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Some questions before my first build

I've been reading articles, looking at pictures of other people's builds, and playing with theoretical builds on the calculators on steam-engine, and I think I have everything figured out.

My current setup is a panzer clone mechanical mod, a big dripper clone set at 1.1ohms, and an efest 2500mah battery. I've read that the battery is actually a rewrapped LG HE2 with a continuous discharge of 20amps. If my math is correct that means I can go as low as .21ohms. Can someone confirm or correct my math, and possibly give any suggestions you can think of. Thanks in advance

TL:DR have researched, have a 20amp battery, think I can go as low as 0.21ohms, need confirmation or correction, suggestions welcome.
 

nightshard

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Your calculations are correct, but i wouldn't go that low, keep at 0.3 to be on the safe side.
 

State O' Flux

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If my math is correct that means I can go as low as .21ohms. Can someone confirm or correct my math, and possibly give any suggestions you can think of. Thanks in advance
As you are relatively new to rebuilding... just because you can do something doesn't mean you should.
rolleyes.gif


If you include a "margin of safety", expressed as a percentage of available maximum continuous "discharge rate"... even as little as 10% of the stated value... you'll see that your minimum desired resistance is 0.23Ω.

Unless you own a milliohm meter and know how to use it... the typical ohm meter/build box and/or DMM's accuracy tends to come into question as we move closer to full continuity (aka - a dead short)... nightshard's suggestion of 0.3Ω or higher is, as a starting point, a safe and reasonable one.

Too many beginners (as well as more advanced vapists) fail to understand that there's a good bit more to it than one simple Ohm's Law calculation.
Yes... if you are quite familiar with your batteries capabilities, you can take the momentary or pulse discharge rate (advertized - if any... or conservative calculation based on knowledge and experience) and absolute minimum resistance into account... but only if you are certain of the mech / RDA combination's total conductive loss / voltage drop.
 
Thank you for the advice and quick replies. I will definitely keep the safety margin in mind. I come from working on cars where the safety margin is needed, but not like it is here, so I completely get it. I don't have own a milliohm meter, but I'm getting ready to go buy one from my local B&M. Thanks to everyone here, I have learned a lot reading through here and look forward to continue to do so.
 

UncleRJ

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Get that ohm tester and adhere to the advice you have been given and you will be fine.
 

vaporelse

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I know quite a few veteran vapers who feel that 0.5 ohms is the sweet spot, and that could be why Aspire built the Atlantis with a 0.5 coil. It really is a great place to start. It is easy to experiment, but knowing what 0.5 will give you is a solid reference mark to have.
 
I picked up the milliohm meter, and got right to it. I kept it pretty simple for my first build: 26g kanthal dual micro coil, 9 wraps, comes in at .56ohms. I need to work on getting my coils tighter, but I am pretty happy with the way it came out.
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Jackson

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I've been reading articles, looking at pictures of other people's builds, and playing with theoretical builds on the calculators on steam-engine, and I think I have everything figured out.

My current setup is a panzer clone mechanical mod, a big dripper clone set at 1.1ohms, and an efest 2500mah battery. I've read that the battery is actually a rewrapped LG HE2 with a continuous discharge of 20amps. If my math is correct that means I can go as low as .21ohms. Can someone confirm or correct my math, and possibly give any suggestions you can think of. Thanks in advance

TL:DR have researched, have a 20amp battery, think I can go as low as 0.21ohms, need confirmation or correction, suggestions welcome.

You don't have to overthink that. I been hearing the same spiel since 2009. Always the 'sky is falling' posts from the prophets of doom about exceeding max discharge ratings. Folks here are talking about a cushion, the major manufacturers rating itself already has a cushion built in. Today's batteries are especially tough.

Just buy batteries from the top tier, Samsung, LG and Panasonic/Sanyo, they all have very good safety records. I wouldn't buy any of new breed of unknown brand cells that are popping up though. There is also the battery UL1642 cert (and some UN ones also) there are a number of tests that need to be done. Here's a few, from a Samsung datasheet.


9.1 Overcharge Test
Test method: To charge the standard charged cell with 12V and 2150mA at 25℃ for 2.5 hours.
Criteria: No fire, and no explosion.

9.2 External Short-circuit Test
Test method: To short-circuit the standard charged cell by connecting positive and negative terminal by less than 100mΩ wire for 3 hours.
Criteria: No fire, and no explosion.

