berger

OK Rocket, you started with the link to the other (cough cough) placed in another thread Here

Im opening up this thread for further discussions on the dangers

My first question is this, why is it stacked batteries appear to be more prone to the possibility of fire and or explosions? Does it have something to do with unbalanced conditions between the two cells that are placed in series?

tibob1

With this situation happening, and reading all about what happened got me to think about batteries. Questions are:

1. Does the C rating play into VV demand for power? For example, if the VV is set at 5 volts using a 2 ohm carto the Amps drawn is 2.5.

If your running RCR123a's (Powerizer C rating is only 1.2 Amps or AW IC 123a C rating 1.5amps) how can it supply the amps drawn at 2.5? Isn't this overdriving the battery?

2. Can overdriving the battery cause thermal runaways? Explosions? Could this be what happened?



(this post moved by mod to this thread for relevance)

slimest

why is it stacked batteries appear to be more prone to the possibility of fire and or explosions?

berger, if "stacked" means batteries in series without a DC-DC step-down converter, I think, they could be damaged because a user could connect a low resistance atomizer to them. I would say - a usual 2.5 ohm heater becomes LR if you connect it to 2 batteries in series. This is Ohm's law: if you have double voltage on power supply, you have to use double resistance to achieve the same current and even more resistance if you want to achieve the same power.
I don't see another reasons why using 2 batteries in series in more dangerous. Users just should follow recomendations about right resistance for their power supplies.

slimest

probably because they are smaller batteries to begin with

Let's count. For example you use a 2 V battery and want to get 2 watts of output power (on your heater). According to formula, this battery has to give current 1A, and heater should be 2 Ohm.
Then we connect two similar 2 V batteries in series and get 4 V output. To achieve the same power 2 watts we have to use 8 Ohm heater (4 times more!), and current taken from these batteries will be 0.5 A - two times less. So you get the same power on atomizer with 2 times less current consumption.
Thereby if you use 2 batteries in series, load requirements are 2 times less in case that user counts and uses an adequate atomizer resistance. If he uses 2 LiIon batteries in series (about 8 volts) with a 2 Ohm atomizer, he can get about 30 watts on the heater. This is has no sense and obviously overloads batteries. And if their voltage drops to 5 volts under the load, they will be ruined soon.

slimest

Seems that I double Rocket's thread about Ohm's law...

berger

By stacked I mean in series with or without regard to a regulator though using a regulator that does bring another factor into and adds to the question concerning safety and loading. I am assuming the output (plus whatever percentage of loss from the regulator) can now be assumed to be the loading or total output of the batteries? For this purpose Im ignoring the loss of any of the other parts such as switches, leds, wire resistances, vibrating motors etc...and looking solely at the atty or carto as the output load.
Also when looking at C ratings of batteries are these ratings based on constant current? are they equally applicable to the method we as vapors are using them in momentary application and not continuous constant drain?

slimest

I am assuming the output (plus whatever percentage of loss from the regulator) can now be assumed to be the loading or total output of the batteries?
If we use pulse DC-DC step-down (buck) converter, current from batteries less than output current the same factor as voltages on batteries and output (of course I don't count efficiency). So if input voltage on converter is say 8 volts and output voltage from converter is 4 volts with current say 2 amperes, current consumption from batteries is 1 ampere (a little more, remember efficiency). It means, that if using a buck converter we help batteries survive.

Also when looking at C ratings of batteries are these ratings based on constant current? are they equally applicable to the method we as vapors are using them in momentary application and not continuous constant drain?
I would say: maximum C ratings are not really maximal, they are recommended by factory in purpose to keep life of batteries appropriate. Of course we must not overcurrent a batteries too much (say 5C instead of recommended max 1C) at all. If we load them with short pulses of current, it is better for batteries than constant current, and we can afford a little more max current.

Oh, not to easy write these things in english..

Teri

You guys are confusing me with the battery technical talk. Can we get a little more simple somehow?
Does what you're saying apply to, let's say, a lavatube? The best it does is that the battery can be charged only to 4.2. Yet, you can dial it up to 6 for vaping. Is that overloading it to the point that it could be dangerous? Wouldn't that apply to any VV pv that you push beyond its battery rating, or are we talking ONLY more than one battery stacked and unprotected?

slimest

Teri, it's my fault, I just have difficulties to explain some things in English. I wrote a small article about basics of using LiIon accumulators, but mostly for phones users. And this article is written with simple, but russian words

About Lavatube. As far as I know, this system has step-up converter, so it eats more current from accumulator than gives to atomizer (vice versa to buck converter). And more output voltage, more currents difference. So you have to use really quality, safe and high drain accumulators, such as AW IMR, some Sanyo high drain batteries etc. In this case you are safe.

Rocketman

Berger,
Thanks for starting this thread. If nothing else it will raise questions, maybe not a lot of answers, but the topic will be fresh in everybody's mind. That's a good thing.

I'll point you guys to JJ's various posts about loaded voltage. Not the most tactful person n the world, but hidden in those posts is some valuable info.

If a cell can't take the load the loaded voltage drops. If the loaded voltage drops, the cell can't take the load. Might work for a while, then the cell gets old. The best outcome is going through a lot of cells because they just won't hold the charge they used to. If performance degrades after 50 to 100 charges, you wore out the chemistry.

and were lucky.

With little batteries like the 16340, RCR123, and even smaller, C rating is important. If the manufacturer isn't brave enough to give it a high C rating, why should you be brave enough to make up reasons to abuse it?

We'll have conflicting posts here just like on the other forum. There will be those that will continue to ignore the risks, and some that will be so paranoid that they won't enjoy vaping.

