Battery Safety/Usage Questions

[gerlin]

Newbie here, I have been reading through the threads and just want to make sure I have a handle on battery safety. I know this has been discussed many times and i believe I have read most of the available information, though I feel this is so important I just want to make sure I understand correctly. I also want to print out the safety list (when updated with feedback) and put it above my charging station.

So for those that have the patience, please let me know if I have the important information (I also have a few questions mixed in). I will assume that many do not follow all of the recommendations, though for this list I would like to error on the side of safety.

To make sure I am clear I am not stating that the below list is best practice, I am asking for feedback on the list. DO NOT use this as your guideline, it may be very inaccurate!!


AA Enloops
Charge rate should be 1C or less.
Should NiMH batteries should be "formed" for best performance?
Nothing to really worry about using single or multi-cell lights.
No need to remove cells from flashlights when not being used (either single or multi-cell lights).
Is there a need to make sure charger (such as MH-C9000) is in a fire resistant location?


CR123A
Make sure to use quality protected cells.
Store cells so they cannot short out (or contact other cell's terminals)
Is there a need to store cells in fireproof location?

Lights using single cell CR123A:
Any concerns about putting light in pocket?
Should cell be removed from flashlights when not being used? (Not talking long term, maybe up to a week between uses)

Lights using multiple CR123A:
Confirm that cells are in same state of charge (balanced). Method: check voltage while under load (using ZTS pulse load tester and multimeter). What is acceptable variance?
Does balancing check need to be done when first inserting new batteries? In other words, will the cells in a light discharge at the same rate, or if there is a defective cell, could it discharge at a different rate and cause an imbalance after use?
Any concerns about putting light in pocket?
Should cells be removed from flashlights when not being used? (Not talking long term, maybe up to a week between uses)


LiIo 18650 (and other 3.6v LiIo cells)
Make sure to use quality protected cells (AW).
Charge rate should be 1C or less. Then top off at ~50-300mA CV.
Do not charge if below 2.5v? (I have seen different numbers on this)
Do not charge if above 4.1v? (I have seen different advice on this)
Charging should stop at 4.2v.
Do not discharge below 3.5v.
Retire cells if they are below 2.5v? (I have seen different numbers on this ranging from 1.5v to 3.0v)
Retire cells if they are over 4.3? (due to charger malfunction).
Retire cells if 1 hour after charging (with no load) voltage has dropped by more than .2 volts. (below 4.0v after full charge)
Retire cells if they get hot during charging.
Stop charging if cells get hot 35c (warm is ok).
Remove cells from charger when charging is complete.
Use quality charger, either Pila IBC or a hobby charger designed for LiIo cells.
It is best not to let the cells get to the low end of their storage capacity (more for longevity than safety?)
Store cells so they cannot short out (or contact other cell's terminals)
Long term store cells at 3.6v.
Batteries should be in fireproof location during charging and monitored regularly
Is there a need to store cells in fireproof location?

Lights using single LiIo cell:
Should cell be removed from flashlights when not being used? (Not talking long term, maybe up to a week between uses)
Any concerns about putting light in pocket?

Lights using multiple LiIo cells:
Confirm that cells are in same state of charge (balanced). Method check voltage of each cell (no load required). What is acceptable variance?
Should cells be removed from flashlights when not being used? (Not talking long term, maybe up to a week between uses)
Any concerns about putting light in pocket?


RCR123A
Same behavior as 18650, other than voltages?


Anything else important I am missing? (As far as regular practice, I know cells should not be thrown in a campfire, etc).

Thanks in advance for taking the time to make sure I am on track and answering any of my questions.

 

[old4570]

1st / Primaries or CR123A are not available with protection circuit , only rechargeable 16340 [ RCR123A ] are so equipped .

You can safely discharge to 3v if you wish [ 16340 - 18650 ] [ many drivers-flashlights have built in protection @ 3v ] but as such may not work with primary cells , 1 x CR123A

Many stop @ 3.5v as this is where battery performance drops of sharply ..
Also helps the cell structure remain intact if the Charge discharge levels are smaller [ more battery life ] , but Im not so sure that its so important , depending on just how much use the battery gets ..

If it were charged every week , that would = 50 something times a year , and if the battery is good for 500 to 1000 recharges , its going to take 10 years just to get to 500 at such a rate ...

Unless your going through a battery every day or more [ security work etc ] then it might pay to be frugal ... and careful use may pay off with longer life .

 

[gerlin]

Thanks for you response and information on discharge voltage vs longevity of the cell.

