Volts, Ohms, Amps and Watts Explained

[degnr8]

So here's a question from the math illiterate on something I've actually been wondering about. I have a bunch of mechs I made before I discovered 5v years ago. I've figured out that with my 510s (which I believe are 2.5 ohm) 5v is pretty much the sweet spot for me. Now I can follow v2/R=w and figure out that that set up gives me 10 watts. I don't know how to use that formula to calculate what resistance I would need in order to get 10 watts out of 3.7V. Would it be the formula on the bottom left? Can't copy and don't know how to do a square root symbol (or figure out a square root for that matter)

 

[CommaHolly]

Thrasher" data-source="post: 9960687" class="bbCodeBlock bbCodeBlock--expandable bbCodeBlock--quote js-expandWatch">

constantly with the overload of math related to vaping. funny how it didnt matter until we got a button to change the voltage.


while i think knowing limits is a good practice in the end you connect the atty turn down the device a bit and slowly adjust til it works for you. no calculator needed - promise.

if using VV a good rule of thumb is resistance + 2 for voltage then adjust up or down.

1.8 ohms + 2 = 3.8 V adjust a click or two for your liking.

this is my formula Been using it for some time now

 

[AttyPops]

You know the voltage (3.7) and the watts (10) that you think you want.

And you want to know the ohms to get. So you need an R = E something P ish formula. So...bottom one under the ohms stuff.

resistance = voltage squared divided by watts or R=E²/P

So 3.7 x 3.7 / 10 = 1.369 ohms. Theoretical.

You can try this too:
http://www.ohmslawcalculator.com/ohms_law_calculator.php
plug in any two known values. However, lately it seems to be messing up with the 1st time so double check by doing it again. I need to find another one. Maybe my browser, IDK.

 

[AttyPops]

this is my formula Been using it for some time now

Annnd.... the theoretical answer is 1.3 or 1.4 ohms...not 1.7. But hey, not picking on ya! That method DOES get you into somewhere around the ballpark's parking lot.

 

[degnr8]

Very nice, The wheel along with the calculator helps me grasp it too. You've also answered the underlying question. Yes I can get the experience I want with a mech and RBA. Good to know as I like to be as self-sufficient as possible with my vaping. Getting a little off topic now I guess, but I'm noticing everybody talking about sub 1 ohm which seems like it would be way too much if it was all just the variables we've been discussing. Would that be because the lower resistance doesn't produce as much heat at the same wattage??

 

[AttyPops]

You can if you can wind/buy that ohm coil.

Re: SLR

They use thick wire. So technically its the wire thermodynamics I would guess, because if they used thinner wire at that low of a resistance it would either be too hot or simply melt.

I don't know if that makes sense, let's try it another way. You could try to use thin wire an .8 ohms, or thick wire at .8 ohms. The thin stuff would be much shorter than the thick stuff. It would still produce a lot of watts due to it's low resistance. However the thick wire is longer due to it's better conductivity for a given length. So...it can take the heat and spread it around.

Basically, you need the watts to heat the heavy wire that you use because you want to try to dump a lot of heat in a larger surface area so you can run around and proclaim you have the greatest vape as compared to those "stock" people!

However, maybe until you A) get a multi-meter if you don't have one and B) get more used to this ohm's law stuffis and C) do a bunch of research and D) make sure you use safe (like IMR) batteries...you could try a standard LR setup 1st.

So watts are watts for a given resistance but thermodynamics are...even spookier.

 

[degnr8]

Oh yeah, I don't plan on jumping into the really tough stuff right away. Was just trying to figure out if it was worth keeping my mechs.

 

[AttyPops]

Sure. Just think 1st, ask questions, and vape on. Use safe batteries. You could consider a vape-safe fuse too if the specs are in line with your intended watts and it fits in the mod. Check vents. Check for shorts.

The thing with the SLR stuff.....is that it pushes everything (battery, button contacts, coil ohms) to their limits with little or zero safety features other than trying to use batteries that vent slowly. Shorts are very bad things. "Hot buttons" are common conversation items. Etc. And frankly, I get OK vapes with standard range stuff. And can even use electronic tech like VV. So Meh.

For those that love them, or want to repair them while sitting in a fallout shelter during the zombie hoard attack....they're great. It's hard if not impossible to do SLR with current electronic PV limitations/protections.

 

[Cool_Breeze]

Katya is looking for posts to add to some stickies and we're working on a textual description of stuff. I've "paused" on it trying to get more input and help.

Anyway, we could use your chart (quoted with credit to you) or your help in editing/updating it. It's here:
http://www.e-cigarette-forum.com/fo...1-etc-filler-type-cartos-862.html#post9804049

Just quote the post and add stuff to the quote (maybe in a different color for that one post you're making.) Or just paste in the chart above or a link to it.

Nice chart. Can we use it, credited?

Thank for the earlier heads up on the formula.

I'm a bit confused, if you hadn't noticed. I'm not sure I understand your post. I understand 'Stickies,' (e-cig technical?) but the reference to the 'Burning Cartomizer thread' is throwing me (unless you were just referencing your text there). Can you restate what you've said or somehow fill in a little?

What colors would you like?

 

[degnr8]

Sure. Just think 1st, ask questions, and vape on. Use safe batteries. You could consider a vape-safe fuse too if the specs are in line with your intended watts and it fits in the mod. Check vents. Check for shorts.

The thing with the SLR stuff.....is that it pushes everything (battery, button contacts, coil ohms) to their limits with little or zero safety features other than trying to use batteries that vent slowly. Shorts are very bad things. "Hot buttons" are common conversation items. Etc. And frankly, I get OK vapes with standard range stuff. And can even use electronic tech like VV. So Meh.

