Resistance on a Mech Mod

[HTKSmite]

Hello, everyone!

I hope I am posting this in the right place and since I'm on mobile and can't search to see if this question has already been asked, I apologize if I'm repeating this question.

So I just purchased a FUhattan Competition Clone mechanical mod and I had a question about whether or not the coils I currently use would be okay to use with it. My current setup is:

RDA: Blitz Hannya Postless RDA/Blitz
Hugh 3-post RDA

coils: 22AWG/0.4ohm Kanthal A1 Prebuilt

Batteries: Sigelei 18650 35A/2500mAh (which according to what I've read are actually pretty much just rewrapped 20A-25A, 2100mAh cells)

According to the chart I referred to, my battery fully charged at 4.2v and the 0.4ohm coils should put out 10.5amps which is well within safe operating range. But please correct me if I'm wrong! I want to make sure I'm being as safe as possible.

I was told 0.8ohm coils would be better to use with a Mechanical mod. Thoughts on that?

Any help is appreciated!

Thank you for taking the time to read this!

 

[Baditude]

First of all, get yourself some higher quality batteries. As you may or may not be aware, Segelei doesn't actually manufacture batteries. They rewrap castoff cells of unknown quality, and advertise exagerated specifications. Battery Mooch bench tested these batteries a while back, but Segelei could change the cell they rewrap at any point in time, so you never know what the true specs of the battery is. Sigelei 35A 2500mAh 18650 Bench Test Results...shame on you Sigelei!

I recommend you purchase batteries made by Samsung, Sony, or Lg from a reputable battery reseller:

18650 Battery Safety Grades -- Picking a Safe Cell to Vape With
Battery Basics for Mods: The Definative Battery Guide for Vaping

www.liionwholesale.com
www.imrbatteries.com
www.illumn.com
www.rtdvapor.com
www.batterybro.com
www.orbtronic.com
www.nkon.nl
www.akkuteile.de
Welcome to Ecolux. The UK's Battery and accessory specialists. Wide range of authentic leading brands in stock ready for immediate dispatch.​

When you fire your mechanical mod, the coil will draw a specific amount of current (amps) from the battery. That current must not be more than the total amps in continuous discharge rate of the battery, or very bad things could happen.

With a mechanical mod, the two most important things to know when rebuilding coils is to know the amp limit of the battery (also called the continuous discharge rate) you have and to know the measured resistance of your coil. This is where Ohm's Law comes into play. You can determine how many amps a particular coil will draw from a battery in a mechanical mod by using an Ohm's Law calculator. Ohms Law Calculator

Type in your coil's overall measured resistance (ohms) in the "resistance" window, and type in 4.2 volts (the voltage of a fully charged battery) in the "voltage" window. Then click "calculate". The current (amps) that will be drawn from the battery appears in the "current" window.

When you fire your mechanical mod, it will draw a specific amount of current (amps) from the battery. That current must not be more than the total amps in continuous discharge rate of the battery, or very bad things could happen.

The below calculations from the Ohm's Law calculator demonstrate that the lower you go in ohms the higher the amp requirement becomes. You are also putting a lot of faith into a cheap ohm reader in being precisely accurate to the tenth/hundreth of an ohm. Always tend to err on the side of safety when you make your builds by allowing some safety head room.

1.0 ohm = 4.2 amp draw
0.9 ohm = 4.6 amp draw
0.8 ohm = 5.2 amp draw
0.7 ohms = 6 amp draw
0.6 ohms = 7 amp draw
0.5 ohms = 8.4 amp draw
0.4 ohms = 10.5 amp draw
0.3 ohms = 14.0 amp draw
0.2 ohms = 21.0 amp draw
0.1 ohms = 42.0 amp draw
0.0 ohms = dead short = battery goes into thermal runaway​

Everyone is free to set their own parameters, and I can only say what mine are.

I try to never exceed 50% of the CDR (continuous discharge rating) of a fully charged battery (4.2v). So with a 20A batteries, that would be 10A. The above Ohm's Law Calculator tells me that a .4 ohm build is as low as I would want to use.

The reason that I place a 50% limit is because as a battery ages the mAh of the battery degrades, as the mAh degrades so does the batteries c rating (amp limit). So down the road, your 20A battery may only be a 10A battery.

Explain it to the Dumb Noob: Ohm's Law Calculations

I would use either 26 or 28 gauge wire instead of 22 gauge. Either will heat up faster; 22 gauge is thicker wire with more mass and must take forever to heat up.

 

[MMW]

Welcome to the forum. Your build in resistance will correspond to what kind of vape you prefer.