9.3 Reverse Charge Test
Test method: To charge reversely the standard charged cell with charge current 2150mA for 2.5 hours.
Criteria: No fire, and no explosion.

have a 20amp battery, think I can go as low as 0.21ohms,
And what is the right way to check for amp draw? Seems you used 4.2V, you'll never vape at 4.2V off a battery. I would think that the voltage should be determined/measured while under load, which will give you the real amps that the battery is providing.

Food for thought. :)
 

BoomStick

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I've heard more than one story of mechanical failure or operator error resulting in the circuit getting closed and staying closed. If this were to happen, having a build that doesn't cause the battery to overheat would be better than one that is only safe during short periods of intentional firing. Just another consideration.
 

ConcreteBob

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I completely killed an Efest battery recently. Partly to prove a point to a friend, partly to see what the battery would do. I fired it in an old stainless steel Cartel clone, with 18ga 3 wrap dual coils on my Dark Horse Tobeco clone. I think it came out to around .03 ohms or something equally ridiculous. 5 seconds per fire. Made it through 4 rounds and self destructed, with pretty minimal venting actually. No, I did not do this in my hand, before anyone asks. Had it in a metal tub and used a rack with vise grips and a lever to actuate it.
 

JediTT

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I know batteries aren't as scary as some people make them sound but seeing as we're replying to a thread in the NEW BUILDERS CORNER part of the forums it might not be good to downplay the safety aspect. Until you're comfortable and have some knowledge it's always good to be a bit "extra" cautious.
 

JediTT

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I picked up the milliohm meter, and got right to it. I kept it pretty simple for my first build: 26g kanthal dual micro coil, 9 wraps, comes in at .56ohms. I need to work on getting my coils tighter, but I am pretty happy with the way it came out.

Looks good for first build and .5 is a decent vape. Take it slow and try all different builds to find out what you like and what works for you. Also if you get those coils red hot and then stop firing, you can take some tweezers and squeeze them together while they're still hot. Check it again in ohm meter if you do this because it changes the resistance a bit.
 

ConcreteBob

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I know batteries aren't as scary as some people make them sound but seeing as we're replying to a thread in the NEW BUILDERS CORNER part of the forums it might not be good to downplay the safety aspect. Until you're comfortable and have some knowledge it's always good to be a bit "extra" cautious.
Absolutely. I did my rather stupid little experiment in a controlled fashion, I'm an experienced builder, and I knew what was likely to happen. Regardless of how little it vented, it got tremendously hot. You really don't want that to happen in your hand, pocket or in front of your face. Always, and I mean ALWAYS, know the limits of your equipment, and always build within a safe margin.
 

MKPM

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"Look momma! First build and he's already making offset legs!!" Well done sir....gently pinch those coils on the cool-down and they will be snug and even burning. I've seen some proper hash-ups on first attempts, but you have been doing your homework! Starting at .5ohms is a good start....most of us on the forum started at 1.8ohms and worked down.
 

MKPM

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Absolutely. I did my rather stupid little experiment in a controlled fashion, I'm an experienced builder, and I knew what was likely to happen. Regardless of how little it vented, it got tremendously hot. You really don't want that to happen in your hand, pocket or in front of your face. Always, and I mean ALWAYS, know the limits of your equipment, and always build within a safe margin.
I am a member of: "Brotherhood of the Glowing Tube", "Association of Singed Lips", "Branded Fingers Anonymous". Welcome to the club!
 

JediTT

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"Look momma! First build and he's already making offset legs!!" Well done sir....gently pinch those coils on the cool-down and they will be snug and even burning. I've seen some proper hash-ups on first attempts, but you have been doing your homework! Starting at .5ohms is a good start....most of us on the forum started at 1.8ohms and worked down.
He even centered the coils!!!
 

ConcreteBob

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I am a member of: "Brotherhood of the Glowing Tube", "Association of Singed Lips", "Branded Fingers Anonymous". Welcome to the club!
Happy to be aboard, sir!
Only killed one battery by accident so far. I hope that's enough to insure my continued membership...
 

ConcreteBob

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I picked up the milliohm meter, and got right to it. I kept it pretty simple for my first build: 26g kanthal dual micro coil, 9 wraps, comes in at .56ohms. I need to work on getting my coils tighter, but I am pretty happy with the way it came out.
DSC_0031_zpszppy1rhe.jpg


DSC_0026_zpsguo6kgwo.jpg


DSC_0030_zpsnuhquqio.jpg


DSC_0032_zpsmlfcenuo.jpg
That's a nice looking build. How's the vape profile?
 

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