Blame the Battery ....

old4570

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Well as the heading suggests , seems a lot of folks blame the battery when something goes wrong ...

Lets get one thing straight right away - Li-ion's have the potential to be DANGEROUS ! This is a fact no one should underestimate ...

A lack of knowledge or due care can result in potential disaster ...

Buying cheap cells has its risks , quality control , discharge capability , and even internal capacity ..

These things may not be an issue in single cell lights ... In fact all you may suffer is diminished output and shorter run time , possibly even longer run time [ BRC3000 ] .

And in no way does it mean that buying expensive cells is safe , lets get that straight as well , what you hopefully are buying is better quality control and more closely matched cells in terms of performance ...

Single cells lights will always be safer than multi cell lights , its just a Li-ion fact ..

The more cells you run , the greater the risk , especially in series ..
Most of the incidents involve multi battery set ups , is from what I would consider a lack of due care on the users part ..

So lets for a moment look at what U the multi battery user should be looking for ...

To start with , OFF THE CHARGER !

Dont , ever , pull the batteries off the charger , measure voltage and then throw them in a light .. It takes 30 minutes to 60 minutes for the battery to stabilize .. Fresh of the charger it might give a reading of 4.2v after 30 minutes it could be 4.19v or 4.18v and after on hour it could be down to 4.15v .. It depends on the quality of the individual cell .. Fresh readings can give you a false battery state , you need to establish the quality of each cell you use ... Are you doing this ?

Next , discharge capability .. The higher performance the light [ the more current it draws ] the more important it becomes to match the discharge of the cells . Are you matching the discharge capability of your cells ?

Cell capacity , again can vary some what , more possibly with cheap cells . Imagine if you will one cell has 2400mA capacity while the other may go 2550mA ,

What can happen : When you dont match the cells or use due care ...

Of the charger .. You think there fully charged , but one cell sags to 4.15v and the other does not .. Its not a huge variable , and under low current applications may be nothing worth worrying about ..

Next Discharge capability , one battery [ lets say the one that goes 4.15v after a bit of sag after charging ] has less discharge capability , whilst the other has very good discharge capability ...
Lets say you light draws 1.5A @ 8.4v for 12.6W [ SSC P7 for arguments sake ] What we may find is that the not so good cell gets stressed much worse than the good cell , and over a short time degrades even more ..
To the point that the two cells are dangerously out of balance . And lets not forget the real capacity of each cell , if its out , it will contribute to an out of balance state ...

Seems a lot of incident occur with new lights , and the operators dont test anything , and assume too much ..

Mixing used with new cells also seems to be an issue ..
How many actually own a multimeter ?
Im sorry , blaming the battery ? Sure you need a scape goat , I can understand that , its the way of the modern world , no one seems to want to take responsibility for there own actions ...

You should

If you use Li-ion in a multi battery set up , BUY A MULTI METER , if you dont , then dont dare post here how the batteries failed you and vented ..

Let the batteries sit for a least one hour after charging , and then test them for voltage state ...

If you run a really high performance light , go to the trouble of matching the batteries for current delivery ...

Before charging the batteries [ after use ] test voltage state , take note of the position of the battery , you want them to be as close as possible after use .. You dont want to see one battery @ 3v and the other at 3.5v ..
Are you testing after use ?

For single battery users , the only real issue is , shorts , over discharge , and making sure you have your charging method sorted out , monitor the charger if its does not terminate on completion ...

If you fail to do your part , the batteries may fail you , dramatically and possibly dangerously ...

If you dont own a Multi meter , you Blind to whats going on , blind people dont see anything ..

Dont go to the trouble of matching cells , again , you have no clue to whats going on ..

Dont test , and test more , how do you know whats happening ?

Seems a lot of folks are prepared to pull the pin on a hand grenade and put it in there pants ..

:oops: Yeah , must be the battery !

When I hear this stuff , it makes me think of the idiots cleaning there guns and shooting a family member , because they didnt know the gun was loaded .

Li-ion has the potential to be DANGEROUS !
And people have the capacity to be even more dangerous ..

So the only question remaining to be answered , are you a safe Li-ion user , or a Dangerous one ...

I havent covered everything , but hopefully enough !

Be safe everyone ...
 
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don.gwapo

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Thanks. Learned something from you. So i'm a little bit on the safe side coz all my lights are single cell.
 

LEDAdd1ct

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What you say is true, and though not cause for alarm, is cause for thought, especially folks not familiar with multi li-ion setups. I am having a light made with 2x26650, in series. This has the potential to be dangerous, since they are unprotected and, as noted, in series. However, I do own a multimeter, I will own a good charger, and I will test the cells to see how closely matched they are.

