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Regulated Mods - Batteries, Resistance Explained

Discussion in 'Help I have questions!' started by KingPin!, Mar 24, 2017.

  1. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Hi All,
    Seems other than "help my mod isn't firing" the most asked question seems to be "what battery should I use when trying to use X resistence or X wattage on my regulated mod"

    There are loads of good reference materials out there which I'll post links for after this initial post (after much research myself)

    Note: This post is not intended as "be all and end all" about battery safety so please research other safety aspects seperately (for instance mooch's blog - link posted below), it's about choosing the correct battery and resistence build with an explaination on how each is working on a regulated mod

    Note2: I've sourced the information in this thread from multiple sources and stitched it together with working examples in one place for easy reading - I'm not professing to be an authority when it comes to batteries I would refer you to mooch in this regard. I have given credit with associated links to people I sourced material from... a great video with a wide range of material to watch is:



    So onto the thread itself ....I thought it would be a good idea to list out the mods or common chips used in mods and the current drain at max settings you'll need to cover. Of course with a caveat that I advise you to double check and carry out your own research

    First to dispel some myths though ...regulated mods work on a 2 circuit basis, as such you are interested in the "input" information which believe it or not has nothing to do with the resistence of your coil when trying to determine battery safety. This input circuit is between the battery and the regulator (or chip), rather than "output" circuit between the regulator and the atty (coil) this is in direct contrast to mechanical mods where resistence is of upmost importance as the battery and atty are shared in 1 single circuit.

    In terms of battery safety unlike mechanical mods, regulated mods draw more current as the battery voltage decreases to meet the wattage (VW mods) or voltage (VV mods) demands you set on the mod. Once these demands are no longer met the mod will display the low battery message and refuse to fire (in most case where there is low voltage protection built in).... it's this bit we are interested in as the max current drain will be where this happens so in terms of safety you need to be sure you use batteries that can cover this.

    There are other things impacting the input information i.e. battery sag, where a batteries internal resistence needs to be taken into consideration I.e a battery at 3.2v might only delivery 2.8v-3v due to this sag (see reference material 8)

    Also chip efficiency is important to the input as the chip takes some additional current on top of your setting to power the chip itself i.e a 90% efficiency means it needs an additional 10% power to function

    You can calculate this input information yourself It's an extension of Ohms law I = P / V

    If you list everything out you need to know:

    Mods Max Wattage (A)
    No. Batteries in the Mod (B)
    Low Voltage Cut off (C)
    Sag buffer% (D)
    Chip Efficiency% (E)

    (N.B some of these we can assume if you're not sure but does means the calculation is more of an approximation so extend some of the figures to more extremes)

    Put another way if you want to manually calculate this:

    1) Max wattage of mod / no batteries in mod = max wattage per battery

    2) low voltage cut off - (sag buffer%) / no of batteries = low voltage per battery

    3) max wattage per battery / low voltage per battery /chip efficiency = Current drain

    Note: Dividing by the number of batteries ignores whether a mod is wired in series or parralel hence why it's done

    For example

    1) The Smok HPriv is 220w,
    2) uses 2 batteries,
    3) has a low voltage cut off of 6.4v
    4) but I'll put 5.6v (with an assumed 12% sag buffer),
    5) and since I don't know the chip efficiency I'll assume it's 90% to err on the side of caution....So this is

    1) 220 / 2 = 110 max wattage per battery
    2) 6.4 - (6.4/100*12) /2 = 2.8 low voltage per battery
    3) 110 /2.8 / 0.9 = 43.65amps drain per battery

    Holy shit 43.65amps per battery! Yep ....now the Smok chip will kick in and limit current draw before this level (bucking and/or boosting) and deliver what it can in pulses but that's a whole load of drain and stress on the chip to cover without the right battery!... problem is you try and find a 18650 with this much CDR! (And is another reason a lot of people say that 220w is a load of bollocks on a dual battery mod... not unless it's in microsecond bursts youre more likely to get something closer to 167w)
    All this aside and knowing I don't vape above 110w on my device I can change that 220 to 110 which now gives me 21.82 amps per battery drain much more acceptable right!