I guess I am a little confused on the protection for CR123A batteries. I have read something like this a couple places in the forum (and vendor sites):

CR123 batteries have a PTC device, which limits the short circuit current to 5 - 8 AMps, and then disconnect the battery. It is a device intended to avoid the explosion of the battery in case of prolonged short circuit.

Every Titanium CR123A battery incorporates PTC protection (a type of thermal fuse) and the PTC threshold is set at 5AMPS. The protected Titanium CR123A batteries prevent excessive discharge that can damage lithium cells and may lead to catastrophic incidents.

I am assuming that this type of "protection" is less sophisticated than that used on a LiIo from a quality cell like AW and that is why it is considered unprotected?

Again,thank for the information.

 

[old4570]

The protection is inbuilt , into the battery , rather than a electronic circuit .
Bit like a fuse I guess , current goes to high and the inbuilt fuse melts permanently disabling the battery .

Some 18650 batteries have such a feature as well ...

 

[VidPro]

AA Enloops
Charge rate should be 1C or less.

oh cripes, it is never so simple, why cant it be simple.
the charge rate should be ~.3C or more , IF the charger is trying to detect a "v-drop" for its termination.
if it is not a V-drop termination style charger, even the .3C rate might be incorrect for that charging alogrythm, there are many cheap chargers that just do not work that way, and will still work "fine" for charging eneloops.
it just soo totally depends on the charger type and style, some just slow down and finish by voltage , some MUST have a v-drop, some work with MAX voltage too, and some time out about when a emptry one would be charged, and some use various combos of all of that.
how the cell acts for a v-drop also depends on how long it has sat on the shelf and all.
if your going to PEG one setting, then do it for your charger that your using, that would be best.


Should NiMH batteries should be "formed" for best performance?

Does not make a lot of differance, plus there are many ways to use the word "form" just to complicate matters.

"Forming" is best done on any ni-?? that has not been used in a long time, and a full complete end to end cycle is usefull to get them going well.
that is its bigest assett, is it more fully discharges, and more completly charges all the chemicals in the cell item, it "Cycles" the whole thing.

"formed" is also a term used to define a rate of charge , that the chemicals get slapped into place, faster or slower depending on the batteries uses.
If you got time, Form them, if they are LSD dont waste a lot of time forming them because the same properties that make them LSD make them so they dont require cycling so much to "re-align the chemicals using power"

I would be more likely to "form" using a fuller discharge and slow charge method, if i felt that the battery was not up to par, THEN attempting to get a more fuller cycle on it, finishing still with a potent charge to "form" it for fast discharge.

Nothing to really worry about using single or multi-cell lights.

Well , again, if only it were that simple. sure it cant explode and burst into flames sending people screaming and running for cover
In single lights you can do about anything, just prefer that you charge it after it has become drained fully within a reasonable time of it being drained.

in muli-cell lights Quickly stated, just do NOT ever drain them down too far, if the light goes dim unless it is some emergency replace the batts, or recharge them. Reverse charge can damage cells badly. For further info, learn what causes "reverse charge" in multi-cell lights with no cut-off.

No need to remove (ni-??) cells from flashlights when not being used (either single or multi-cell lights).

Yes , unless the light has parasite power drains , unlike a alkaline it is far less likely to cause any corrosion or spew or expand and damage or ruin a light even after long times. but still if things were wet inside , or something odd it doesnt hurt to check and see what is happening.

Is there a need to make sure charger (such as MH-C9000) is in a fire resistant location?

Always, is there anything that doesnt blow up (rarely) nowdays really we have PSUs inside of computers that yearly a significant quantity of people report Exploding capacitors flames shooting out the back of their computers. the 9000 is a good safer form of charge alogrythm stuff, but power is power, and stuff can still happen.

 

[VidPro]

CR123A Lithium Primary cells.
Is there a need to store cells in fireproof location?

Yes, and oddly enough there are more reported issues with them when Discharged, soooo the most care might be needed in the most unreasonable times , when there is least power in them :duh2: (probably has to do with the reverse charge thing again)

Lights using single cell CR123A:
Any concerns about putting light in pocket?

