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Question about low resistance, amp limit and batteries

Trusty_vapor

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I was wondering. They obviously say not to exceed your batteries amp limit. So for instance if it's a series mod, and you had 2 18650's, does that mean you have twice the amp limit of the batteries if the batteries are in series? Say you have a 20a battery, would this mean you now have 40a as a possible safe discharge of the batteries? And for a parallel mode would it just mean that you're drawing half the amperage that you normally would on a single battery mod? So if something requires 20 amps on a single 18650 mod if you had the same characteristics on a dual you would draw 10 from each battery
 

Droogbc

Silver Contributor
Member For 4 Years
Amp limit does not change in series. If you are using 20 amp cdr cells it's 20 amps max in series as well.

Parallel would increase your amp headroom, but it wouldn't quite double it.
 

HondaDavidson

Gold Contributor
Member For 4 Years
Batts stacked plus to plus and neg to neg are parallel plus to negative is series.

Series volts double but load is as per 1 battery. In parallel loads double while volts stay at single batt levels.

Sent from my SCH-I605 using Tapatalk
 

Trusty_vapor

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So if you use 2 20 amp batteries and you are at 25 amps on the mod you basically are playing with luck?
 

Trusty_vapor

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Why are manufacturers making double 18650s that can go to "200w"?
 

Droogbc

Silver Contributor
Member For 4 Years
Those mods generally pulse the current after a certain wattage, sending bursts of up to 200 watts to the atty. Still best to use a 25-30 cdr cell like the vtc4 if you're going to be pushing higher wattages on a dual cell regulated mod.
 

HondaDavidson

Gold Contributor
Member For 4 Years
Depends on the mods amp limit and how the regulation is being done. Regardless a regulated mod won't fire outside what is safe fir it. You try to draw too much power it turns off.

Sent from my SCH-I605 using Tapatalk
 

Trusty_vapor

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So realistically if a regulated mod is firing. Youre good to go?
 

Droogbc

Silver Contributor
Member For 4 Years
Assuming you're using married sets of name brand (LG, Samsung or Sony) cells that have a cdr of 20 amps or more, yeah, if the regulated mod fires you're pretty much good to go.

Do be mindful of your battery wrappers, of course. If they get torn up, rewrap them or replace them.

Also, if you happen to drop your mod and dent the batteries, replace them.

Otherwise, vape on.
 

BoomStick

Gold Contributor
Member For 5 Years
I have a feeling you're trying to apply mech mod equations to a variable wattage mod. They don't work the same. Coil current isn't the same as battery current when using vw devices which means coil resistance has nothing to do with battery current in a vw mod. Watt setting divided by total battery voltage gets you battery current. So 80 watts pulls roughly 10 amps from two 18650's in series in a vw mod regardless of what build you use.
 

HondaDavidson

Gold Contributor
Member For 4 Years
I have a feeling you're trying to apply mech mod equations to a variable wattage mod. They don't work the same. Coil current isn't the same as battery current when using vw devices which means coil resistance has nothing to do with battery current in a vw mod. Watt setting divided by total battery voltage gets you battery current. So 80 watts pulls roughly 10 amps from two 18650's in series in a vw mod regardless of what build you use.
This is true.... this is also why I fear regulated mod more than mechs. I trust me to keep me safe more than I trust technology and circuitry. I won't vape beyond the battery rating.. if that means I can't vape at max wattage so be it until I get a better battery.

Sent from my SCH-I605 using Tapatalk
 

BoomStick

Gold Contributor
Member For 5 Years
My opinion is if you're pushing the max wattage of your mod, you should get one with a higher power limit. Running one wide open usually means unnecessary stress on the battery and the device as well as crap runtime. My concern isn't so much about safety as it is the lifespan of the device and batteries and not swapping batts every hour or two. Most newer mods use one 18650 for every 70 or so watts of power they offer. Which means they're designing them for use with 20 amp cells. So use quality 20 amp batteries and run it how you want, just know that at the top of the power range you're running out of power and battery. I prefer not to run my stuff near redline. Still safe, but....
 

Trusty_vapor

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Just throwing this out there for everyone. Not all mods where the batteries go in the same way are a parallel battery mod. For exampl . The koopor primus 300w. The batteries all go in the same way so one would think it's a parallel mod, but the board itself actually sets them up in series the way it's built. Just watched a video from djlsb vape s showing this. If interested go to about the 18 minute mark and he will explain.
 

r055co

VU Donator
Platinum Contributor
Member For 4 Years
Just throwing this out there for everyone. Not all mods where the batteries go in the same way are a parallel battery mod. For exampl . The koopor primus 300w. The batteries all go in the same way so one would think it's a parallel mod, but the board itself actually sets them up in series the way it's built. Just watched a video from djlsb vape s showing this. If interested go to about the 18 minute mark and he will explain.
Yep and the Reuleaux and Hohmwrecker G2 are in series
 

Jim_MDP

Gold Contributor
Member For 4 Years
Simple enough to tell series vs. parallel battery sled... if the mod lights up with only one battery installed... it's parallel.

For regulated mod battery amp draw safety... we only really calculate what would be the max or worst case and that's at max watts with a depleted cell.

For me... that says keep it below 60 watts per 20A CDR battery in regular all day usage.
If I'm near or over that for a particular build and want to keep it going, everything Boomstick says above applies... shift to a mod with more cells.
(all of mine are 20A CDR... 25R, HG2, HE4.
If you own higher CDR cells... do your own math. :p )

I don't race around in my cars, I don't redline my mods.
And I don't need to recalculate the amp draw all the time.
 

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