Don't abuse your equipment, or you could go blind
I hope this thread helps to increase awareness of e-cig safety

slimest

Hurray! Now Rocket will answer

Rocketman

answer hasn't changed much over the past 3 years

KNOW WHICH END IS THE WEAK END.

Teri

Ok rocky, are you telling us that if a battery should charge to 4.2 and it will only charge to 3.8 (or anything other than 4.2) that it's time to get rid of it and get a new battery? I'd rather be paranoid and over compensate than have something blow up in my face and have to have it rebuilt again

Rocketman

Teri,
If your cell performance changes drastically, then it's time to do something.
Could be the charger. It should stop charging at the same point every time.
If it normally charges to 4.20 then 4.15 to 4.25 is OK. (4.25 is a little high)

If the cell used to vape for 10 hours and now you get about 5 hours. SOMETHING has changed.

A charger/cell that should get to 4.2 volts sort of stops at 3.8 volts, then something is wrong. The charger output could have decreased and is taking too long to charge the cell completely.

You have two mods that I made. The Aluminum box mod with the meter and the minibox. If you are having concerns about either of those, for any reason, let me know. I know you had a dirty switch problem a while back, but if the battery performance is questionable, stop using it. Let me know.

slimest

KNOW WHICH END IS THE WEAK END
Golden words. I just add: a problems begin in your head. Always think what are you doing. If something unclear, ask. Better to look blind than to be blind.

Teri

Not having problems with the mods. Just wanted to clarify when to trash batteries. I do check them when they come off the charger. I have one to trash I think. It charges only to 3.8 put back on charger and it charges to 4.1. To me that's a little iffy and I'm not taking chances.
Now, what about my VV question? Can we safely push/ dial up a battery that's reading 3.8 to 5 or 6? It doesn't seem logical to me to be able to do that. Seems to me like trying to put my car on the track in a NASCAR race and not expecting the engine to blow to pieces.

WyldRice

Not sure, but thank you for starting this thread.

I'm very curious because of this AW 18650 Semi-Nuclear Device perched dangerously close to me on my desk.


So I guess I just stick it in my mouth, right?


j/k ...I can see how some noobs are confused, This is no joke! Thanks again!

Keep Vapin' Safely!

Rocketman

Teri,
Vaping at voltages above 3.8 volts can be done in a few different ways.

A single cell and a booster circuit. Draws Extra from the cell. More current drawn the higher you go. Electronics do the magic act. But it does ask more from the cell.

A pair of cells and a buck circuit. Load on the cells is directly related to output voltage but generally less load on the cells. Again has magic electronics in it.

A pair of 3 volt cells, straight through.

A pair of 3.7 volt cells, straight through.

A pair of cells and a linear regulator. Linear regulator just gobbles up the excess voltage.

All of these methods can be accomplished with little cells or bigger cells.
The correct size cell would be one just big enough to handle the load without straining.

Dialing up a VV mod to find out just how high you can get it to go is a little like testing a car to find the top speed cutout (100mph on my Saturn, 141mph on the Mark VIII. Of course tested via software ).

berger

Thanks for the Kudo Rocky,
Im just getting the feeling that this subject is the elephant in the room nobody wants to talk about until something horrible happens. In light of the recently reported incidents bringing the issues to the forefront, I wanted to try and learn and maybe teach others about what is happening here and what we can do to protect ourselves. When I began vaping about a year and a half ago I knew absolutely nothing about electronics and lion batteries. I had no idea that batteries could even explode like that. Sure I heard about the flaming laptops back in 2007 but wrote it off as crappy Chinese QC without learning anything about why it happened. All I cared about was that the lion batteries worked much better in my camera then Nicad did in the old one.
With the introduction of the mods and maybe more so the epower/boss/noego unit I was introduced to the replaceable lion batteries and thens when the real fun started for me and a host of others that didnt have mods prior to that. Since then mods and even mainstream Chinese units with replaceable batteries have exploded (no pun intended) all over the market and I can only see it growing. We as vapors, now more then ever, need to know and understand more about what it is we are dealing with here.
I have a ton more questions and comments about this forthcoming...

Teri

Best I've gotten out of the escape is 110. that scared me enough to back it off.
At any rate, I guess I can be comfortable with the lava tube.

slimest

Can we safely push/ dial up a battery that's reading 3.8 to 5 or 6
Teri, output voltage means nothing, output power means. If you dial to, say, 5.5 volts to load a HV 4 ohm atomizer, try this. If your atomizer is 2.7 ohm, consider if you really want this power. It is too big for usual vaper. If you feel like need some hit, try to increase nicotine concentration.

Rocketman

Knowledge is the key. Smokers were in the dark for many years (thank you Tobacco industry), then came the denial phase (won't happen to me), then the paranoia phase (fourth hand cancer from reading a Malboro ad).

Learn, first hand, get off the video games, search the web for intellectual content.
For those of you in the denial phase and think this single failure is overblown, I wish you a speedy and complete recovery (in advance).

HiRezL

My ePower and NoEgo units both have a vent hole in the bottom, blow-out bottom plug and use a single large protected cell, so that seems to be the best way to do it, according to the detailed accident info over at ECF.

Rocketman

Teri,
How many small cars pulling travel trailers up the Grapevine have you seen pulled over on the side of the road?

That's High Performance vaping with Low Performance equipment.

Teri

we see it all the time Rocky. Idiots that think they're half ton pickup will tow a 25 foot trailer, loaded with a car, 2 motorcycles and other whatnots.