38 replies to this topic

[Digisatman]

It's an old story amongst a lot of people on here, and most things now a days run on Li on batteries,

I have a caravan and everyone says to replace there tyres every 5 years even if only used for two or three journey covering no more than 500 miles. But you don't do that on a car ?

[Fad]

I wasn`t aware of the potential issues with li-ion batteries until I started using PVs - then I realised about the possible problems that may arise with mishandling.

If I wasn`t following different online forums though, maybe I wouldn`t have known about this kind of stuff, and maybe not be so aware when dealing with them.

[clockworks]

Thanks for posting those pics, Paul.
All rechargeable batteries are potential bombs, even the older NiCad and NiMH types. I've seen two NiMH battery packs fail - one during use in an RC car, when the speed controller shorted onto the carbon chassis, and one whilst being charged at 5C. The first resulted in a bunt-out car, the second shot the cell across the parking area.
In both cases, it was "misuse" that caused the failure.

RC people are more aware of the potential problems of lithium cells. There's no advantage to be gained from pushing them too hard (unlike with NiMH packs), so there are fewer accidents with lithium. The widespread use of balance chargers also helps minimise the risks from lithium. It's also a requirement at affiliated indoor clubs to use a LiPo charging sack.

Stacked (series) cells should always be balance charged as a set. Does anyone actually make a ready to use balance charger for individual cells? I've not seen one. My "stacked" mod uses a hard-wired 2 cell pack.

The potential for overcharging is one reason why I don't use a cheapo charger any more.

[DutchVaper]

I was aware of the potential dangers, but i guess it never hurts to point them out.


Also nice write up Trog!, i suspect that is quite often the case when accidents do occur, (although wherever millions of a certian thing are in use, there is always the chance of an real accident sadly)

[Trog]

as someone who has for real charged thousands and i do mean thousands of li-ion cells over the last three or four years used with a modicum of care they are okay..

i have never seen or heard of a cell "exploding" and i am talking thousands of users as well here without some help from the user.. i have also never seen a charger or cell catch fire.. many thousands of test samples here.. we have banks of them running all day..

short circuits are the problem or in simple terms letting the stored energy out too quickly.. an alkaline cell is inherently safer because it cant do this..

i have had one go off in my pocket.. a small single (16340) loose cell mixed up with keys and loose change and me leaning against something that applies pressure to the mix.. entirely my own fault..

it went bang and scared the sh-t out of me.. my pocket caught fire and the contents blew all over the workshop.. it took me several hours to find my car keys..

little bundles of energy.. release that enrgy in a slow controlled way and its okay.. let it go too quickly and it aint okay..

mind you the same principle applies to a tank full of petrol in your car.. we are in daily contact with quite a few potential bombs..

but millions and i do mean millions of li-ion cells are in daily use.. accidents are pretty rare..

balanced charging applies to large bicycle packs and stuff.. pre-wired ones.. but cells should always be kept and use in "groups" old ones not mixed with new ones and stuff.. loose cells will get balanced each time they receive a full charge if charged seperately..

pre-wired packs may not.. i have a bike modding friend who every week or so splits his illegal and over powered bike pack up to check and balance each cell..

folks mod torches electric bikes and e cigs.. not all of them know what they are doing.. the real problem (if there is one) with e cigs is their proximity to the face.. vent holes just turn an exploding one into a flame spouting rocket ship.. dont kid yourself it makes one safe..

"fake" safe is dangerous.. which is the real problem.. folks thinking they know when they dont..

i could write more about this but it soon goes off the front page and gets lost.. it all been said before and many times over.. tis a bit like chinese whispers though.. the internet is.. what goes in aint the same as what comes out..

i am a bit dubious about large 18650 powered devices in the hands of the clueless.. which is one of the reasons we dont sell them.. the bigger the battery the bigger the potential bang.. little cig sized things are basically okay because they are little.. big things not so okay..

trog

ps.. RC stuff isnt the same as e cig stuff.. the exploding battery factor is way higher there.. the "expert" knowledge is also higher.. a cell phone at one end an RC heli at the other end.. one is far more likely to explode or catch fire than the other.. both use lithium battery technology..

Edited by Trog, 09 November 2011 - 10:58 AM.

[clockworks]

You are correct that accidents are rare - fortunately - but they do happen, usually through user error or misuse. Both instances that I've personally witnessed have involved user error.

Single cells from a stacked set are, indeed, "balanced" when they are correctly charged individually. Problem is, it relies on the user remembering to charge each cell completely, on a charger that cuts off reliably at the same point every time. Forget to charge one cell properly, or use a dodgy charger, and you could have a problem. A balancing charger that takes a set of single stacked cells simultaneously solves the problem, as does a multi-channel charger that's properly trimmed.
Are the standard "2-channel" chargers that people use up to the job? I prefer to not take a chance, so I use a charger with a digital display and decent error-checking, and series packs are balanced every time.