Your .4 build with 22g will get you right around 44w and will draw 10.5A from a fully charged cell. It's all preference really, but if you like a mellower vape .8 would be that.
Any reason why for 22g? Ifyou use a 26g you will notice it will leat and cool down a lot quicker.

Personally, I would get a different battery. One that is a trusted, tried, and true.
Always inspect your batteries periodically for tears and rewrap when needed.

 

[HTKSmite]

Welcome to the forum. Your build in resistance will correspond to what kind of vape you prefer.

Your .4 build with 22g will get you right around 44w and will draw 10.5A from a fully charged cell. It's all preference really, but if you like a mellower vape .8 would be that.
Any reason why for 22g? Ifyou use a 26g you will notice it will leat and cool down a lot quicker.

Personally, I would get a different battery. One that is a trusted, tried, and true.
Always inspect your batteries periodically for tears and rewrap when needed.

No particular reason for the 22g. It was just a pack of prebuilt coils I came across when I wanted to buy them in bulk since I don't know how to make my own. And a pack of 100 coils for around $20 didn't seem too bad.

Thank you for your reply! I'll look into getting 26g and some new batteries from a reputable manufacturer.

 

[HTKSmite]

First of all, get yourself some higher quality batteries. As you are apparantly aware, Segelei doesn't actually manufacture batteries. They rewrap castoff cells of unknown quality, and advertise exagerated specifications. Battery Mooch bench tested these batteries a while back, but Segelei could change the cell they rewrap at any point in time, so you never know what the true specs of the battery is. Sigelei 35A 2500mAh 18650 Bench Test Results...shame on you Sigelei!

I recommend you purchase batteries made by Samsung, Sony, or Lg from a reputable battery reseller:

18650 Battery Safety Grades -- Picking a Safe Cell to Vape With
Battery Basics for Mods: The Definative Battery Guide for Vaping

www.liionwholesale.com
www.imrbatteries.com
www.illumn.com
www.rtdvapor.com
www.batterybro.com
www.orbtronic.com
www.nkon.nl
www.akkuteile.de
Welcome to Ecolux. The UK's Battery and accessory specialists. Wide range of authentic leading brands in stock ready for immediate dispatch.​

When you fire your mechanical mod, it will draw a specific amount of current (amps) from the battery. That current must not be more than the total amps in continuous discharge rate of the battery, or very bad things could happen.

With a mechanical mod, the two most important things to know when rebuilding coils is to know the amp limit of the battery (also called the continuous discharge rate) you have and to know the measured resistance of your coil. This is where Ohm's Law comes into play. You can determine how many amps a particular coil will draw from a battery in a mechanical mod by using an Ohm's Law calculator. Ohms Law Calculator

Type in your coil's overall measured resistance (ohms) in the "resistance" window, and type in 4.2 volts (the voltage of a fully charged battery) in the "voltage" window. Then click "calculate". The current (amps) that will be drawn from the battery appears in the "current" window.

When you fire your mechanical mod, it will draw a specific amount of current (amps) from the battery. That current must not be more than the total amps in continuous discharge rate of the battery, or very bad things could happen.

The below calculations from the Ohm's Law calculator demonstrate that the lower you go in ohms the higher the amp requirement becomes. You are also putting a lot of faith into a cheap ohm reader in being precisely accurate to the tenth/hundreth of an ohm. Always tend to err on the side of safety when you make your builds by allowing some safety head room.

1.0 ohm = 4.2 amp draw
0.9 ohm = 4.6 amp draw
0.8 ohm = 5.2 amp draw
0.7 ohms = 6 amp draw
0.6 ohms = 7 amp draw
0.5 ohms = 8.4 amp draw
0.4 ohms = 10.5 amp draw
0.3 ohms = 14.0 amp draw
0.2 ohms = 21.0 amp draw
0.1 ohms = 42.0 amp draw
0.0 ohms = dead short = battery goes into thermal runaway​

Everyone is free to set their own parameters, and I can only say what mine are.

I try to never exceed 50% of the CDR (continuous discharge rating) of a fully charged battery (4.2v). So with a 20A batteries, that would be 10A. The above Ohm's Law Calculator tells me that a .4 ohm build is as low as I would want to use.

The reason that I place a 50% limit is because as a battery ages the mAh of the battery degrades, as the mAh degrades so does the batteries c rating (amp limit). So down the road, your 20A battery may only be a 10A battery.

Explain it to the Dumb Noob: Ohm's Law Calculations

I would use either 26 or 28 gauge wire instead of 22 gauge. Either will heat up faster; 22 gauge is thicker wire with more mass and must take forever to heat up.

