voltage and amps and watts, ohm-I!

[WannaGetHealthy]

Advance apologies if this is in the wrong sub forum. Please move it if it is.

So I've been vaping for a period of time now, and I accrued just enough info to get me where I wanted to be a couple of years ago. All was well until the advent of the RBAs. Now we can make our hot pieces of wire in whatever size and shape we want and I find myself wanting more out of my vaping gear.

I was bottom feeding at the time, so I scooped up an A7 and learned how to wrap my own coils and got my rig working every bit as good as store bought attys (maybe a little bit better). Then I got to eyeing the Genesis style RBAs and decided to give up bottom feeding. I got an all mech chinese telescoping GG knock off and an AGA and learned how to roll mesh pretty well.

Thing is, now that I'm making such economic coils (and the fact thqt I'm not out a fortune if I try something and find it's not 100 % awesome) I can't help but wonder if I can't get more production out of this thing. I never found much use for cartomisers while I was bottom feeding, so I never learned anything about duel coil cartos, but I've run into a few DC setups in gen style RBAs. In addition, I never played around with HV setups once I found that I prefered 4.2 V (3.7s fresh off the charger) with a 1.5 ohm atty over 6v with a 3 ohm atty. With my limited knowledge of the subject, I understand the wattage is about the same in the above comparison, but I liked the all day staying power of the 18650s.

Before I get into anything crazy and unsafe, I figured I'd better ask a few questions.

1) When powering resisters in parallel, I know that you are putting more stress on the battery. What formula do you use to find what value (I din't even know the term) that I can compare to a batteries specifications sheet to know if I'm asking for trouble?

2) What additional concerns should I be aware of if I stack batteries?

Basically, I had the random thought, "What would happen if I stacked 2 rcr123s in this mod with two wicks with a 1 ohm coil on each of them in the RBA?" And I found myself lacking the knowlege to answer that question. If you don't feel like typeing out such info and you know of a link to something I ought to read to make myself more knowledgable, that would be appriciated as well.

 

[jasl90]

1) When powering resisters in parallel, I know that you are putting more stress on the battery. What formula do you use to find what value (I din't even know the term) that I can compare to a batteries specifications sheet to know if I'm asking for trouble?

Easy math... Assuming 2 resistors of equal resistance, running in parallel... The resistance is cut in half. For example... A1.5 ohm dual coil atty is two 3 ohm coils running in parallel.

2) What additional concerns should I be aware of if I stack batteries?

Basically, I had the random thought, "What would happen if I stacked 2 rcr123s in this mod with two wicks with a 1 ohm coil on each of them in the RBA?" And I found myself lacking the knowlege to answer that question. If you don't feel like typeing out such info and you know of a link to something I ought to read to make myself more knowledgable, that would be appriciated as well.

Please don't... If I'm not sure what the max voltage is on a CR123A battery but I'm pretty sure the nominal voltage is 3 volts. Stacking them will give you 6 volts.
Two 1 ohm coils in parallel will give you a total of 0.5 ohms of resistance... The math on that...
6V & 0.5ohms = 12 amps & 72 watts

CR123A batteries aren't designed to go anywhere near that. If you really feel the need to earn yourself a Darwin Award, please do the rest of us a favor and do it without an ecig in your hand.

 

[WannaGetHealthy]

Actually man, it isn't about the wattage of the circuit at all, it about the amps and what the battery is designed to do. I've found the info I was looking for. C ratings, and how that pertains to safely using batteries, and another nifty little piece regarding how stacked batteries don't nessicarily share the load equally.

A genuinely friendly suggestion: thank you for attempting to answer my question, but you gave me the wrong information. When we are answering questions here, esspecially when the question has to do with safety, it's probably best if we make sure we have the right information available. I know answering questions on here gets tiresome sometimes, which is why I am no longer as active on the forum, but if you don't know and don't care to double check the question and your info, just let someone else field the question. Yes, the situation described above could cause battery failure, but your explanation doesn't show why, it only muddies the water further.

 

[meatsneakers]

He was correct. Re-read his answer.

 

[vapdivrr]

not active on the forum anymore?

 

[jasl90]

Out of curiosity... What exactly did you see in my last post that looked incorrect?