[Maz]

I can probably count on one hand the amount of Trogs posts I have +1nd over the years but that one was excellent.

Any of the longer-term vapers will be aware of the potential dangers of these cells, we've gone through the scare-mongering and read the horror stories (not saying this about you Paul, just in general). One thing we've also seen is that you have to search for them and considering the bigger battery devices have been around for over three years now the more serious mishaps are still only a small few examples and they have (AFAIK) ALWAYS involved stacked cells.

I used to use (over 2yrs ago now) a copper @ 6v on a 3.5 ohm atomiser, I really had little choice at the time as they were the only atties available at the time and they just didn't cut it for me on 3.7v. As soon as lower resistances became available I went back to 3.7v on an SD, nothing against 6v before I get lynched but I was happier personally no matter how rare the incidents were.
I very nearly had an incident myself with that copper (regarded as a decent mod at the time, I now think it's a dangerous piece of shit but that's JMO). Mrs and Mini Maz were upstairs asleep and I was downstairs having a sneaky few beers and a few hours alone blowing the shit out of pixels on the Wii with the copper sat on it's end on the table in front of me. I reached down to pick it up and it was damn near red hot, I ran into the kitchen, got a towel, picked it up and at arms length out of the window I unscrewed it and dumped the batts (into the bin next morning). I think the spring was too weak and had got stuck causing a short in the bizarre firing mechanism, I took it apart after that, replaced the spring, made some other modifications and stopped using it shortly afterwards. Up until that point I was perfectly happy with it at 6v.

I've always been happy using unprotected cells too, until I started using 'solid' mods and then things changed again, I started using AW ICRs as they DO have full protection including short protection that a lot of the other "protected" cells lack. A small extra expense for added peace of mind. I don't trust chargers either and never intentionally leave them on when I am not awake/in the house, this may be over-cautious but not bad practise and I'd rather be accused of paranoia than run through a wall of flames in the middle of the night to rescue my son, or worse.

I don't actually think I'm paranoid, the thought of exploding batteries never even enters my mind unless it's brought up, I've just trained myself into behaving this way with Li-Ions. I don't think they are inherently dangerous, they just need a little respect.

Sorry for the inane drivel, I'm prone to it, it just flows and as they used to say on Crimewatch just after they told you about a spleen-eating psychopath loose in your neighbourhood, "don't have nightmares"

[Trog]

from my experience the chargers are basically okay.. i have volt checked a fair few of various types.. once again i have never found one that is far of the 4.2 mark.. most folks will end up using the off the shelf ones and not the specialist ones..

once again most e cigs are single cell devices so the exact voltage the battery gets taken to dosnt matter.. large multi-cell packs that run batteries in parallel are the problem.. not an e cig one.. more souped up electric bikes and stuff..

from my (bike) friend who is into such things the cells are charged in banks.. over time the cut off is governed by the cell at the highest voltage.. some cells get less charge and this build up.. one cell goes flat before the others..

a quick and dirty way around this is not to run the packs too flat.. but this loses "mileage" or range so it aint good.. making good chargers for such packs is expensive.. but this aint an e cig thing..

i leave my chargers going all the time.. so even if i say dont do this i do it myself..

i also tend to charge batteries one at a time.. but whilst saying there is a danger connected with lithium technology a few simple precautions make it basically okay..

part of the problem is what i would call the modern consumer protection society.. we are creating a bunch of clueless buyers who expect everything they buy to be idiot proof.. knives should not be sharp and pointy such things are not safe in the hands of idiots.. maybe large loose lithium cells fit in this category..

the "beware of the dangerous dog" theory notice make a seller reluctant to admit that what he is selling maybe dangerous.. such an admission may make him liable.. my take is simple.. i keep the size of the potential bombs i sell no bigger than i consider they have to be.. i dont like large 18650 batteries so i dont sell e cigs powered by such things.. that on this place makes me a bad guy..

trog

ps.. just to add.. the stacked battery problem wasnt stacked batteries as such.. it was folks stacking the wrong mix of batteries.. 18650 sized devices with no built in short circuit protection.. the so called 6 volt vaping craze and none rechargeable cells being wrongly used.. not just user error here a maker error as well and a forum error cos its forum talk that fires it all off..

used correctly stacked batteries in series are perfectly okay and its perfectly normal.. incorrect clueless use is the problem..

Edited by Trog, 09 November 2011 - 12:02 PM.