Like most things in life, this is a balance, with the responsibility on the user split between the physical and the mental:

Physical

1) Did you buy quality cells?
2) Did you buy a quality charger that terminates properly?
3) Do you own a quality multimeter?

Mental

1) Are you aware of the proper care and feeding of said cells?
2) Do you know how to operate your multimeter?
3) Are you familiar with the terms commonly used with these cells?
4) Do you know who some of the electrical "experts" on CPF are to seek assistance from, or, do you have someone in your family/house/peer group knowledgeable in same?
5) Are you prepared to measure your cells, especially in high drain, multi-cell configurations, for close voltages?
6) Are you aware of the current drain of the particular light you intend to use said cells in, and, the equations necessary to calculate, for a given set of cells with a given capacity, what an appropriate amount of runtime is?

I believe that to paint the [potentially] dire consequences as entirely the fault of the goods or entirely the fault of the user is constructing a false dilemma, when, in fact, the responsibility is shared between the two. Unsafe materials and/or oversight in materials handling are both dangerous.

That said, this is a fine hobby, and there are many beautiful lights with li-ion cells and li-ion cells in series. However, each user must be prepared to undertake the responsibility in obtaining the proper goods and learning/maintaining the proper behaviors to use them safely. Good behaviors over time become good habits, and it is a measure of both the material [goods] and immaterial [behaviors] that is required for safe operation in the li-ion realm.

Most important of all, there is nothing shameful in asking for help. Every member of this board had a "1" in the top right corner of their posts at one point in time. If you are new to these cells, this chemistry, or this hobby, read the many well-written articles already posted by members, search, and if you are at all uncertain, ask!

:thumbsup:
 
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old4570

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Was I trying to scare people , a little !

At the very least , to respect the Li-ion's power .

To possibly impress upon them the higher standards needed when taking greater risks . And I think multi battery use has proven itself , some what risky , and in need of some care .

:wave:

Anyone can drive a car at 10MPH , it takes great skill to drive one at 200MPH
 

TooManyGizmos

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~

YEP ....... that pretty much sums it up .



( Learn how to pack that parachute properly ..... BEFORE you take the LEAP !)

~
 

LuxLuthor

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Old4570, that was an excellent post, and demonstrated most of the key points. Only thing I would add is to say "Generally, buying cheap cells has higher risks..."

Again, thanks very much for this post! :thumbsup:
 

Battery Guy

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Which of these risks remain when using Lithium Manganese chemistry cells?

--flatline

Lithium Manganese Oxide (aka LMO, spinel, manganese) cannot be overcharged. Unlike all other lithium-ion cathodes (except LiFePO4), the LMO cathode is completely exhausted of lithium ions at the top of charge. Charging to higher voltages may damage the electrolyte and hurt performance, but it will not result in an unstable, unsafe cell.

In comparison, you have only removed about half of the lithium ions from an LiCoO2 cathode at 4.2V. If you charge to higher voltages, you will continue to remove lithium and put charge into the cell. So overcharging an LCO cell to higher voltages puts more stored energy (more Watt-hours) into it, and it also makes the cell more thermally unstable. Picture old, sweaty TNT and you will have the right idea.

This is one of the big safety advantages of both LMO and LiFePO4 lithium-ion cells.

However, what everyone must remember about ALL lithium-ion batteries is that they use a combustible electrolyte. The combustion energy of the electrolyte is actually equivalent to the stored electrical energy of the battery. Basically, all bets are off if you ignite that electrolyte, no matter what type of lithium-ion cell you have.

Cheers,
Battery Guy
 

Battery Guy

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I don't know much about most things, but when it comes to batteries I feel that I am relatively up-to-speed with what is going on.

When it comes to lithium-ion, I would say that I am at the top of my game. I have been working professionally in this field for over a decade, in research, manufacturing, safety and application development.

So, when I say that I don't feel ready to use lithium-ion cells in my own personal flashlight modifications, I hope that some of you take this to heart.

When I do start using lithium-ions in my flashlight mods (and that may be relatively soon), I will only use cells from known, top tier cell manufacturers. Since cells from these manufacturers tend to be hard to come by, I will likely harvest cells from a power tool or laptop packs. I will NOT use protected cells. I will either charge the cells individually outside of the flashlight or build a custom pack with balancing leads and use a balancing charger.

For what its worth.

Cheers,
Battery Guy
 

ASheep

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Congrats on a well written post old4570.