 

[sawlight]

Advance apologies if this is in the wrong sub forum. Please move it if it is.

So I've been vaping for a period of time now, and I accrued just enough info to get me where I wanted to be a couple of years ago. All was well until the advent of the RBAs. Now we can make our hot pieces of wire in whatever size and shape we want and I find myself wanting more out of my vaping gear.

I was bottom feeding at the time, so I scooped up an A7 and learned how to wrap my own coils and got my rig working every bit as good as store bought attys (maybe a little bit better). Then I got to eyeing the Genesis style RBAs and decided to give up bottom feeding. I got an all mech chinese telescoping GG knock off and an AGA and learned how to roll mesh pretty well.

Thing is, now that I'm making such economic coils (and the fact thqt I'm not out a fortune if I try something and find it's not 100 % awesome) I can't help but wonder if I can't get more production out of this thing. I never found much use for cartomisers while I was bottom feeding, so I never learned anything about duel coil cartos, but I've run into a few DC setups in gen style RBAs. In addition, I never played around with HV setups once I found that I prefered 4.2 V (3.7s fresh off the charger) with a 1.5 ohm atty over 6v with a 3 ohm atty. With my limited knowledge of the subject, I understand the wattage is about the same in the above comparison, but I liked the all day staying power of the 18650s.

Before I get into anything crazy and unsafe, I figured I'd better ask a few questions.

1) When powering resisters in parallel, I know that you are putting more stress on the battery. What formula do you use to find what value (I din't even know the term) that I can compare to a batteries specifications sheet to know if I'm asking for trouble?

2) What additional concerns should I be aware of if I stack batteries?

Basically, I had the random thought, "What would happen if I stacked 2 rcr123s in this mod with two wicks with a 1 ohm coil on each of them in the RBA?" And I found myself lacking the knowlege to answer that question. If you don't feel like typeing out such info and you know of a link to something I ought to read to make myself more knowledgable, that would be appriciated as well.

OK, lets dissect this a bit more.
At 4.2v with a 1.5ohm coil, you are at 2.8amps and 11.76watts.
At 6v with a 3ohm coil, you are at 2amps and 12watts.
I don't see much difference here, other than your batteries should last longer in the later setup.
For question one, you need to read this, Series and Parallel Circuits, as stated above, you will have a .5ohm load, so 6v into a .5ohm load you get, as stated, 12amps at 72watts. Online Conversion - Ohm's Law Calculator
Which equates to mystuffblewupism!

I'm not a fan of stacking batteries, I come from the flashlight world, I've seen a lot of wild thing's happen! Two mismatched CR123A's, BOOM! Two mismatched RCR16340's, BOOM! Pull any and all above the "C" rating, which isn't 12amps BTW, and BOOM!
The dual coil cartomizers you read about are in a parallel circuit, not series, it's still a hard load, and you don't get something for nothing this way, but anything in the sub ohm load needs to be done carefully with understanding of the loads and output currents of the battery/batteries being used.

 

[pdib]

Yeah, so, some of us were finding that certain 18650 batteries with lower mAh ratings had high C ratings; in particular the AW imr 18650 1600mAh (24amp max continuous discharge) and the MNKE 18650 1500mAh (20amp max continuous discharge)

 

[meatsneakers]

I'd say it has a vapable voltage until 7 or 8 amps.

As for the MNKE, I have yet to see a test. Battery manufacturers aren't exactly renowned for their spec sheet honesty.

 

[pdib]

"I have tested with discharge currents up to 20A and the battery handles it without problems."

^This is the text under that graph. Test of AW IMR 18650 1600mAh (Red)

 

[Covert]

For the sake of messing around (i'm not to brilliant sometimes ) and trusting a good friends wrapping I have stacked batteries and at dual sub 1 ohm levels at something to the tune of 86 watts ........ Would I do so knowing what I know now........ Not in a million years... Way too much to go wrong way to quickly.

 

[meatsneakers]

Yes, 20 amps, at a terrible vaping voltage. And would you tax a battery that hard an inch from your face?

edit-
It seems people are forgetting the incidents that happened last year with exploding batteries. IMR is safer but there is still a chance of a mishap as it doesn't take much explosive energy to knock a tooth out or heat to light your house on fire. These "86w" attempts are going to go wrong one day as I keep seeing people bragging about .3 ohm coils, etc.