Me i dont worry about it, but the one thing that would be VERY valuable to know , is the majority of the time on the rare chance of a Bad occurance, you get a warning.
your pocket starts heating up (dang switch) a Rumble, a Pop.
if your going to store them in your pocket , without being paraniod or making anyone paranoid, OFTEN you can know that something is going wrong.
Just pull it out, Turn it off if it was ONLY because it was on.
if it is WAY hot, rumbles, shakes, pops, vibrates, or switch boots are bulging. just drop it and move away till it either does something or not.
remember in the flashlight Case then insulated by the fabic of a pocket a light left on can reach thermal condition all on its own, so just your pocket going all campfire on you is a reason to addresss the situation, and without running people off the road or unhooking your parachute

Should cell be removed from flashlights when not being used? (Not talking long term, maybe up to a week between uses)

I would not , i am using that cell item because of its long life, and i am knowing its approximate state of charge , not for just a few weeks.
If you had mostly Expended it, then refer to the above, it might be less safe.

Lights using multiple CR123A:
What is acceptable variance?

on a ZTS 0 Ok well we will give you a 10% because it cant read more than that. on a DMM .03-4 , i think you just get a feel for it, they either are working in much similarity or it shows up big. it is only seeing that counts, when you do that, you see everything fast.

Does balancing check need to be done when first inserting new batteries? In other words, will the cells in a light discharge at the same rate, or if there is a defective cell, could it discharge at a different rate and cause an imbalance after use?

For some "not totally understood" reason series cells do not stay the same, the heat is different in most light items. but even in light items where the heat was Not different, it has still been reported that one battery Location will go down before the other. it is close but not perfect.

When one cell was wrong, then it will show up quick (again) because your looking, and that is the the KEY, that you checked.
a bad , poor, or defective, or just a cell you didnt check well enough would certannly go down before the good one, which can bring about the evil "reverse charge" when in series.

Any concerns about putting (SERIES) light in pocket?

IF the light got offset via the batteries , or one cell gave up the ghost, or i thought there was ANY chance of reverse charge i am not putting it by my gonads. so if it has Died. if i had to put in some unknown batteries. if someone hands me some cheap junk. No Way not in series.
if i checked it and all is well it is bright cheery i got good cells in it, no problem.


Should cells be removed from (SERIES) flashlights when not being used? (Not talking long term, maybe up to a week between uses)

Same applies, if the light has any parasite draw , or drains batteries , got wet (which can conduct power) has bad or dead cells in it, nope. otherwise that is WHY i was using the lithium cell items. Parasite draws and bad batteries left in series would be of far more "consequence" than in singles. if everyting is ok, because your smart enough to check, then storing them in the light between uses is not a problem.

 

[gerlin]

VidPro, those were very helpful and informative posts.

Thank you for taking the time to share this with me.

Do CR123A cells need to be under load to check the voltage properly (for balancing), or is a load not required?

 

[VidPro]

yes prefer to test any battery under a load, it tells so much more about it.
in the case of lithium if it was just used it will be good too, even without a load it should show you enough.

in the li-ion, which i might eventally take a crack at answering those Qs too, a load is not as nessisary as the resting voltage tells a lot.

 

[Battery Guy]

When I started writing my responses below, nobody had replied to this thread. Now, three days later, there are several good replies, so I am afraid some of this information may be redundant.

AA Enloops
Charge rate should be 1C or less.

If you are using a -dV charger, then the rule of thumb is to charge between C/2 and C (1-2 A for the Eneloop) for a NiMH cell. If the charge is timed, then charge at a C/10 rate for 14-16 hours.

Should NiMH batteries should be "formed" for best performance?

Technically, the formation cycle is performed by the manufacturer. When you get the cells, they have already been formed and have gone through probably 3 charge/discharge cycles.

However, you might be asking about a break-in cycle. Eneloops really do not need a break-in cycle when they are fresh out of the package. The only time I might recommend a break-in cycle on an Eneloop is if it has been sitting completely discharged for a long period of time (i.e. several months).

Nothing to really worry about using single or multi-cell lights.
No need to remove cells from flashlights when not being used (either single or multi-cell lights).

Well, you need to worry about mismatching cells. You should always use cells of similar age, use history, capacity and impedance. This is good practice for any multi-cell application.

Is there a need to make sure charger (such as MH-C9000) is in a fire resistant location?

As with any electronic device that is charged off the mains (laptop, cell phone, etc...) it is wise to put it on a surface that is non-flammable and well ventilated.

CR123
Make sure to use quality protected cells.

CR123 cells are non-rechargeable and do not have electronic protection, although most have vents and PTC (positive thermal coefficient) devices that help to prevent damage caused by external short circuits.

Store cells so they cannot short out (or contact other cell's terminals)
Is there a need to store cells in fireproof location?