People should not be scared of lithium-ion cells, but have a healthy respect for them, much the same as one would have a healthy respect for venomous snakes. If you treat them properly, they PROBABLY won't harm you.

This is a great resource for newer members, or people just starting out with lithium-ions. Before I began using Li-ions, I read and reread every warning, MSDS, care and handling sheet, explosion story and general battery rant I could find. A sound knowledge of chemistry and materials science helped too.

I think in addition to the "threads of interest" in the battery sub-forum, there should be a collection of safety threads. This would be a valuable resource for any user of li-ion cells.

Edit: While I was writing this, battery guy made his post above, I must say that the more you know about li-ion cells, the more reluctant you would be to put them inside a pressure vessel. As for unprotected li-ions, I find too many people think that because their cells are "protected" they won't fail. They run the cells down until the protection kicks in, slap it in the charger, dump it back in the light hot off the charger. This is plain unsafe, and bad practise. These suckers aren't your garden variety Ni-MH cells, where the worst that can normally happen is a bit of "sticky goop" (electrolyte) coming out.

A piece of advice for all people using li-ions in lights: Measure the overall current draw from the battery on each mode you use. KNOW how long your light can theoretically last on your cell's capacity, and then take 10-20% off that, for a safety margin.
I'd rather carry a spare 18650 battery or two individually cling-wrapped in a keep2go tube or similar, than risk killing my battery from overdischarge, or worse, a vent situation from mis-handling. If in doubt, swap out the battery. Always take the most cautious path, not the easiest.
 
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jacknife

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I am only using AW protected 18650's , and panasonic cr123's, I have a ZTS-MBT1 tester. I have tested all lights with the CR123's. and on the ZTS tester they are all running at the same percentage, I have not yet tested the 18650's,that are in lights now. If I have one light, that is operating off one 18650, At what percentage on the ZTS tester, 80% , 60% ,40%, 20%, should I recharge that 18650? If I am running 2 -18650's in another light, should these 18650,s-- AW protected,,Be always running at the same percentage ??? like is one at 80% and one at 60% bad? I am guessing yes here. -And may I ask at what percentage would you throw away The CR123 batteries?----- And how often do you guys check the batteries you are running in your lights? I know it sounds like I am asking a lot But I am trying to learn MORE. What is the difference between the ZBT tester and the Multi Meter? do I need that too?
 

ASheep

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Jacknife, I recommend you get a digital multimeter to test voltages as well as your ZTS tester. The Multimeter will allow you to match the cell voltages closely, as having two 18650 cells in series with different voltages could be catastrophic. Running Li-ion cells, or even regular lithium CR123 cells at different states of charge (eg 80% and 60% reading on the ZTS) and different voltage (3.7V and 4.13V) will greatly increase the chance of one of the cells reverse charging, venting, and possibly damaging the light and you.

It is not recommended to drain Li-ion cells below 3.0V for longevity, Below 2.7V will begin to damage the cell.
I advise you read the articles on:
http://www.batteryuniversity.com/index.htm
They are full of great advice, and explanations of the innards of your cells.

Stay safe,
Alex
 

jacknife

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Battery University ,,pretty cool. Which Multi Meter should I get --one from ZBT?? Suggestions??
 

ASheep

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There are many threads on CPF about cheap multimeters:
https://www.candlepowerforums.com/threads/188177
https://www.candlepowerforums.com/threads/283653

From these, in the US it seems Radio Shack, Harbour Freight and Sears seem to have reasonable quality Multimeters.
I have an ancient analogue Voltmeter, and a rather old parameters multimeter, both of which are still very accurate (within 0.01V tested with a known 5.0V source) and some newer budget multimeters from **** Smith Electronics here in Australia. They are probably the same ones you could buy at harbour freight in the US.
 

LuxLuthor

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I am only using AW protected 18650's , and panasonic cr123's, I have a ZTS-MBT1 tester. I have tested all lights with the CR123's. and on the ZTS tester they are all running at the same percentage, I have not yet tested the 18650's,that are in lights now. If I have one light, that is operating off one 18650, At what percentage on the ZTS tester, 80% , 60% ,40%, 20%, should I recharge that 18650? If I am running 2 -18650's in another light, should these 18650,s-- AW protected,,Be always running at the same percentage ??? like is one at 80% and one at 60% bad? I am guessing yes here. -And may I ask at what percentage would you throw away The CR123 batteries?----- And how often do you guys check the batteries you are running in your lights? I know it sounds like I am asking a lot But I am trying to learn MORE. What is the difference between the ZBT tester and the Multi Meter? do I need that too?