 

[pdib]

I'm pretty sure OP was looking for the term "C rating" because he wanted to design good vaping builds; not ridiculous 70+ watt setups. Even my .5Ω setup pushes the 6 to 10 amp rating on many of the batteries we use. (Yes, it is .5Ω on paper, less device resistance; but one ought to err on that side to be prudent.)

 

[WannaGetHealthy]

It's not that the answer contained incorrect information, BUT the answer I needed wasn't really in the reply. It didn't contain the info that I needed to make good judgments when considering the safety of a circuit. The answer I needed was this:

Calculate the amperage the circuit will demand (V/R), then calculate the max safe output for the battery(ies) you intend to use (take the capasity of the battery in mah, divide by 1000, mulitply by the C rating for the battery) and see if the battery (ies) can even come close to handling the load. Then on top of that, consider that battery manufactorers don't always give you the most accurate specs for thier batteries. Finally, know that while you can get more power from batteries in series, you can NOT get more current. IOW, the amps don't get added.

 

[jasl90]

It's not that the answer contained incorrect information, BUT the answer I needed wasn't really in the reply. It didn't contain the info that I needed to make good judgments when considering the safety of a circuit. The answer I needed was this:

Calculate the amperage the circuit will demand (V/R),.

I did calculate the amperage. My bad for not supplying the formulas used. I just didn't see the point since a quick Google search will find you several Ohms Law calculators...

then calculate the max safe output for the battery(ies) you intend to use (take the capasity of the battery in mah, divide by 1000, mulitply by the C rating for the battery) and see if the battery (ies) can even come close to handling the load. Then on top of that, consider that battery manufactorers don't always give you the most accurate specs for thier batteries. Finally, know that while you can get more power from batteries in series,.

Great advise but unfortunately it can be very difficult (if not impossible) to find a good data sheet on a specific battery. Giving you that advise could have just as easily sent you on a wild goose chase.

you can NOT get more current. IOW, the amps don't get added.

Yea... actually you can... and yea... actually they do... Current (amperage), as you stated earlier, is calculated as I=V/R.
When you put two 3 volt cells in series you double the voltage to 6 volts. By doubling the voltage you do in fact double the amperage.
3/0.5 = 6 ... 6/0.5 = 12

 

[sawlight]

I still see no reason for the question. Vaping at 82 watts isn't going to to give you any flavor at all, just a burnt taste. Any realistic vaping wattage, 20 or below, isn't going to push the C rating of any battery to it's limits.
I also don't see any usable coil being able to handle that amperage without popping, if not insta-flashing! I don't see 28-32 gauge Kanthal taking the 12 amps we are talking for any amount of usable time! Nor do I see any usable point to it.

 

[WannaGetHealthy]

Yeah, I misstated that last point. Yes the amprage of the curcuit increases, but the amp discharge capacity of the batteries doesn't get added togerher. IOW, if a single battery can discharge 20 amps (the newest aw 18650 imr] if you stack 2 of them, they can still only handle 20 amp discharge.

Regarding the lack of spec sheets for a lot of batteries: yeah this can be a problem. Going forward I won't be using batteries that I for which I can not find a believable spec sheet. Discharge C ratings are pretty important.

I hope I didn't come off as a jerk, as I truly appreciate your effort to answer my question.

 

[WannaGetHealthy]

Sawlight: the hypothetacle scenario in the original post was merely suppose to illistrate my ignorance of the subject. Nothing more.

 

[sawlight]

Sawlight: the hypothetacle scenario in the original post was merely suppose to illistrate my ignorance of the subject. Nothing more.

Fair enough, I'll leave well enough alone then!

 

[Rader2146]

Sawlight: the hypothetacle scenario in the original post was merely suppose to illistrate my ignorance of the subject. Nothing more.

If you are ignorant of the subject then you have no business castrating and dismissing a technically sound and accurate answer like you did in post #3.

Just because it wasn't the answer that you were looking for doesn't make it (your words) "wrong information".

If you came here seeking knowledge......you're doing it wrong.