Of Ohms. wth?

[Spencer87]

So I bought a rba with my Nemesis clone off a buddy a few weeks ago. Anyways, then, I bought my MVP, Nemesis lay lost and forgotten mostly. and now its a little messed, I cant figure a way out to screw it on properly so the button presses nicely, but at least it works, Anyways, I didnt touch it much. The rba that buddy made me tasted pretty bad. Anyways, Today, I wanted to vape some peppermint. so, I figured I would build a coil. Not so bad, took me about 10 min, and I popped the single coil in to my rba, and dripped and popped that in to my MVP, Which read 2.0 ohms initially. Now it read 1.1

Strange, Okay, Took a hit. Took another. Nothing the second time. Ohms read it,... and now its down to 0.7.... that seems silly to me. 0.7

sigh.
What did i do wrong.....? I know the MVP wont vape past 0.8... but how do i make a coil that has more ohms?

 

[Elizabeth Baldwin]

How many wraps did you use? What gauge of kanthal? And what size tool did you wrap the kanthal on?

 

[Baditude]

Sounds like you had a short in the coil. What kind of coil did you make? Simple spiral or a microcoil (compressed loops so all loops are touching)? Spiral coils are more likely to get hot spots (shorts) than microcoils. Did the coil glow evenly when you tested it, inside out? Make sure the post screws didn't become loose.

microcoil

Adding more loops will give you more resistance (higher ohm).

Coil wrapping | Steam Engine | free vaping calculators

 

[Spencer87]

I did 5 wraps. All touching. Not sure the gage... The guy gave me some... And it did glow evenly, I think. I just built a second coil... Which brought it DOWN to 0.4...
But, Although I need to drip more, It TASTES AMAZING!!!!!

I am thinking next time, Ill build 4 coils... see how that tastes.

 

[Ryedan]

I did 5 wraps. All touching. Not sure the gage... The guy gave me some... And it did glow evenly, I think. I just built a second coil... Which brought it DOWN to 0.4...
But, Although I need to drip more, It TASTES AMAZING!!!!!

I am thinking next time, Ill build 4 coils... see how that tastes.

What battery are you using in the Nemesis?

The lower you go in resistance the more amps you will draw from the battery. Draw too many amps and you'll cause the battery to heat up and eventually vent. Here's a Sub Ohm Battery Chart that list most of the safer chemistry batteries out there.

 

[Baditude]

What battery are you using in the Nemesis?

The lower you go in resistance the more amps you will draw from the battery. Draw too many amps and you'll cause the battery to heat up and eventually vent. Here's a Sub Ohm Battery Chart that list most of the safer chemistry batteries out there.

I was wondering the same thing.

When doing sub-ohm coils especially, you have to know the amp limit of the battery. List of Battery Amp Limits

Use the Ohm's Law Calculator to determine if the coil resistance of your RBA will pull more amps than the battery has to provide. Going over the amp limit of the battery can have catastrophic results.

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

 

[Spencer87]

What battery are you using in the Nemesis?

The lower you go in resistance the more amps you will draw from the battery. Draw too many amps and you'll cause the battery to heat up and eventually vent. Here's a Sub Ohm Battery Chart that list most of the safer chemistry batteries out there.

Oh wow.. Yea, I dont understand most of that, But My Battery is not even on there
I use Efest 2500 3.7 V.

If I dont chain vape it should be okay, it wont heat up as much i would think? What is venting anyways...?

 

[Spencer87]

plus the battery says 35a
I assume that means can go up to 35 Amps?

 

[ImThatGuy]

At full charge you're at 4.2 volts. You have the purple efest batteries that are capable of drawing 35 amps pulse and 20 amp continuous.

 

[Spencer87]

Okay, So, Just to Clarify, Then,
Means I can safely Vape the 0.4 ohm?

 

[ImThatGuy]

Yup.

10 characters.

 

[Baditude]

What is venting anyways...?

Venting occurs when you push a battery harder than it would like. When a coil pulls more amps than the battery actually has to give. Thermal runaway. If you're lucky, a battery will only vent gas hot enough to cause second degree burns; if you're not lucky it could turn your mod into a pipe bomb.

 

[TheRac25]

i wonder what kind of forces are involved in a catastrophic lion failure, the tiny vent holes i see in mechs do not appear to be adequate, has anyone done a test like this or are they just guessing those tiny holes will be ok?

 

[Baditude]

i wonder what kind of forces are involved in a catastrophic lion failure...

 

[BrantlyT]

Awesome lol

 

[TheRac25]

doesn't look like much force all at once, looks like most of the energy was released in heat
Ill have to give a tentative nod to the small vent holes

 

[JMarca]

Okay, So, Just to Clarify, Then,
Means I can safely Vape the 0.4 ohm?

Notice the jumps below .4 ohms in the reply below, be extremely careful when you go that low, a mere 0.1 ohm difference can cause alot of trouble.

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

 

[Baditude]

doesn't look like much force all at once, looks like most of the energy was released in heat
Ill have to give a tentative nod to the small vent holes

Did you watch the entire video? (Hint: Go to the 3:55 time mark)

That heat released is hot enough to cause second degree burns requiring a trip to the ER and a plastic surgeon. And that's before the explosion happens.

 

[Enoch777]

I see Baditude and Ryedan are still keeping these novices in check. +1 fellas.

Read what they said. Then re-read it. Then do some homework. Then get the gear you need to do it safely. Finally, after some experience at it, you will have figured out how to vape sub-ohm and know how to do it safely. Thankfully your battery had a 35 amp limit.

If you find your ohms dropping (or raising) while testing the resistance I highly recommend you:
1.) Check for shorts
2.) Make sure your leads are nice and tight, i.e. the screws didn't get loose somehow. It happens occasionally.
3.) Check your contacts to make sure there's a good proper connection

And if it's still not coming out right you may have some faulty gear, like a chunk of wire stuck inside the post because you tightened it down way too hard. I had to throw away an RDA once because of that reason, just saying. A properly installed coil should heat up evenly and come out to the exact same resistance every time it's checked. (With a variation of .1Ω for natural causes such as heat expansion, etc)

Please be careful and vape on

 

[Ryedan]

doesn't look like much force all at once, looks like most of the energy was released in heat
Ill have to give a tentative nod to the small vent holes

It doesn't look like much, but when the cell flames it's giving off gas quite fast and nothing you can do will stop that chemical reaction. With blocked vent holes you've likely got enough pressure build up in a PV for it to become a pipe bomb.

That was however a ICR cell and that's why they are not recommended for vaping. IMR and hybrids don't burn and don't make gas anywhere near that fast, but they are still not safe to vent. That's also why it's always recommended to buy batteries from known good sources so there is minimal risk of getting counterfeit cells.