    Knowing this information allows you to purchase the right battery with the appropriate Continious Discharge Rating (CDR) to cover the amps like the above example. At 110 wattage I might want something like the Sony VTC5A with a CDR of 25, and may even choose this battery when vaping at lower wattages on that mod just in case I push it one day, or to place less stain the mods chip and battery.
    It's always better to have additional CDR in reserve where you can and vape within safe wattage limits

    Reference material:
    1)http://blog.thevaporist.org/2015/12/29/regulated-mods/
    2) https://www.e-cigarette-forum.com/f...ngs-picking-a-safe-battery-to-vape-with.7447/
    3)https://www.reddit.com/r/electronic...you_dont_calculate_current_draw_on_regulated/
    4) https://www.e-cigarette-forum.com/f...attery-current-draw-for-a-regulated-mod.7532/
    5) https://www.planetofthevapes.co.uk/...lating-amp-load-using-a-regulated-mod.128294/
    6) http://vapingunderground.com/blogs/for-the-new-and-inexperenced-vapor.16/
    7)http://vapingunderground.com/threads/anthony-vapes-presents-vaping-safety-101.300140/
    8) https://www.e-cigarette-forum.com/forum/blog-entry/what-is-battery-internal-resistance.7569/

    Acknowledgements for our members who have helped me form this thread knowledge they have posted/shared with associated links above
    @gbalkam
    @conanthewarrior
    @Mooch
    @f1r3b1rd
    @SirRichardRear

    Mooch also runs a blog with some excellent material including other aspects of battery safety well worth taking the time to read this
    https://www.e-cigarette-forum.com/forum/blogs/mooch.256958/

    So without further ado (all are 18650 devices at max wattage)

    All devices at max settings:

    Hohm Wrecker 151w (98.8% efficiency, 12% sag)
    =27.29 amps per battery

    Hohm Wrecker G2 171w (98.8% efficiency, 12% sag)
    =30.91 amps per battery

    Hohm Wrecker Slice 101w (assumed 90% efficiency, 12% sag)
    =40.08 amps per battery (takes single 26650 battery)

    Smok (Assumed chip efficiency at 90% and sag at 12% accross all of the below)
    HPriv 220w = 43.6 amps per battery
    Alien 220w = 43.6 amps per battery
    X cube Ultra 220w = 43.6 amps per battery
    X cube 160w = 31.75 amps per battery

    DNA 250 devices (97% efficiency, 12% sag)
    = 30.68 amps per battery

    DNA200 devices (97% efficiency, 12% sag)
    = 24.55 amps per battery

    DNA167/166 Devices (97% efficiency, 12% sag)
    167 = 30.74 amp per battery
    166 = 30.56 amps per battery

    DNA 75 devices (93% efficiency, 12% sag)
    = 28.8 amps per battery

    YiHi SX475J devices (92% efficiency, 12% sag)
    = 29.11 amps per battery

    YiHi SX550J devices (96% efficiency, 12% sag)
    = 37.2 amps per battery

    YiHi SX450J-BT devices (95% efficiency, 12% sag)
    = 37.59amps per battery

    YiHi SX350 J-V2 devices (93% efficiency, 12% sag)
    = 28.8 amps per battery

    YiHi SX350J devices (93/efficiency, 12% sag)
    = 23.04 amps per battery
     
    Last edited: Apr 8, 2017
  2. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    In my first post I talked about 2 circuits, focussing on what's happening between the battery and the mod (the input circuit). In this one I'll refer to the 2nd circuit between the mod and the atty (coil), or as its called the "output circuit"

    "Since we are looking at two separate circuits, you can never mix numbers from both sides of the regulator in your calculations. For instance: You cannot determine the current drained from the battery by measuring the resistance of the coil and the voltage of the battery. Using the resistance from one circuit, and the voltage from a different circuit, will result in a nonsensical answer. Nor can you determine the current going through the coil by determining the current from the battery".
    Source - http://www.steam-engine.org/batt.html