Obviously store cells so that they cannot short out. Unless you store your cells in a metal box along with a handful of steel wool and bare wire scraps, I do not see the need to store cells in a fireproof location.

Lights using single cell CR123A:
Any concerns about putting light in pocket?

Personally, I will not put a CR123 cell in my pocket. I have seen too many safety issues with them. However, I have no problem with an Energizer L91 or Eneloop powered light in my pocket.

Should cell be removed from flashlights when not being used? (Not talking long term, maybe up to a week between uses)

I guess that there are some lights that have a leakage current when shut off, but most lights do not. Also, a lot of people accidentally leave the light on, then end up overdischarging the battery. So there are a few good reasons for being in the habit of removing the batteries. However, from my perspective, as long as you are aware of the potential problems, I think it is a waste of time to remove the batteries when not in use.

Lights using multiple CR123A:
Confirm that cells are in same state of charge (balanced). Method: check voltage while under load (using ZTS pulse load tester and multimeter).

Personally, I prefer to keep it simple, and only use new cells in lights that require multiple CR123 cells, or even AA lithium cells for that matter.

What is acceptable variance?

There is no rule for an acceptable variance. It is precisely this uncertainty that has convinced me to just be safe and always use new cells in multi-cell lights that use lithiums.

Does balancing check need to be done when first inserting new batteries? In other words, will the cells in a light discharge at the same rate, or if there is a defective cell, could it discharge at a different rate and cause an imbalance after use?

Assuming the cells are in series, they will draw exactly the same amount of current, and therefore will not go out of balance during use.

Any concerns about putting light in pocket?

I will not put a light that uses CR123 cells in my pocket, ever. I know that I am being overly cautious, but the sheer number of people who have posted on CR123 thermal failures has really convinced me that it is not a good idea.

Should cells be removed from flashlights when not being used? (Not talking long term, maybe up to a week between uses)

Same answer as above. There should really be no reason to remove the cells unless you are shipping the light, or if your flashlight is known to have a leakage current that could drain the cells.

LiIo 18650 (and other 3.6v LiIo cells)
Make sure to use quality protected cells (AW).

There has been a lot of discussion on this. One very good reason to buy AW cells is that they appear to be sourced from very good quality manufacturers. I believe that someone recently found that the 18650s are Panasonic. With respect to protection, I am on the fence with that. I do not like the way the protection circuitry is added, especially the nickel strip that goes from the positive terminal across the crimp and down the side of the cell. I fear that this possess a risk of an external short circuit. That being said, I have not heard of a problem associated with this.

I think that as long as you treat protected cells as if they are unprotected, you should be fine. However, I would not rely upon the protection circuitry. Also, be aware that no amount of external protection is going to help you if the cell has an internal failure.

Charge rate should be 1C or less. Then top off at ~50-300mA CV.

That is a good rule of thumb to follow.

Do not charge if below 2.5v? (I have seen different numbers on this)

You see different numbers because there is no hard rule for the cut-off voltage. The voltage below which degradation begins in the cell that can make it unsafe is different for every cell design, and actually changes over the life of the cell.

That being said, I think that if you stick to your rule of not charging a cell that has an OCV of <2.5 V, you will be pretty safe.

Do not charge if above 4.1v? (I have seen different advice on this)[/COLOR]

I don't see any reason why a cell at 4.1 V cannot be topped-off to 4.2 V.

Charging should stop at 4.2v.

Unless otherwise specified by the manufacturer, most lithium-ion cells are at top of charge at 4.2 V. Cells with the iron phosphate cathode are typically charged to ~3.8 V. Some of the more exotic cathode materials are designed to be charged to 4.3 V. Check your manufacturer's specs if in doubt.

Do not discharge below 3.5v.

A cell with an OCV of 3.5 V has essentially no capacity left (unless you are talking about an iron phosphate cathode). However, it is unlikely that you have the ability to check the voltage under load while you are using your flashlight. This is where it gets tricky, and where having some protection on the cell can be advantageous. In general, you probably do not want to discharge the cell under load to <2.5 V, but since you don't know the voltage of the cell under load, your best course of action is to never fully discharge the battery pack in the flashlight.

Sorry, there really isn't a better answer for you on this one, at least that I know of.

Retire cells if they are below 2.5v? (I have seen different numbers on this ranging from 1.5v to 3.0v)

See above. If you have a cell that has an OCV of <2.5 V, it is probably safest to just retire it.

Retire cells if they are over 4.3? (due to charger malfunction).

This is a good idea. There is a high probability that the cell has been permanently damaged if it is overcharged, so best to just get rid of it.

