38 replies to this topic

[paulharman]

Hi all,

So a lot of us use Li-ion batteries (mainly 18650, also 18500, 17500, 14650, 14500, 14430, CR123, CR2) in our ecigs, but I wonder how many people are aware of the dangers of Li-ion batteries?

Now I'm not an expert by any means, and I'm sure there are some people on here who will know a lot more about the subject than myself, but I am aware of the dangers and try to take precautions to prevent any injuries!

So lets start by showing what *can* happen in the worst of scenarios. Essentially one of the batteries failed, releasing the contents in to the sealed tube which made the pressure build and the end cap shot off like a bullet.




This was caused by a few factors.

1) The flashlight was a multiple cell flashlight. It had 3 18650 batteries I believe. The user did not check that the batteries had the same voltage before use. Bad idea!
2) The cells had been over-discharged. Bad idea!
3) The cells had been left on charge overnight and most likely were over charged. Bad idea!


Now this mainly comes down to the fact that he did not have a multimeter. When using Li-ion batteries, you really do need one to check the voltage before and after charging.

Without going in to the details of why (I must admit I am not aware of the chemistry side of things) but:

- Do not discharge the battery to under 3.5v
- Do not charge the battery to over 4.2v
- Do not use batteries of differing voltages in a mutli cell device.
- Do not charge faster than 1C (in 1 hour)

The reason that people are warned not to leave batteries charging overnight is two fold. Firstly, when they go bad, they *can* vent with a flame. Protected batteries should prevent this from happening, but Id personally prefer not to put my trust in a cheap chinese pcb. Secondly, the chargers are supposed to cut out at 4.2v. Some (a surprisingly high number) don't. When they get to 4.2v, a lot will start to trickle charge the battery - this is still charging. Any battery which is charged much over 4.2v should be discarded (appropriately of course), and not used. My current charger cuts out at 4.24v. I have just ordered a new xtar and will be putting my current charger in the back of the drawer for emergencies when it will be monitored for voltage.

The Pila IBC is reputedly the best of the plug and go style chargers (not including the hobby chargers they use for rc planes etc), but quite expensive. Another which has been recommended is the Xtar charger. A good review of this charger is found here.

I have seen these recommendations. How true they are I do not know, but it should give you a starting point.

Quote

best unprotected 18650:
panasonic ncr18650a

best protected 18650:
AW ICR18650
WoW 18650

best plug n play charger:
Pila IBC

best hobby charger:
Schulze next-2x7-280-eco

A lot of this information is from the CPF forum. A very good read for anyone with a Li-ion battery would be http://www.candlepow...mparison-chart. Please do take the time to read at least the "Use/safety of Lithium-Ion and charging guidelines" section.

So this brings me to my poll questions. Firstly, were you aware of the possible safety issues of 18650 and other li-ion batteries? And if not, now that you are, do you think suppliers should give better guidelines to their useage?

Edited by paulharman, 08 November 2011 - 09:33 PM.

[Stalker]

Useful information. Cheers for posting this Paul.

That coffee maker has seen better days!



:-) EDIT: Don't these high end torches have vent holes to prevent this from happening?

Edited by TheStalker, 08 November 2011 - 09:47 PM.

[paulharman]

Definitely! Guy got a nasty shock I bet, and now cant make his morning coffee lol

[Neozero]

In answer to your questions:
Yes, I'm fairly battery-savvy regarding l-ion's
Yes, I use a regulated charger that cuts off (at 4.19v on testing), because I use unprotected batteries in two devices.
No, the devices with unprotected batteries in don't over-discharge, they cut off before that happens. Devices without this facility get protected batteries.
Yes, every device I have is vented. I only own one that wasn't at manufacture (A Cree torch). I promptly created vent holes in that myself.

Hoping I ticked the right battery awareness boxes there?
Note some blood was spilled with your torch incident

[paulharman]

Good to hear! Reason for the thread is I have a colleague at work with a cree torch which he uses for biking. He wasnt aware of any dangers and always left his batteries on charge overnight. So I thought I would see how aware people were.

Yeah the chaps finger was injured by the incident

[steve321]

would this happen with a provari?

[Neozero]

He's lucky it didn't take an eye out

[paulharman]

Steve I believe the provari has a cut out at low voltage, but obviously overcharging is still an issue.


Oh btw, the batteries should not get more than slightly warm when charging.

[Neozero]

steve321, on 08 November 2011 - 10:09 PM, said:

would this happen with a provari?

It shouldn't Steve. Fair bit of built-in techie protection stuff going on in them and worse-case, their vented.

[paulharman]

TheStalker - no I dont believe most of them do. Still even with vent holes, wouldnt fancy being near the stuff coming out

[BardicDruid]

All a meter will do is give you the voltage available on the battery, it gives no indication of what the capacity is. A decent battery tester will give you that info, when batteries are at different capacities the one with the most capacity charge will have the most drain which will cause it to heat up. Many times I've tested batteries on a meter and both would have the same voltage but the capacities would be different, I've also had batteries that would read a full charge but only have 40 to 60% capacity.