[Maz]

Trog, on 09 November 2011 - 11:49 AM, said:

part of the problem is what i would call the modern consumer protection society.. we are creating a bunch of clueless buyers who expect everything they buy to be idiot proof.. knives should not be sharp and pointy such things are not safe in the hands of idiots.. maybe large loose lithium cells fit in this category..

My grandad used to tell me as a kid 'a blunt knife is dangerous as it's likely to slip, keep your knives sharp and your head screwed on when using them'.

Talking about testing chargers Trog, you'll be the man to ask. I only use 16340s and 18350s so I only really use the charger supplied for the SDMkII (Desay) as it's decent, compact and neat, how does it stack up, when that little green light goes on does it completely stop charging the battery or does it continue to 'trickle'?

[Trog]

i used to think they all stopped when the light went green.. but not all of them do.. its not a forever trickle so it isnt that bad..

we looked at some to see exactly what was going into the battery.. its a bit boring like watching paint dry..

there seems to be two types.. some that flickers the light.. they switch off and restart every so often.. a cell voltage test takes pace.. if its lower than the theoretical 4.2 it carries on.. if it aint it stays off.. the flicker or test gets rapid or quicker the nearer the cell is to being charged.. the one we were looking at was still putting about 65 ma into the battery when it switched off or stayed green.. the voltage was close to 4.2..

the other type does it differently.. no flickers or offs.. it just starts off with a fairly high current going into the battery.. kind of like water running down a hill when the battery is flat the slope is steep and the water runs quicker.. quite a heavy current is going into the battery...

as the difference between the charger voltage and the cell voltage gets less the flow slows down.. so it goes from rapid to slow.. in the end very slow.. the last bit takes ages..

at a certain point the light goes green.. the current dosnt stop entirely though.. it is very low at this point and as the cell voltage goes up a smidge more it will eventually stop altogether.. so it dosnt really matter.. such a charger will not over charge the battery.. the so called trickle gets less and less and soon stops..

its more to do with how the charger works than anything else.. looking for the flicker will tell you which sort you have.. technical terms avoided deliberately i never could figure them out.. he he.

trog

ps.. with both type as you watch the paint dry the actual current going into the battery gets lower.. both types put a lot more into a flat battery than they do a half charged one.. the closer to the 4.2 volts the cell gets the less goes into the battery.. its not a linear process..

Edited by Trog, 09 November 2011 - 12:55 PM.

[Maz]

Cheers Trog. The one I am currently using I've had over a year so no need to look there is no flickering, sometimes a dull red light but I'm pretty sure it's not charging at that point. Pulling out and replacing the battery sorts that out.

I have a spare but it's still boxed so god knows, I checked it quickly when it arrived and then reboxed it.

[Maz]

Just seen this posted on ECF, now I'm no genius but isn't this another disaster waiting to happen?

Quote

I use a 3v and a 3.7v stacked in a GGTS and it ROCKS

[clockworks]

Maz, on 09 November 2011 - 05:22 PM, said:

Just seen this posted on ECF, now I'm no genius but isn't this another disaster waiting to happen?

Quote

I use a 3v and a 3.7v stacked in a GGTS and it ROCKS

Well, I certainly wouldn't do it!

[slate]

Please forgive my ignorance , but would the AW IMR 18650 batteries be succeptible to such failures ?

[Dik]

slate, on 16 January 2012 - 06:05 PM, said:

Please forgive my ignorance , but would the AW IMR 18650 batteries be succeptible to such failures ?

The aw imr batteries are aren't lithium ion batteries and are considered to be safe chemistry

[SteveMacc]

IMR batteries can set on fire. If you short them, they can produce a very high current. Some folks think IMR are safe from exploding. What the safe chemistry actually means is the toxicity of the gas when it explodes. Li-ion would exploded sith flames, IMR would just explode with gas.

In addition a protected Li-ion cell will not cause a big issue if shorted. An IMR battery will, as it has no protection circuit and some can produce 70 amps on discharge, Wouldn't want to be around when that happened.

Edited by SteveMacc, 16 January 2012 - 09:11 PM.

[Scorpius]

Shorting IMR batts :

[Maz]

So I don't get it, is it as Steve says that IMRs will explode, or is it as in the vid that seems to show they will get hot but not vent?

There's the usual scare mongering here on ECF that claims this explosion to have been caused by an AW IMR 18650 but we only really have their word for it as everything is charred beyond recognition http://www.e-cigaret...mr-18650-a.html

I'm still firmly in the 'treat batteries with respect and nothing bad will happen to you' camp BTW..

[googled]

Scorpius, on 16 January 2012 - 09:03 PM, said:

Shorting IMR batts :

Boring! I want to see some face melting, head decapitating mega explosions not a battery getting a bit warm.
Seriously though, be careful using lithium batteries, I got a very nasty bump on my head when one rolled off a shelf.