Can anyone answer this ohm question

[m3nace]

Ok so I lurk the forum alot learning about building and I think I have a basic understanding of ohms law and the ohms calculator.. here it goes
I put in my battery c rating which is 10 and my mah which is 2000 and the ohms are 3.7 does that mean 3.7 ohms is the most stress I can put the battery under I say stress cuz I know if I build it at 3.7 itll kill the battery etc so I olan on building maybe .6 to .8 to protect my face and battery

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[suspectK]

3.7 ohms is dangerous and subohming isn't? You have it backwards. The higher the resistance, the less current being drained from your battery=less stress on your battery and concern with continuous amp rating. Less resistance=more current=more stress on your battery and more concern of your continuous current rating of your battery.

 

[suspectK]

Can you put all your values in more of a variable/formula type explanation?

 

[DarkestKnightz]

Thats a bit confusing the way you put it down. I can link you a good video to explain the whole "Ohms Law" thing for you
A PBusardo Review - The Kick by Evolvapor - ElectronicStix - YouTube
PBusardo laying it out

 

[m3nace]

I meant thw ohms comes out to be .37 not 3.7

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[m3nace]

Sorry bad typo lmao

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[suspectK]

Yeah, that is a pretty big typo, but it's hard to figure out your information...the mAh rating is just an easy measurement for people to identify capacitance in batteries..does't have anything to do about your actual current rating, but your continuous current rating will be reflective of it. A higher capacity battery will have a lower current rating.

Battery type and continuous and pulse current rating you know of?
Regulated? unregulated? what PV?

 

[m3nace]

I read somewhere to figure out what your battery is capable of you use this formula

C rating x mah / 1000
Then using ohms law
With a 3.7 volt battery and a c rating of 10 the ohms come out to be .37
And I figured this is the lowest that the battery can be stressed right? Using a .37 ohm build on my patriot atty origin mod
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[suspectK]

Using that formula:
10 Amps X 2000 mAh=10 Amps X 2Ah=20 Amps continuous.

20 Amps with 3.7 Volts= 3.7 Volts / 20 Amps= 0.185 Ohms... It's always suggested by most safety practicing members on ECF not to dip below 5 deciohms/ 0.5 Ohms with coils.. I honestly don't get subohms, unless you're using a mechanical. I feel like I get better function with a micro/nano coil.

 

[Thrasher]

hold on kids.

when a 3.7 battery is fully charged it will actually be at 4.2 volts to start
.37 ohms will actually be at 11.4 amps and 46 watts!!!!

Ohm's Law Calculator

most of the standard high drain batteries run at 10 amps with a couple of specials batteries that run at 20-30 amps.

if you havent already start with a .8 ohm coil. plenty of vapor no need to go so low.... please be very careful and sure of what your doing when you step under .5 ohms this is a lot of power.

I do not remember the c rating formula off the top of my head.

 

[suspectK]

Oops...Thanks thrasher.

 

[Baditude]

Ok so I lurk the forum alot learning about building and I think I have a basic understanding of ohms law and the ohms calculator.. here it goes
I put in my battery c rating which is 10 and my mah which is 2000 and the ohms are 3.7 does that mean 3.7 ohms is the most stress I can put the battery under I say stress cuz I know if I build it at 3.7 itll kill the battery etc so I olan on building maybe .6 to .8 to protect my face and battery.

Your understanding and terminology is way off. Higher ohms are safer than sub-ohms by far. Using a coil that is < 0.8 ohms requires special IMR batteries which have a continuous discharge rating (CDR) of 15-20 amps (see below chart of recommended batteries). Most IMR batteries have a CDR of only 10 amps.

You need to know the continuous discharge rate in amps of your battery to know how low in ohms you can go. NEVER exceed this limit. It's a very wise idea to allow some "wiggle room" just to stay on the safe side because coil resistance can change for no apparent reason.

To find the CDR, you must know the C rating of the battery, which may be listed in the product description or you may need to research for it. Here's the way to find your battery's continuous discharge rate: multiply the number from the C rating by the mAh capacity. Keep in mind that 1000 milliamps equals one amp. Here's an example, using an 2000mAh 10C battery:

2000mAh - 10C
2000 milliamps = 2 amps
2 Amps x 10 = 20 amps continuous discharge

This means that you can safely draw up to 20 amps continuously from that 2000mAh 10C battery without doing damage to it. WHAT DOES A BATTERY'S C RATING MEAN?


You also need to keep the below Ohm's Law Calculator bookmarked somewhere. It's easy to use: Type in the voltage (4.2 volts) and the resistance of the coil (X.X ohm) and then click calculate. The "current" will be the amps that the coil will pull from the battery.

I recommend wrapping your coils at 0.9 ohm or higher with 10 amp CDR battery. If you feel the need to go lower in ohms, purchase one of the batteries below that have a 20 amp or higher continuous discharge rate.