    With this in mind we need only know that the mod has the voltage and current available from the 1st circuit to do what it needs to do...when it can no longer perform it will display the low battery message in most cases
    For this second circuit we are interest in either the wattage or voltage as an output, also resistence in this second circuit does play a role, as to why though we need to come back to ohms law (but two variations depending on the type of mod you are using)

    1) for variable wattage mods (VW)

    We use V= [square root] of P x R

    Voltage (V)
    Wattage (P)
    Resistence (R)

    1) You know the wattage it's showing on the device in wattage mode
    2) You know the resistence of your coil

    Those wanting to venture down to super low ohm builds the good news is you can although there are a few things to take into consideration:

    A) you are limited by your chips settings, take my HPriv example again - let's go for max wattage just for the hell of it 220w. My mod will allow a coil resistence down to 0.1ohm (anything lower my mod will display a warning message to me and won't fire)

    B) other mods have setting like maximum wattage output or maximum amps output which limits how far the mod can be pushed so look your mods specs up to know what values you can use.

    C) if using more than one battery how is the Mod wired Series or Parallel?

    Mods Connecting in Series
    When connecting your batteries in Series you are doubling the voltage while maintaining the same capacity rating (amp hours) and CDR value of one battery. Example below

    [​IMG]
    so two 18650 batteries will have a combined total of 8.4v when fully charged and 6.4 (5.6v with sag when it's time to change them) which is handy for this second post and is why most regulated mods are series wired ....let stay focussed on the depleted number 5.6v

    Mods Connecting in Parallel
    When connecting in Parallel you are in theory doubling the capacity (amp hours) and CDR while maintaining the voltage of one of the individual batteries. Now since not everything is exactly equal for safety purposes take 50% CDR away from one of the batteries to err on the side of caution (For example you have two batteries, each have a CDR of 20... minus 50% from one gives you a CDR of 30)

    [​IMG]

    so two 18650 batteries have 4.2v when fully charged and 3.2v (2.8v with sag) when it's time to change them. (but these have 1.5 times the CDR which handy for the first post ....let's stay focussed on the depleted number 2.8v

    Important notes: Don't use two different chemistries when connecting batteries.

    Always use married batteries I.e bought together always charged and used together, otherwise voltages will be different, but more importantly the charge rates will be different and the capacities may be different, thus resulting in a shortened life span.

    Match capacities. When connecting batteries in a pack you should try to match the capacities as much as possible to avoid discharging one battery quicker than another. A pack operates at a combined voltage so your one cell that discharges quicker will likely discharge deeper than it may be able to recover.

    I won't get into what's better ...suffice to say they achieve the same things in different ways

    Why do these things matter? Well if you want to understand how to optimise the life of your battery before changing them and avoiding that low battery message earlier than we should we can now find out how

    Ok HPriv example @220w, Resistance of 0.1

    Square root of 220 X 0.1 = 4.69volts
    - this is ok right jobs a gooden my mod is wired in series so has 6.4v to cover this when nearly empty (or 5.6v with 12% sag) except don't forget my first post on current draw!

    Lets now go for something most people advise 0.3 ohm resistence but trying to maintain our 220w

    Square root of 220 x 0.3 = 8.12v
    - dammit more than my mod can handle it simply cannot work at that wattage for long ...I'll take like 6 puffs and I'll get that damn message low battery even though my batteries still look charged

    Ever wondered why on the Smok beast tank the TF-T8 coil is resistence of 0.16ohms?