A lot of useful information here. Thank you very much! I'll sit down and do some more research after work. Probably at least get some better batteries ordered this evening from a reputable manufacturer/seller.

I really appreciate you taking the time to post such an informative reply to a question that surely isn't new to the forum.

 

[Baditude]

A lot of useful information here. Thank you very much!

Two more for you:

A Beginner's Guide to Your First Mechanical Mod

• Covers the differences between a mechanical vs. regulated mod, essential safety accessories, optional safety accessories to add layers of safety to your mech, routine maintanance, use of proper batteries, proper ventilation, low resistance vaping, and faux hybrid mods.

Information Resources for Your First RBA

• An essential read and referrance guide for someone new to rebuilding coils. Includes a multitude of useful links on battery safety, mod safety, coil meters, coil building, and the differences in the three types of RBA's.

 

[HTKSmite]

Two more for you:

A Beginner's Guide to Your First Mechanical Mod

• Covers the differences between a mechanical vs. regulated mod, essential safety accessories, optional safety accessories to add layers of safety to your mech, routine maintanance, use of proper batteries, proper ventilation, low resistance vaping, and faux hybrid mods.

Information Resources for Your First RBA

• An essential read and referrance guide for someone new to rebuilding coils. Includes a multitude of useful links on battery safety, mod safety, coil meters, coil building, and the differences in the three types of RBA's.

Wow, thank you again! I just ordered a set of Sony VTC5 18650s and some 28g 0.8ohm coils. I think I'll be good to go now. Still going to do a bit more research, but from what I see so far those were the major things I needed to get that I didn't already have.

 

[Eskie]

Do you have a device to check the resistance of those "premade" coils? There can be significant differences in resistance between what's on the box and what the actual resistance is (referring to precoiled wire, not a factory coil, although variance can be seen there as well). This can be an issue if you're using it on a mech mod. Just because it's labelled 0.4 ohm (or whatever) double check it yourself before relying on that number for your calculations.

 

[HTKSmite]

Do you have a device to check the resistance of those "premade" coils? There can be significant differences in resistance between what's on the box and what the actual resistance is (referring to precoiled wire, not a factory coil, although variance can be seen there as well). This can be an issue if you're using it on a mech mod. Just because it's labelled 0.4 ohm (or whatever) double check it yourself before relying on that number for your calculations.

Yes, I've got an ohm reader that I've been using. For the most part the prebuilt coils I've been buying have been between 0.39ohms and 0.42ohms. So there's variance, but not a whole lot. And I'll also be checking every new build with the 0.8ohm coils I ordered to make sure before putting them on the Mech.

I can also toss the builds onto one of my regulated mods and check their readout, yes? For a second measurement from another device?

 

[Eskie]

It's just worth the check as you don't have the "safety net" of a regulated mod. That variance you saw is not significant. I do remember once buying some "super cross stapled quarter wrap superconducting coil" that was supposed to be 0.3 ohm that was actually 0.16 ohm. On my mod it's not the end of the world. If I unknowingly stuck that on a mech I might have ended up having a really bad day. Not knocking buying well made prewrapped coils/wires, there are some beauties out there that I could never make myself, but yes, check each new build for yourself.

 

[VHRB2014]

Iv never trusted those Sig batteries. If you look hard they can be found for like 2 bucks each, at that price point I guess they are having hard time selling them, so I figure its worth about what they are asking for them. Batteries are the one thing I will not cheap out on, the rest I can analyze and modify, but batteries you have to trust implicitly. So I only buy batteries I trust from trusted sellers.

 

[HTKSmite]

Iv never trusted those Sig batteries. If you look hard they can be found for like 2 bucks each, at that price point I guess they are having hard time selling them, so I figure its worth about what they are asking for them. Batteries are the one thing I will not cheap out on, the rest I can analyze and modify, but batteries you have to trust implicitly. So I only buy batteries I trust from trusted sellers.

Yeah, it seems that the battery is the main point of interest in a Mech mod. Thanks to Baditude's list that he posted, I picked up a set of Sony VTC5s from RTD Vapor. I don't understand why somebody would cheap out on such an integral part of the unit when they're really not that expensive. The only reason I got the Sigelei batteries is because they came with the little 90w Spark that I bought for work and I haven't needed anything better until now.

 

[VHRB2014]

LOL, Ya, I got a couple Kamry batteries here that are never used (came with the old Vamo!). Might as well use them for target practice now, :?)

 

[Bunnykiller]

I'd like to add a bit of info to this thread.... a short is a condition in which the amperage draw exceeds the power limitations or the supply or the circuitry....