm's law. Your battery's specs should ALWAYS govern your build. The raw power through a mech is something I enjoy thoroughly. I have had plenty ( and I mean PLENTY, more than what SWAMBO would ever know of) mech squonkers and have never had an issue with a single one.
     
  10. Intuthu Kagesi

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    You're so right about watching your coil resistance carefully ... That's the only thing between a good vape and a bomb :eek:
    I do like your mech ... particularly the battery connectors, and "hidden connectors" ... unlike my "short circuits waiting for a time to happen ... you also have one of them "arc welder" switches tho' o_O
     
  11. Dela Rey Steyn

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    just get some dielectric grease for your switch contacts
    https://za.rs-online.com/web/p/cont...ksHRXMk_wnRnguUqRbRoCy64QAvD_BwE&gclsrc=aw.ds
     
  12. Stranger

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    You mean you were smart enough never to use one of those ultafire 3.7 V 5000 mah batts from the china store :facepalm:
     
  13. Dela Rey Steyn

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    Research is your friend, and Google (as long as you have data) is free!
     
  14. Intuthu Kagesi

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    I don't trust any unprotected Lithium cells, branded or otherwise, (having been burnt in the past :facepalm:), and would seriously suggest that everyone check their cells internal resistance from time to time, certainly in multiple cell mods so that you can balance, and marry them perfectly, whilst keeping an eye on their lifespan ;)
     
  15. Intuthu Kagesi

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    ... and that's one of the reasons I'm here ... to learn from others experiences / mistakes ;)