    Square root of 220 x 0.16 = 5.93volts
    This is right on the the threshold of low voltage cut off my 2 batteries in series can deliver at 220w (with sag) at near empty! Awesome right

    Well there you have it knowing this voltage output will allow you to target a desired coil resistence build between the upper and lower wattage setting you want to vape at, which will allow the full range of the battery before the low voltage cut off build into most regulated mods kicks in :) (do check if you mod has this feature first)

    So going back to my 110w I don't tend to go past and knowing my lowest resistence allowed in 0.1ohm

    Lowest threshold
    Square root of 110 x 0.1= 3.32volts

    Highest threshold
    Square root of 110 x 0.3 = 5.74 volts

    I now know to build my coils for a max wattage setting of 110w between 0.1 and 0.3! This will allow me to vape from fully charged all the way through to empty :)

    2) for variable voltage mods (VV)

    These devices need a different equation from ohms law as you have a diffent input

    P = V x V / R

    Wattage (P)
    Voltage (V)
    Resistence (R)

    This time you know only the voltage and resistence

    So unlike VW mods you can only see the voltage and turn it up or down as you go, but its a little more difficult to dial in for that perfect setting but you can get close!

    Let's take my VW example into consideration I want to vape at 110w how do I do that?

    A number of ways

    6v output with a 0.33 resistence

    6 x 6 / 0.33 = 109.09watts

    4.7v output with a 0.2 resistence

    4.7 x 4.7 / 0.2 = 110.45watts

    3.3v output with a 0.1 resistence

    3.3 x 3.3 / 0.1 = 108.9watts

    Now I know at these settings it will be at 110 watts turn it down to go lower or up for more

    As you can see both of these mod types achieve the same thing but in different ways ...and now you're equipped to select the right coil build and correct battery :)

    Please follow this link for Moochs recommended batteries (select the right one with the information you've ascertained above)

    https://www.e-cigarette-forum.com/forum/blog-entry/moochs-recommended-batteries.7593/

    If anyone wants Devices added to post 1 by all means call them out
     
    Last edited: May 6, 2017
  3. Carambrda

    Carambrda Silver Contributor

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    You should probably change "don't unnecessarily purchase that battery" to "know that battery might still be the better choice anyway after all because not only will I be safer, but also I will be causing less strain on that battery so as a result from this it might take longer before I will need to make another new battery purchase (and the closer I get to the CDR, the more significant this particular part of the story becomes)".
     
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  4. f1r3b1rd

    f1r3b1rd Phantom Pilot Staff Member Senior Moderator VU Donator Diamond Contributor Member For 2 Years

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    Great post!!!!! Thanks you for taking the time to put it together!

    Sent from my XT1650 using Tapatalk
     
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  5. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Done edited ;)
     
  6. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Thanks Firebird means a lot :) hey reckon we should sticky this one? Gonna add some more stuff to it about the other side of the circuit and parralell vs series mod wiring with a bit on ohms law as well
     
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  7. f1r3b1rd

    f1r3b1rd Phantom Pilot Staff Member Senior Moderator VU Donator Diamond Contributor Member For 2 Years

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    you haz been stickied
    thank you
     
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  8. kevinjp

    kevinjp Silver Contributor Member For 1 Year

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    Great post. Hohmtech Mods are popular here so maybe the G2 and Slice
     
    Last edited: Mar 25, 2017
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  9. Carambrda

    Carambrda Silver Contributor

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    Another thing you might want to add is that the vape performance of a regulated mod is also affected to some certain degree by how hard the battery hits so people should take this properly into account before they go ahead and purchase a 20 amp battery that costs like 3 cents per day less than a 25 amp battery because, again... you still forgot to add the fact that a CDR of 25 amps is safer than a CDR of only 20 amps, even if used at lower wattages, even if never going to be used at higher wattages, even though it's true the fact that using it at lower wattages will also add to the safety. Not wanting to nitpick or anything, but let me please repeat... the closer you get to the CDR, the more significant this particular part of the story becomes.
     
  10. Darth Omerta

    Darth Omerta Silver Contributor ECF Refugee

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    Very nice post @kingpin !!!!! Thanks for the work!
     
