k, Im using panasonic ncr18650pd 18650, says 10amp on the site. think its safe to use with a .4 coil? Used it today for a bit and it sames fine, battery isnt getting hot. Just want to make sure im safe thanks
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Yeah, Atty! like was posted, And I said "largely the same thing" not "the same thing" so don't strawman.
Oh, no wait - that was posted on a different thread and the poster was hiding behind semantics, although not well, since "straw man" is two words and a noun. Sorry for the interruption.
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Depends on the actual voltage across the coil when it's fired--measure it with your multimeter...carefully. One lead on each coil screw (assuming a single coil). Current = voltage/resistance
It's ok but you might see better performance from a super high-drain like the AW 1600 or Samsung IMR. But the PD is good for 10A continuous and 18A burst, so you are fine.
Well, by seeking actual information and reading it, and not running around like a chicken without a head screaming bloody murder. Issues with stacked batteries have almost always been because of the interaction between the two batteries, not because of a high discharge rate related to the load.
Interaction of the batteries is what I'm talking about. See last stuff below.
You continually cry that it's "nearly a dead short" and you hide behind the fact that you didn't say it was a short.You clearly intend people to conflate that particular resistance with a dead short. It's not even close from a number of perspectives, so that blanket statement is false.
I intend no such thing. You didn't read/interpret it properly.
High discharge rate does NOT lead to internal shorts!!! That is a flat out irresponsible statement to make. And fuses do nothing to protect against internal shorts.
Internal to the battery or the PV? Anyway, fuses protect against external over-amps...of course. Never said anything else. Are you....making this up as you go along?
The thought process is: High discharge = hot battery. Heat leads to electrolyte breakdown which leads to internal shorts. That's also why you can't charge them super-fast like NiMH for example. The irresponsible statement to make is that there is zero danger. Not the "use caution and think" type of statements I'm making.
It doesn't matter nearly to the degree you make out, and that statement is not true by itself. There are many variables you are not specifying that change the picture completely. Resistance doesn't matter on regulated mods with regard to battery stress. A super high drain battery or battery pack wouldn't be stressed by that load.
21 amps and it wouldn't be stressed? The manufacturers probably disagree. Too late for me to look it up and it's a generalization anyway without a specific battery spec.
Excessive heat degrades these batteries. Most manufacturers caution against overheating them for a reason. But I guess you know more than they do. And now we have to cherry pick with "super high drain" vs "high drain". See, that's where it gets confusing for people. And you're altering/qualifying stuff now with "super high drain"....
Please show your work how you applied ohm's law to what you said.
No, I'm correcting gross misinformation and hysteria. Your being badly wrong does not make the person who corrects you a troll.
Work/explanation:
Stacked batteries have double the voltage of a single cell. Given a load at X volts vs 2X volts, the 2X one pushes more amps. Amp limits DO NOT STACK when stacking cells. So if a single cell has a 10 amp limit, the stack has a 10 amp limit, even though the voltage goes to 2X. See?
So higher voltage (AKA using stacked batteries) pushes more amps than lower voltage for a given resistance. And when there's a short it's extra nasty. This is due to basic ohm's law of I = V/R. So when V is 2x, I is higher. See? Simple.
So that's one main reason why stacking batteries is frowned upon in mechs these days.
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The unprotected ncr18650pd handle like an ICR battery. See post #27 in this thread. I would not use these in a PV.
That's just incorrect and misleading. Short circuiting a battery, especially a lithium of any chemistry is a *very* big deal. You want to avoid it all costs. Short circuits will damage the battery whether they result in an immediate internal short or not. Considering the amount of energy stored in these batteries they deserve a great deal of respect regardless of the plate chemistry that is used.
Oh, and yes batteries are tested for short circuit... to destruction. The purpose is to observe the failure mode, not to prove that it is safe to do so. Your car has probably been tested and will have a safety score. That doesn't meant that it's safe to crash into a wall at 60mph, it just means that you may live, if the safety rating is high enough.
Take a little further, say your car has the new auto breaking safety system, is it safe to drive it at a wall? Is it something you should do? Safety requires a modicum of common sense to go along with it.
You are kidding, right? This is so far away from what we need to be telling people...
The "shutdown" mechanism for a lithium battery is a polymer that melts when the battery gets hot. The polymer permanently coats the plates and prevents the plate material reacting. People who thinks that "shutdown" means you are instantly safe or that the process is reversible are misinformed. This is perhaps not helped by the misleading terminology that seems to imply that is the case.
Note that the battery is already extremely hot by this time. If one or more of the plates are damaged through previous short circuits, physical damage, overcharging, or charging at sub-zero (C) temperatures, then there is no certainty that the short will not result in thermal runaway. There's some rather interesting but by no means comprehensive information here.
Considering that we don't even know what the "baseline risks of vaping" actually are, I suspect this is largely a fallacious argument. Battery safety is something that we should be extremely concerned about, especially since battery damage can be cumulative. The best we can say is that at some point in an abused battery's life it is going to fail. How it fails and under what circumstances is largely a matter of chance, however it's usually at a point of greater stress.
Please see above.
I actually wonder how many have actually occurred but the perpetrator realises they have been a Richard and quietly bins the evidence? Add to this, the short may not immediately result in thermal runaway but simply leave the plates in a damaged condition; Actual failure could occur later when the battery is charged and some other dangerous event happens such as dropping or overcharging.
It is unlikely that any one single event causes an instant battery failure. That batteries fail immediately when put into a stress situation just indicates that previous damage has occurred. The complete history of the battery needs to be examined to determine the real reason the battery failed, but events that we should be avoiding do indeed include short circuits.