For those that love them, or want to repair them while sitting in a fallout shelter during the zombie hoard attack....they're great. It's hard if not impossible to do SLR with current electronic PV limitations/protections.

Yeah, I'll try the saner ohm levels first and see if I need to go lower for the zombie apolocalypse lol

 

[Startle]

Great post!

It really puts the electrical aspects of vaping into perspective!

Vape On!

 

[xwarp]

I guess I'm lucky to work with equipment such as a HP3457a DVM that can read down to micro-ohms......

 

[AttyPops]

Thank for the earlier heads up on the formula.

I'm a bit confused, if you hadn't noticed. I'm not sure I understand your post. I understand 'Stickies,' (e-cig technical?) but the reference to the 'Burning Cartomizer thread' is throwing me (unless you were just referencing your text there). Can you restate what you've said or somehow fill in a little?

What colors would you like?

Just stashing the text in the Burning Carto thread for now (Katya's domain). We'll probably break it up and make it a sticky with several posts or something. It's a rough draft.

Colors: IDK. Something that shows what you added/changed in a post. Blue and black already taken so pick one at your discretion.

She's indicated that she would like more stuff from other posts.

It all started when we replied to YAOLP ....(Yet Another Ohms Law Post...) and we commented that "there should be a sticky". The intent is to collect stuff since there's 1000 posts about it. However, once one gets started writing, it kind of snow-balls. So I threw a bunch for stuff at it, but it's only a 1st draft, is incomplete, and doesn't contain much of other-people's stuff yet. So we need to beat it up and include stuff. Your chart in particular, but other stuff too.

Somehow we need to organize it too. Maybe summary->moderate detail->more detailed. IDK. And she wants vaping specific stuff. Like "Dual Coil Cartos" which always mess people up. And RBA maybe SLR stuff. It's a challenge because IDK how to organize it either. There has to be text, not just formulas. But people don't want to read a lot of text either.

And as soon as there's a simple rule like "add 2 to ohms and you have approx voltage" there's an exception also...like for DCCs. I guess the sticky is there for people that want to UNDERSTAND what's going on. Some don't want to...they don't have to read it. For those that do, they need it organized and edited a lot better than what it is now. I just threw a bunch of text at it in an attempt to explain, but it's far from polished.

ALWAYS CHECK FORWARD TO MAKE SURE YOU HAVE THE MOST CURRENT VERSION. The "current version" is the most recent one posted.

Here's an "updated" link...current for the moment:
http://www.e-cigarette-forum.com/fo...1-etc-filler-type-cartos-865.html#post9962545

 

[Oaken007]

Ok, so yes, I don't understand. I'm a girl, I'm super bad at math. Always and forever.

If my atty/carto is 2.6... shouldn't I be matching my battery to that (what is this wattage?? Why do I care?)

I switch between 3.7 and 6 volts. One Carto tastes great on six (that's the 2.6ohm Carto) and the other Carto tastes horrible and burnt on 6v. I'm assuming the other one is a LOWER RESISTENCE?? Is that correct? Or is it higher?

I want to be able to buy the cartos I like, over and over again without thinking. Why can't I just do that? Why do I have to figure out all this stuff?

 

[degnr8]

You really don't have to Oaken. If you know which cartos tast good at what voltage that's all you really need to know. Just treat your voltage like you would a volume knob. If it's too cool turn it up. If it's too hot turn it down. The only people that really need this theoretical stuff are the ones wrapping their own coils

 

[Oaken007]

Ohhhhh now I see with your cold/hot analogy! But I still don't know which cartos to buy consistently. LR or HR or SR? I just throw them out if they don't taste good.

Dual Coil vs Single Coil? (Does Dual Coil kill your battery faster?)

 

[degnr8]

Well, you said you like your 2.6 ohm attys at 6 volts. Since most PVs won't go higher than 6 you want to keep the resistance on your cartos at 2.6 or lower. If you go lower resistance, then you will naturally use lower voltage to achieve the same result. With dual coil, the resistance listed is per coil, so if you get a 1 ohm dual coil atty it will actually have 2 ohms resistance which should taste good to you at less than six volts. If you get 1.5 dual coil it's actually 3 ohm which would require more than the 6 volts you like to get the amount of power through the coil that you're looking for. As far as the effect on your battery life, it really depends on your device and how it's getting the VV. Long story short, the difference if there is one will be pretty negligible.

 

[Oaken007]

Sweet, you explained it perfect to me.

I have a Silver Bullet, and I am using the 3.0v RCA 123's when I can. Also use my 3.7v 18650 battery.

 

[Mad Scientist]

I guess I'm lucky to work with equipment such as a HP3457a DVM that can read down to micro-ohms......

Go old school. I have a 3456A using standard 4 wire setup. Has these old fashioned "7 segment led whatchamacallits" from the good old days (got rid of my Nixie tube displaying stuff years ago and now regret that). They actually produce photons instead of just messing with them through crystals and polarizers and whatever whatnot is the latest and greatest. Way more accurate than useful for coil purposes lol.

 

[Cool_Breeze]

Well, you said you like your 2.6 ohm attys at 6 volts. Since most PVs won't go higher than 6 you want to keep the resistance on your cartos at 2.6 or lower. If you go lower resistance, then you will naturally use lower voltage to achieve the same result. With dual coil, the resistance listed is per coil, so if you get a 1 ohm dual coil atty it will actually have 2 ohms resistance which should taste good to you at less than six volts. If you get 1.5 dual coil it's actually 3 ohm which would require more than the 6 volts you like to get the amount of power through the coil that you're looking for. As far as the effect on your battery life, it really depends on your device and how it's getting the VV. Long story short, the difference if there is one will be pretty negligible.

The explanation of dual coil cartomizer resistance at the bottom of the linked page seems different.
Undestanding resistances, LR and HV