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  11. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Added ;)
     
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  12. Carambrda

    Carambrda Silver Contributor

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    And if the CDR is high enough for the battery to be safe, but not so high that it doesn't harm the vape performance of your regulated mod in any noticeable way, then the risk of going back to smoking will be higher as a result. Capisque? :)
     
  13. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Added a line although I expect members will read these replies as well ...you have articulated this point well
     
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  14. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Post 2 now added folks featuring circuit 2! :)
     
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  15. IMFire3605

    IMFire3605 Bronze Contributor Member For 1 Year ECF Refugee

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    Good read and excellent information. Little heavy on the Algebra side for most people, but people need to rethink their daily lives, never realising they use Algebra every day anyway but complain it is to hard :p
     
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  16. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Thanks IMF ... means a lot :) I know, I tried to do some working examples to lighten the load on the algebra but it is what it is I cant dumb it down further than that hehe
     
    Last edited: Mar 25, 2017
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  17. SirRichardRear

    SirRichardRear AKA Anthony Vapes on Youtube VU Donator Diamond Contributor Member For 1 Year Reviewer

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    Nice post @KingPin! very nicely done and thanks for taking the time to put it all together.
     
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  18. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Thanks buddy ;)
     
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  19. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Sorry mate I've added a link to your thread and given due acknowledgment to your good self as well ;)
     
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  20. SirRichardRear

    SirRichardRear AKA Anthony Vapes on Youtube VU Donator Diamond Contributor Member For 1 Year Reviewer

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    Not necessary but appreciated :)
    Thanks

    Sent from my SM-G935V using Tapatalk
     
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  21. Jonnystevenson

    Jonnystevenson New Member Unlisted Vendor

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    Huge knowledge is contributed here, Thanks @KingPin! for this great work :)
     
  22. Carambrda

    Carambrda Silver Contributor

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    While it is true the fact that the CDR doubles if connecting two batteries in parallel, in practice it just doesn't work that way because in terms of battery safety the total CDR becomes 15 percent less than double (that is, per none other than famous Mooch himself). So a battery with a CDR of 25 amps becomes 2 x 25 = 50 according to the theory, but in practice you subtract 15 percent from this, giving you a total of only 42.5 amps CDR instead of 50.

    Further, this topic creates the false impression that finding out which batteries to use is all there is to know about the safety of your batteries, when the reality is that there are a few additional key factors that you have to take into account (that is, also per none other than famous Mooch himself).
     
  23. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Share the links on this I'll take a read and happily edit my post if there is inaccurate information

    ...the intention of this post is not about general battery safety it's more about choosing the right battery and resistence to begin with so have added a note now at the top hope this clears that aspect up ;)

    @Carambrda :)
     
    Last edited: Apr 8, 2017
  24. Carambrda

    Carambrda Silver Contributor

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    About batteries connected in parallel,
    Code:
    https://youtu.be/KtMRuivHn68?t=3226
    Further, the whole point about battery safety is also to avoid confusion about it as much as possible. So for this reason, Mooch's standpoint is to just keep ALL the related info bundled in a single spot that's easy to find.
     
  25. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    I appreciate that hence the myriad of links I've added including Moochs blog which is a central repository of info in itself

    Reading back over your replies you have taken issue with this thread from the start ...I don't believe the information contained within here is inaccurate, as I've said I'm happy to edit something if it's wrong but I'm not going to keep entertaining other points you are making which is widening the focus of the thread ...I have added notes throughout iterating your comments, by all means add some links for further reading if you don't think the ones I've provided are of satisfaction to other forum members
     
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  26. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    There you go changed the title as well ....
     
  27. Carambrda

    Carambrda Silver Contributor

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    It's not about taking issue with this or any other thread. Instead, it's about vaping safe... which reflects on us all also due to the way other people look at those who vape, and besides... I'm only parroting Mooch because IMHO the guy can never be parroted enough (especially not with all the smear campaigns that keep going on about exploding vapes).
     
  28. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Fair enough I take your point...as I said I've added notes changed the thread title beyond that this thread informs people how regulated mods work and how they are different to mechanical mods which gives people the tools to make informed choices to the battery they might select and target build on the atty along with some working examples... it was never about the entirety of battery safety ..I feel I have edited much of the post to incoperate this aspect and led people over to mooch and other helpful posts for that aspect

    can we now agree to stay on topic?
     