Retire cells if 1 hour after charging (with no load) voltage has dropped by more than .2 volts. (below 4.0v after full charge)

The amount of voltage drop after charge is going to depend on the charging rate and the cut-off current in the CV stage. If you cut-off at a C/10 current (say around 250 mA), then you should expect the cell voltage to drop no more than 0.05 V. So, in my experience, if it drops below 4.15 V in the first hour, there is probably something wrong.

Retire cells if they get hot during charging.

Definitely

Stop charging if cells get hot 35c (warm is ok).

Well, I guess you need to define "hot". Most lithium-ion cells are rated to operate up to 50 degC. But there is really no reason that a cell being charged at room temperature should get above 35 degC.

Remove cells from charger when charging is complete.

Probably not necessary, but a good habit.

It is best not to let the cells get to the low end of their storage capacity (more for longevity than safety?)

Probably both safety and longevity.

Store cells so they cannot short out (or contact other cell's terminals)

Obviously

Long term store cells at 3.6v.

anywhere between 3.6 V and 3.8 V is fine

Batteries should be in fireproof location during charging and monitored regularly

Yes

Is there a need to store cells in fireproof location?

I do not believe that this is necessary, so long as you store the cells in a manner that eliminates the risk of shorting.

Lights using single LiIo cell:
Should cell be removed from flashlights when not being used? (Not talking long term, maybe up to a week between uses)

Same as the answers for other batteries. Not necessary to remove unless your light has a leakage current, or you want to eliminate the potential that the light could be turned on accidentally.

Any concerns about putting light in pocket?

For pocket use, I would only use NiMH or lithium AA primary cells made by Energizer.

Lights using multiple LiIo cells:
Confirm that cells are in same state of charge (balanced). Method check voltage of each cell (no load required). What is acceptable variance?

Use cells purchased at the same time, charge them the same and put them in the light fully charged.

Should cells be removed from flashlights when not being used? (Not talking long term, maybe up to a week between uses)
Any concerns about putting light in pocket?

Same answers as single cells.

RCR123A
Same behavior as 18650, other than voltages?

I don't use anything other than 18650 and 26650 lithium-ion cells. Most of the "odd" cylindrical cell sizes are made by questionable cell manufacturers because the volume of cells produced are not high enough for the large, high quality manufacturers to be interested.

That being said, I believe that Sanyo makes a fair number of odd cylindrical sizes. If you can get an RCR123 cell from a well known, reputable manufacturer like Sanyo, then go ahead and use it and treat it the same as any other lithium ion cell.

Anything else important I am missing?[/COLOR] (As far as regular practice, I know cells should not be thrown in a campfire, etc).

I think you covered most of it.

Cheers,
BG

 

[Mr Happy]

Technically, the formation cycle is performed by the manufacturer. When you get the cells, they have already been formed and have gone through probably 3 charge/discharge cycles.

There was some discussion here in the past regarding some very cheap NiMH cells that can often be found from non-mainstream brands. It turned out that when first purchased these cells would test far below their label capacity and would need many break-in cycles to get the capacity up to spec. We inferred from those results that the manufacturer was keeping the price down by skipping the forming process in the factory and leaving that to the purchaser. So unless you have a lot of time and patience it seems that it is worth paying that bit extra and getting brand name cells that perform to spec when you receive them.

 

[Battery Guy]

There was some discussion here in the past regarding some very cheap NiMH cells that can often be found from non-mainstream brands. It turned out that when first purchased these cells would test far below their label capacity and would need many break-in cycles to get the capacity up to spec. We inferred from those results that the manufacturer was keeping the price down by skipping the forming process in the factory and leaving that to the purchaser. So unless you have a lot of time and patience it seems that it is worth paying that bit extra and getting brand name cells that perform to spec when you receive them.

All rechargeable batteries are assembled in the "discharged" state by the manufacturer, and they should all go through a "formation" cycle(s) at the manufacturer. The formation cycle is critical, and is almost always performed under very well controlled temperature and charge current conditions in order to get the correct properties in both electrodes. Any battery manufacturer who sells an unformed rechargeable battery is seriously negligent, and should be avoided at all costs.

All battery manufacturers that I have visited use the data collected during the formation cycle as critical input into their quality control process. Any manufacturer who does not do this has essentially zero quality control.

Mr. Happy: I am not questioning that some manufacturers have sold unformed batteries. I am simply reinforcing your statement that when these manufacturers are identified, people should run away!

Cheers,
BG