Thanks for asking about this. You are exactly the kind of member that we want to reach and help you avoid problems. We all started where you are.

As ASheep answered so well, the digital multimeter (DMM) should be seen as a standard required item if you use Lithium batteries (primary or secondary-rechargeable). I also have and use a ZTS tester, but I use it for Alkaline and NiMH cells.

There is a great guideline here to see where you are with Lithium Ion cells:
4.2 volts 100%
4.1 about 90%
4.0 about 80%
3.9 about 60%
3.8 about 40%
3.7 about 20%
3.6 empty

Most protection circuits prevent charging above 4.25V, and discharging below 2.5V. When a cell is empty, it has a sharp spike downward, so even if it quickly goes to a cell damaging low voltage of 2.5V before the protection PCB breaks the circuit, the cell will rebound back up above 3.1V very quickly if it is healthy, and avoid harming it. One of the best threads on the subject was from one of the truly Great Past Members of CPF, Newbie, here.

If you are using two Li-Ion cells together, I try to make sure they are within 0.05 to 0.10 Volt of each other (i.e. 4.12 & 4.18V are close enough; 4.0V & 4.2V are too imbalanced to use together.)
--------------------------------------
Your other question was seeking guidance on CR123A (primary Surefire type cells) voltages. First, make sure you bought cells from USA manufacturers. Since these are never charged, they are going to start at around 3.25V and only go down.

When they get down to 2.7 to 2.8V range they are nearly empty, some have drained them to 2.5V. There is less concern about draining them if being used in a single cell light. In multi-cell lights mainly look for voltage imbalance between the cells. A pair with 2.8V & 2.91V would concern me less than a pair of 3.1V and 2.99V, because there is more energy in the latter pair.
--------------------------------------
Here is something I find curious and cannot explain.

I have various used Surefire CR123A cells. If I check the voltage with two of them having 05-2015 dates on their side, my Fluke 189 DMM gives a reading of 3.05 Volts. Putting those cells on my ZTS (MBT-1) CR123 + terminal, it reports 10% remaining.

I have two other SF cells with 05-2018 dates, that measure 2.91V, but on the ZTS, they report 40% remaining. Neither pair have been recently used. I suspect it must have to do with the dates, but the resting voltage becomes confusing.
 
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LuxLuthor

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When I do start using lithium-ions in my flashlight mods (and that may be relatively soon), I will only use cells from known, top tier cell manufacturers. Since cells from these manufacturers tend to be hard to come by, I will likely harvest cells from a power tool or laptop packs. I will NOT use protected cells. I will either charge the cells individually outside of the flashlight or build a custom pack with balancing leads and use a balancing charger.

For what its worth.

Cheers,
Battery Guy

BG, first make sure you read that thread by Newbie. You especially will appreciate it. You remind me of him.

Could you share your thoughts/concerns on not using protected cells? There is a reinforced idea (whether right or wrong) of the PCB providing a layer of insurance, but it is hard to test if all of its components are working properly. There are also more known incidents here of primary Lithium cell problems than secondary, which lulls us into perhaps feeling more secure using them than we should.

Thanks.
 

jasonck08

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4.2 volts 100%
4.1 about 90%
4.0 about 80%
3.9 about 60%
3.8 about 40%
3.7 about 20%
3.6 empty


Really depends on the cell itself, these figures are quite off for some cells, such as a 3.6v nominal Samsung 2200mAh cell I tested recently. Here were my capacity results from this cell:

4.20v - 100%
4.08v - 90%
3.96v - 80%
3.84v - 70%
3.74v - 60%
3.66v - 50%
3.61 - 40%
3.55 - 30%
3.51 - 20%
3.47 - 10%
3.31 - 0%

These are resting voltages taken after discharging the cell 10% of its actual capacity and then measuring the resting voltage after 10 minutes.

 

LuxLuthor

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Really depends on the cell itself, these figures are quite off for some cells, such as a 3.6v nominal Samsung 2200mAh cell I tested recently. Here were my capacity results from this cell:

4.20v - 100%
4.08v - 90%
3.96v - 80%
3.84v - 70%
3.74v - 60%
3.66v - 50%
3.61 - 40%
3.55 - 30%
3.51 - 20%
3.47 - 10%
3.31 - 0%

These are resting voltages taken after discharging the cell 10% of its actual capacity and then measuring the resting voltage after 10 minutes.


I agree there is variation among most cell brands, further complicated by variation in models of a particular brand, and then between cell batches of the same brand model, age of cells, and degrees of use/abuse over time, but are nonetheless useful guidelines often posted by knowledgeable members, such as Silverfox.
 
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