You continually cry that it's "nearly a dead short" and you hide behind the fact that you didn't say it was a short.
Actually... while it's hard to define "Nearly" in battery terms, I think this qualifies. The reason is that the internal resistance of IMR batteries is likely to be in the range 0.1 to 0.2 ohms, which means that up to half the heat generated could be occurring on the plates (and that is the crux of the matter when it comes to deciding whether or not it's a good idea to short any battery).
ICR chemistry batteries will most likely have an internal resistance of 0.25 ohms up to 0.5 ohms, which is one of the factors that gives them a lower C rating.
Actually, you need to seriously re-think telling people it's safe to short out any lithium battery. Safety is never irresponsible, but the opposite would appear to be true.
Thanks for the newsflash.
Pot. Kettle. Black.
I think you should apologise to Vaslovik for ripping into her like that. She was not arguing with you.
"Burst mode" in electrical engineering needs to be defined to be meaningful, in other words check the specs. They could mean anything as low as a few hundred milliseconds. You could actually be exceeding the design specifications of the battery, and the C rating declines with aging capacity of the battery.
It's also true that higher discharge rates age a battery faster.
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I have tried sub ohm, and like others have stated it is NOT for everyone, if you enjoy it and are being safe and are not suggesting others try something stupid that can get them hurt, go for it.
I don't care for the hot vape it gave me, or the lack of flavor. Also I did go through more juice and more batteries in a day.
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I would like to know what measuring device is most commonly used to build subohm coils?
Just how repeatable is the winding process, in coil ohms?
or percent 5%, 10%?
and
What loaded voltages, at the coil, are people getting with their batteries?
Just how repeatable is the winding process, in coil ohms?
or percent 5%, 10%?
and
What loaded voltages, at the coil, are people getting with their batteries?
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...............
Really folks, not trying to be mean, just wanted to know what is the most common meter (or ruler) used to measure .2 or .47 ohm? It's not like I asked what it the total path resistance of your mod, including cell resistance, and what percentage of energy is consumed by your mod and not the coil. You know, the I squared*R losses. (I have a hard time getting total loop resistance under 60 milliohms, excluding coil).
Now, that would be mean
Now, that would be mean
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I never go below .8Ω in a genesis with mesh. My absolute favorite vape (ever) is a .8Ω coil with mesh in a DID with a good mech. Why? It's so smooth and the flavor is exquisite. To me it's good enough to mess with having the keep the dang thing upright all the time LOL. With a .8Ω coil and a 18650 batt, I can get a quality vape for most of the day. I use different devices and rotate throughout the day though. I have a kayfun lite that goes with me out and about when I don't want (or can't) to worry about it's position but here at home, I reach for the subohm and mech.
I use a multi meter to check volts and ohms. The winding process will leave me a resistance about +-4% repeatable. I have checked the voltage under load a couple of times and if I remember correctly it was around 3.70 V with that charged battery and my 0.6 ohm coil on my mod. 23 watts, 6 amps. That is about as high as I like to go on that build.
Ryadan,
Thanks, sounds reasonable. What model meter, and would it's cost be within the range of the typical e-cig experimenter?
So while im here, can some of you sub ohm guys tell me exactly what battery I should be using, research a bit and asked and thought it was cleared my panasonic would be good to go but guess not. brother has to order batteries and I want to make sure next time we actually get good safe batteries for mechs
I use AW 18650 IMR 1600 mAh just because they have one of the highest continuous amp ratings, (24A). Just from reading on here heavily, I want to have as much breathing room as possible. Yes I'm new, but I've been rebuilding for about 3 months, lurking for six without an account and safety is a huge thing for me.
just looked again and the PD is the protected version. regardless still want to know the best safest ones for my brother. guessing the aw IMR 1600?
I plan on running .8ohm -1ohm in my mech and will most likely have my brother do the same.
for the love of all thats holy, find a few sites that say they are protected, a new listings that say unprotected, some people saying protected on forums and other not. its a nightmare lol
No this is not a main reason. Stacked batteries are not used with subohm setups, this is not the failure mode of stacked battery mods. Stacked batteries simply don't work with subohm. This is not a subohm issue.
Also, it's time to kill your 21 amp figure, you will never get 4.2v through the coil from a single 18650 with a .2 ohm setup. Regardless of that, the basically bog-standard AW 1600 18650 is rated for 22A continuous. There's nothing special about these amp figures per se.
Well that settles it, some random person on the internet said it.
Remember what we're talking about here, a functioning subohm atomizer is being called the equivalent of a potentially damaging dead short. As far as modes of abnormal operation, the external short is the least dangerous and likely also the least damaging. Not the least reason for which is it's reversible.
No they are not, if the battery vents, catches fire or explodes, it does not pass the test.
I'm not telling "people" anything, I'm addressing a person who is ranting hysterically about short circuits. Unhinged misrepresentation does not help the cause of education.
We know quite well what the baseline risks of vaping are with regard to batteries. What I'm talking about here are non-operational-drain related risks, of which there are several. All of them are more likely to happen than a problem with a working subohm setup.
When you have mod explosions with injury, the evidence doesn't get binned easily. That's kind of the point. It's rare to begin with and when we look at what happens, it's never been because of subohm.
IMRs and other modern high drain batteries have internal resistances well under 0.1 ohm. There's a reason these batteries don't get hot firing .2 ohm loads and below.
I never told anyone it's safe to short out a lithium battery. I don't use the s-word. I just said it's not the risk of blowing a face off that the poster is making it out to be.
Proper high wattage should not be hot or lacking flavor. It will have more flavor if anything.
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