I use this tester at home: http://www.batteryju.../zts-mbt-1.html , I've checked it with the professional model I use for work and it is just as accurate. By matching your batteries by capacity you will equalize the drain on the batteries and prevent over heating of just one cell, about the only thing I use a meter for with batteries is to check the charger to see if it's charging properly.

I've worked in the electronics field for 20+ years, I regularly replace rechargeable batteries in different types of equipment and seen how the progression of batteries has come. The Li-Ion is the safest battery I work with and the least hassle to maintain, but as with any type of device that holds an electrical charge care must be taken to prevent accidents.

[tommk3cab]

BardicDruid, on 08 November 2011 - 10:41 PM, said:

All a meter will do is give you the voltage available on the battery, it gives no indication of what the capacity is. A decent battery tester will give you that info, when batteries are at different capacities the one with the most capacity charge will have the most drain which will cause it to heat up. Many times I've tested batteries on a meter and both would have the same voltage but the capacities would be different, I've also had batteries that would read a full charge but only have 40 to 60% capacity.

I use this tester at home: http://www.batteryju.../zts-mbt-1.html , I've checked it with the professional model I use for work and it is just as accurate. By matching your batteries by capacity you will equalize the drain on the batteries and prevent over heating of just one cell, about the only thing I use a meter for with batteries is to check the charger to see if it's charging properly.

X2, Have to deal with this all the time in cars with multiple battery setups... the results tend not to be so damaging to your heath... can be pretty nasty on the wallet though

[paulharman]

So it seems most people are aware of the correct usage of li-ion, but 3 people weren't so at least thats 3 more people that are now aware

[Trog]

okay scary stuff but so is being struck by lightening..

first thing.. the most common use for 18650 batteries is Laptops.. they have been known to spontaneously catch fire.. are you aware of that danger.. they also get left on charge over night.. millions are in daily use though..

cell phones.. they use lithium cells they have been know to explode and blow your ear off.. and they are left on charge over night.. are you aware of that danger..

lithium cells could be banned from airplanes.. they could be banned from public sale.. my advice is dont use them at all... chuck all your lithium powered thingies (power tools now) in the bin in fact dont use that nasty elastic trickery stuff at all.. it aint safe..

"idiots" should not be allowed near 18650 li-ion batteries anyway.. it may be possible to educate those who wish to be educated.. but "idiots " are clever.. if its possible to f-ck something up they will do it..

charge outside in a flame proof box.. but above all never put one with charge in it near your face..

trog

ps.. the guy who blew that torch up ether rigged it for effect or comes well and truly in my "idiot" bracket.. he should stick to duracell powered torches..

Edited by Trog, 08 November 2011 - 11:26 PM.

[Digisatman]

Trog easy up mate you might blow you cardiac pacemaker which runs on Li on

[paulharman]

Indeed laptop batteries do contain multiple 18650's.... but there is also a lot of clever electronics in that battery. I'm by no means saying don't use them! Hell, I use them daily in my flashlights and ecig. I'm just saying people should be aware of the potential risks if they are not treated correctly.

This is the chap with the flashlight above. I don't think he would go to the effort of applying bandages in a setup but hey I might be wrong.



Most of it is common sense, but with the amount of rubbish coming out of china, leaving a laptop plugged in overnight and a cheap 18650 charger overnight are very different.

Edited by paulharman, 08 November 2011 - 11:39 PM.

[Neozero]

I cycle to work with power assistance from 36v-worth of L-ion in a pannier behind me, two 18650 Cree torches on the handlebars and an iPhone. Then I spend all day in close proximity to Difibs armed with 30.2v-worth of L-ion and eat lunch in a messroom next to the room where rows of the same L-ions are in various stages of chargedness 24/7.....and at night, all those Difibs power themselves up and go into auto self diagnostic mode at 3am
.........,..Holy CRAPOLA!!!! I'm going to die!!!!!
In fact, I don't know how I've survived this long??
Don't PANIC mr Mannering! (where's the headless chicken smily when you need one? )

[paulharman]

Right yeah because the electronics in a dfib is the same as a £5 chinese charger isn't it.

[Digisatman]

paulharman, on 08 November 2011 - 11:52 PM, said:

Right yeah because the electronics in a dfib is the same as a £5 chinese charger isn't it.

Paul chill man remember your promise

[paulharman]

I see Ecigwizard have a link to a battery faq which has a link to lithium ion safety concerns.

Digisatman, on 09 November 2011 - 12:04 AM, said:

paulharman, on 08 November 2011 - 11:52 PM, said:

Right yeah because the electronics in a dfib is the same as a £5 chinese charger isn't it.

Paul chill man remember your promise

I know mate, but I try to put up a helpful post and get people belittling me. Even the link above shows its not just me who want people to be aware

Edited by paulharman, 09 November 2011 - 12:09 AM.