Ohm's Law Calculator

AW IMR
18650 2000mah 10Amp CDR
18650 1600mah 24A

MNKE IMR
18650 1500mah ​20A

Panasonic ​or Orbtronic hybrid
CGR18650CH (IMR/hybrid) 2250mAh 10A
NCR18650PD (LiNiCoAl) 2900mAh 10A
Orbtronic 18650 SX22 (hybrid) 2000mAh 22A

Samsung hybrid (LiNiCoMnP)
INR18650-22P 2200mAh 10A
INR18650-20R 2000mah 22A

Sony
us18650v3 IMR 2250mAh 10A
us18650vct3 (hybrid) 1600mAh 30A

Efest IMR
18650 (IMR/hybrid) 2250mAh 10A
18650 2000mAh 10A
18650 1600mAh 30A

* AW IMR 18490 (1100mah) 8.8A

*AW IMR 18350 ​(700mah) 6A​

BATTERY BASICS FOR MODS: IMR or PROTECTED?

Make sure that you own and know how to use a digital multimeter. If you don't, you have NO BUSINESS rebuilding your own coils. Coil resistance can change for no apparent reason, so its vital to check it frequently.
HOW TO USE A MULTIMETER

All batteries are dangerous if not used properly or misused. Below is an AW IMR battery that hard-shorted and went into thermal runaway. What you see is what remains of the metal casing, and the contents of the battery blown out like an accordian when the battery vented. You can only imagine what this would do inside of a metal tube like a mechanical mod.

 

[m3nace]

Your understanding and terminology is way off. Higher ohms are safer than sub-ohms by far. Using a coil that is < 0.8 ohms requires special batteries which have a continuous discharge rating (CDR) of 15-20 amps (see below chart of recommended batteries). Most IMR batteries have a CDR of only 10 amps.

You need to know the continuous discharge rate in amps of your battery to know how low in ohms you can go. NEVER exceed this limit. It's a very wise idea to allow some "wiggle room" just to stay on the safe side because coil resistance can change for no apparent reason.

To find the CDR, you must know the C rating of the battery, which may be listed in the product description or you may need to research for it. Here's the way to find your battery's continuous discharge rate: multiply the number from the C rating by the mAh capacity. Keep in mind that 1000 milliamps equals one amp. Here's an example, using an 2000mAh 10C battery:

2000mAh - 10C
2000 milliamps = 2 amps
2 Amps x 10 = 20 amps continuous discharge

This means that you can safely draw up to 20 amps continuously from that 2000mAh 10C battery without doing damage to it. WHAT DOES A BATTERY'S C RATING MEAN?


You also need to keep the below Ohm's Law Calculator bookmarked somewhere. It's easy to use: Type in the voltage (4.2 volts) and the resistance of the coil (X.X ohm) and then click calculate. The "current" will be the amps that the coil will pull from the battery.

I recommend wrapping your coils at 0.9 ohm or higher with 10 amp CDR battery. If you feel the need to go lower in ohms, purchase one of the batteries below that have a 20 amp or higher continuous discharge rate.

Ohm's Law Calculator

AW IMR
18650 2000mah 10Amp CDR
18650 1600mah 24A

MNKE IMR
18650 1500mah ​20A

Panasonic ​or Orbtronic hybrid
CGR18650CH (IMR/hybrid) 2250mAh 10A
NCR18650PD (LiNiCoAl) 2900mAh 10A
Orbtronic 18650 SX22 (hybrid) 2000mAh 22A

Samsung hybrid (LiNiCoMnP)
INR18650-22P 2200mAh 10A
INR18650-20R 2000mah 22A

Sony
us18650v3 IMR 2250mAh 10A
us18650vct3 (hybrid) 1600mAh 30A

Efest IMR
18650 (IMR/hybrid) 2250mAh 10A
18650 2000mAh 10A
18650 1600mAh 30A

* AW IMR 18490 (1100mah) 8.8A

*AW IMR 18350 ​(700mah) 6A​

BATTERY BASICS FOR MODS: IMR or PROTECTED?

Make sure that you own and know how to use a digital multimeter. If you don't, you have NO BUSINESS doing Sub-Ohm vaping. Coil resistance can change for no apparent reason, so its vital to check it frequently.
HOW TO USE A MULTIMETER

All batteries are dangerous if not used properly or misused. Below is an AW IMR battery that hard-shorted and went into thermal runaway. What you see is what remains of the metal casing, and the contents of the battery blown out like an accordian when the battery vented. You can only imagine what this would do inside of a metal tube like a mechanical mod.

View attachment 262992

Im not trying sub ohms yet until im clear on everything I just wanna make sure im reading the outputs of the calculator correctly and I know sub ohms is more dangerous I made a bad typo lol

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[m3nace]

Thanks thrasher and suspectk I think I got a better understanding since I cleared my typo .... one more question lets say I build a wrap and I test it on my ohm meter without cutting the excess will the ohm meter read differently if I cut the excess wire?

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[suspectK]

You don't have to cut the excess wire. If the wire continued to make a circuit, it would create a series circuit, but that isn't the case, since the loop isn't made.

Just don't forget you didn't cut/break the wire and forget about it before vaping. Then, you're going to wonder why things are bouncing around so much.. Because the positive contact with wire to the body of the atomizer is a circuit.

 

[m3nace]

Gotcha thanks alot my knowledge and understanding grows every time I lurk but now its even easier since I can ask questions lol

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