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  29. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    I've incoperated the vid and updated the parallel section I've also put it to more of an extreme to minus off 50% rather than 15% better to do that just in case... thanks @Carambrda
     
    Last edited: Apr 8, 2017
  30. conanthewarrior

    conanthewarrior Gold Contributor Member For 2 Years

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    Fantastic guide here @KingPin! , it will definitely help people when they are unsure of amp load on a regulated mod.

    I still see many people worrying they are going over their batteries CDR, at say 0.15 and 80W because of the amp reading on the screen. They do not realise this is what is going to the atomiser, and not the input stage.

    For a fair time, I calculated wrongly using Ohm's law, assuming this was how to work out amp load on my batteries, as when someone new to vaping asks questions, they are told to learn and understand Ohm's law and battery safety, but no one mentions you don't use Ohm's law to calculate amp load on a regulated mod regarding batteries. So it is understandable why people get confused, and I have spoken to many people who flat out tell me I am wrong when I explain to them.
    After showing them the evidence and calculations though, it is like their whole world is flipped, which I can understand as when I found out I was quite annoyed I had been calculating completely wrong, and possibly putting myself in danger due to this.

    Also, thank you for mentioning me and sharing my link to my guide over at POTV's.

    Is this stickied? If not, I think it should be. It might be worth adding a TL: DR section for people who just want to get to the calculations, and explaining it is simply Watts/input battery cutoff= Amps. Then divide by 0.9 for efficiency.

    That is only meant to make the guide as clear and easy for people as possible, I think you have done a great job here :)
     
    Last edited: Apr 16, 2017
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  31. The Cromwell

    The Cromwell VU Donator Diamond Contributor Member For 1 Year

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    Resistance is futile.
     
  32. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Thanks matey this was the whole reason I created this in the first place I was getting frustrated with the whole you need to learn ohms law thing for mechanical mods before this I even advised incorrectly as well on regulated devices as this is what I was told up until this point ....you and SRR set me straight in another thread so did a whole bunch of digging for the content on this one with the aim to help everyone else :)

    Firebird kindly stickied it already
     
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  33. conanthewarrior

    conanthewarrior Gold Contributor Member For 2 Years

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    I made the one over at planet of the vapes for the same reason, so many people were asking and getting that reply, quite a few people were replying with the correct way, but many people were not, and it wasn't just new vapers.

    I also for a long time gave the same advice regarding Ohm's law, and really felt bad when I learned I had been told the wrong thing all along, and in turn had done the same myself. I can see why people still get it wrong now though, after all if you are told by lots more experienced vapers to learn Ohms law, you do so, and then assume this applies to what you are using. It was only when I really thought about it, and wondered how a mod put out more or less voltage than the actual batteries that I found out otherwise.

    It will definitely help people out, and I am glad it is now stickied :)
     
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  34. Ali Moorad

    Ali Moorad New Member

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    Wow! Great guide Kingpin! I must say... it's one of those things i probably need to read like 20 times before it starts making sense but i can see a lot of effort was put into it! Thanks man!
     
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  35. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Thanks matey and Yeah know the feeling lol I did post a link to firebirds blog in the first post has some great introduction content to ohms law etc have a read of that first might help visualise what I'm going on about a bit more (it's the 6th link)
     
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  36. Puff

    Puff Gold Contributor Member For 3 Years

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    Well I just got education on Batteries and such Thank You

    Sent from my LG-V930 using Tapatalk
     
  37. Jane808

    Jane808 New Member

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    peek peek;)
     
  38. Jonnystevenson

    Jonnystevenson New Member Unlisted Vendor

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    Ahhhhhhh. a lot of knowledge for beginners
     
  39. Jman1234

    Jman1234 New Member

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    This explains exactly the questions I began having when first learning about battery safety. Why are they making mods at 220 on two 18650s when you are straining them if you are putting out that wattage. Not to mention don't really need that much lol, but I guess that is subjective. Thank you for taking the time to put this together.
     
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  40. Vaping_MD_Student

    Vaping_MD_Student New Member

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    So I'm playing around with numbers just to solidify all the information in my head and then I got stuck at the low voltage part. All of the information I'm finding for the RX200 is that the cutoff is somewhere between 2.9 and 3.2V (2.9 in the manual and 3.2 anecdotal from forums). Is this the low voltage per battery or is this the number I should plug into the equation? The equation would give me 0.9V per battery assuming the same 0.12 sag buffer used in the first post.
     
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  41. Vaping_MD_Student

    Vaping_MD_Student New Member

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    And a secondary question (before I stop and watch the long ass video)... It seems to me that the first post is where you would find the amperage information and the second post is intended to find the voltage used? Here's why I ask: amperage can be directly determined from the equations in the first post and derived from the second post (using ohm's law). As far as battery safety is concerned, using the 2.9V value (for a larger safety margin) my calculations give me a max I=25.5A (200W max, 2.9V cutoff, 3 batteries, same assumed 90% efficiency and 12% lag). Now.. Moving forward to the second post, I'm wanting to vape a .14ohm build at 125W. Plugging these numbers in gives a voltage of 4.18V. Ohm's law then gives I=29.9A.

    So.. It's safe to say I'm confused somewhere. I've reread the initial posts a couple times and mentioned what I think I should be getting in the first paragraph. I guess I'm trying to make sure I'm correct in that I shouldn't be deriving amperage from the second circuit?
     
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  42. otto85

    otto85 Gold Contributor Member For 2 Years

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    Lets keep looking at the rx200 using 3 batteries in parrelal it only uses 4.2v which is 1 batteries votlage but using batteries with 2500mah it has access to 7500mah. In that case the voltage is always as a whole, now if you where using a device that runs in series with 2 batteries running 2500mah the voltage is 8.4v and 2500mah. Hope that answers your question


    Sent from my LG-LS997 using Tapatalk
     
    Last edited: Jun 29, 2017
  43. Vaping_MD_Student

    Vaping_MD_Student New Member

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    TL;DR - just questions, no fluff of thought process. I know I can be rather long winded.
    1) Single circuit (mech mod) batteries in series maintain mAh and CDR while increasing voltage at a rate of nV where n = # of batteries?
    2) If #1 is correct, in a two circuit system (regulated mods), does using lower voltage than possible change either the mAh or CDR values?
    3) Capacity (mAh) is, in general, the amount of battery life from fully charged to dead?
    4) A > CDR = boom?
    5) None of this answered my original question.

    _________________________________________________
    That actually leaves me more confused than I already was, which is generally a good thing for me. MOAR LEARNINGS! Please correct me if any of my base knowledge is incorrect in the rest of my post. Again, using the 3 battery RX200, in a single circuit system, the batteries in series would theoretically triple the voltage output while maintaining the mAh and CDR of a single battery. I'm using Samsung 25R batteries, so the voltage on the manufacturer sticker and Mooch's chart for CDR and mAh gives me an adjusted theoretical 11.1 V (3.7V x 3), 20A CDR, and 2500 mAh to play with. Ignoring that I'm using a regulated mod, is that correct so far?

    Quickly before I move forward, I also want to make sure I am comprehending capacity (mAh). That can be viewed as battery life from full charge to dead?

    Assuming the above is correct, let's talk regulated mods. I'm currently vaping on a 0.36ohm build at 100W, which is showing me 6.00V on the mod screen. According to the circuit 2 math in the original @KingPin! posts, that is correct. Because the batteries are in series, that is well within my voltage limit of 11.1V (or the safer 7.4V using [V+2*0.5V]). So, since I'm dialing back the voltage used from the max possible voltage, something else is changing. From your response, it seems that the resulting voltage change (due to wattage change) causes the resulting mAh to increase? Is that also correct?

    I have a couple more questions to clarify my understanding of the concepts in general.
    a) amperage>CDR=boom?
    b) are there any other relationships that I should be worried about as far as fatal errors for the battery or is that the main one?

    All of the above aside, I wasn't asking about mAh as much as I was trying to clarify my understanding of both circuits described in the original posts in regards to amperage and how that will affect my batteries. I'm not complaining, though, since that caused me to want to clarify my understanding and ask further questions.

    As much as I'm trying to stay away from mech mods, this is why they're getting more and more attractive to me. They seem to be much more simple. I wish I had actually paid attention and learned this shit in undergrad physics....
     
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  44. otto85

    otto85 Gold Contributor Member For 2 Years

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    1.correct
    2.incorrect battery capacity and max output cannot be altered
    3.mah is the battery capacity as where cdr is the amount of energy the battery can constantly expell
    4.possible. Theres many variables when dealing with batteries amd battery safety.
    1.ohms
    2.amps
    3.wattage used
    4.length of power use. Using ohms law to find your max wattage at lowest possible ohm is completely safe, now lets say someone makes coils using alot of wire that requires much higher wattage, the use of a preheat mode using higher wattage for a short amount of time (.5-1sec) is perfectly safe as that would fall under a pulse rating which is much higher then the constant discharge rating. Higher wattage obviously means higher voltage so vaping at a higher wattage then what ohms law calculates for your ohms is risky and thats why some mods have implemented the preheat mode. I did get series and parralel mixed up in my waking up for the morning lol my bad the rx200 is parralel NOT series. Series is where all the batteries face the same direction as where parralel all the batteries are facing in opposite staggered direction

    Sent from my LG-LS997 using Tapatalk
     
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  45. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Per battery mate ...a mod should never let a li ion battery go below 2.8v ...it's cut off is probably 3.2v but with the sag your seeing 2.9 being quoted I just use 2.8 all round much easier plus you have a bit of a buffer there :)
     
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  46. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    If you see at the top of the second post mate you can't use the information from both sides it gives a nonsensical answer (just need the wattage or voltage output depending on the device you use)
     
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  47. Vaping_MD_Student

    Vaping_MD_Student New Member

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    I wasn't sure if the information resulting from the first circuit math could/should then be plugged into Ohm's law. Thank you for clarifying. The Reddit post you cited is a really good one and helped to clarify.
     
  48. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    No worries Otto has answered a lot of your question above

    In terms of your 4th question though parralel batteries do tend to be facing the Same direction and series are opposites it very much depends how they wire the battery sled up though take the drone BF for instance it looks like a parralel set up but they have wired the sled up in series ...you'll know if its series as the voltage stated by the manufacturer will be a combined total that or they will say in the overview

    Going higher than CDR won't make your battery go boom unless you have a short, bad battery wrapper, the button is stuck firing, problem with the board or something like that...when you vape unless you chain vape most of the time you are pulsing it but despite what some say though the pulse stats are often overstated on many batteries plus batteries will warm up a fair bit if you don't leave big enough gaps between vapes (when you are above the CDR) that's why for new vapers i and many others say stick to the CDR until you know your way around it all plus to avoid situations like I mentioned above to allow yourself time to get the batteries out and not overly stress them over time
     
  49. KingPin!

    KingPin! Senior Moderator Staff Member Senior Moderator Gold Contributor

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    Let me know if anything else isn't clear mate :)

    Capacity view as a swimming pool it has a defined size in series doesn't matter if you add more batteries it's that size has a single release tap to empty it, so as such discharge rating is taken from the one tap

    Parralel you get to add swimming pools each with there own release tap overall some will be slightly smaller than the last, discharge rating gets applied accross the different taps

    Voltage is the difference in charge between two points or ends of the swimming pool imagine it's got more swimmers up one end to the other in the case of series you have a lot more swimmers in a single pool up one end where as parralel you have an equal to series but they are spread accross their own pools

    Current is the flow rate of the charge between the two points or how quickly they swim to the other end the sag is the batteries resistence to this flow rate image swimming up stream (there is also voltage drop a mods internal resistence through its components but I left this out it's more important on mechs as they lack features found on regulated mods)

    once you get below the low water line (or low voltage cut off) in the pool you refill it

    This is how I think of it all taking away the maths side of it
     
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  50. 32bitlord

    32bitlord TPD Compliant VU Donator Bronze Contributor ECF Refugee

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    Some great info in there, cheers @KingPin!


    Sent from my iPhone using Tapatalk Pro
     
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