Help with CR123 batteries

[TacmedRN]

Forgive my noob understanding of batteries throughout this post…

Edit with specific scenario prompting my inquiry:

I'm given primary cells at work (Surefire brand), so while they are SUPPOSED to be fresh, I'm not witnessing them coming out of the box.

So let's say I have two batteries that are both supposedly fresh, but one actually has about 80% capacity. Is this enough of a difference to cause reverse charging?

End edit.

Long ago I read somewhere that if you pair two cr123 batteries with slightly different voltages, one can try to "charge" the other and cause a short or something, posing a fire risk. I've sworn off multi-cell lithium battery powered lights since then, and I've missed out on some great lights.

I'm trying to understand the validity of this, but I don't know what it's called to do a search.

What are the risks of stacking two cr123 batteries with slightly different voltages? Is the risk of fire really that big? I know enough to not pair an obviously used battery with a new battery, but I don't want to have to worry about pairing a brand new fresh battery with a slightly older fresh battery.

Any help is appreciated!

 

[aznsx]

I'm no batt expert, but I do know that it is 'best practice' to put them in service new together as a pair / set, and use them exclusively as a dedicated pair / set. If I do that, and use quality US-produced cells, I sleep just fine. Odds of a problem using that practice are, I feel, minimal. If I didn't adhere to 'best practice', I'd probably be nervous.

 

[bykfixer]

Good questions. Better safe than sorry. There is some danger but mostly when a significant gap in voltage between two cells.

- Use like expiration dates, which most purchases will have.
- Buy US made since they have built in thermal runaway protection required by law. Battery Station, Streamlight, SureFire, Panasonic and silver Rayovac are US made.
- Keep pairs of batteries married. As in if used in a pair, even briefly keep them stored together.

 

[Monocrom]

Oh! You can forget about a fire. Fire would the nicest thing to happen. More like vent with flame. Basically, an explosion. Hold on, it gets worse. Lithium batteries give off highly toxic fumes when the explode. Breath in just a little, you get respiratory issues. Severe ones.... that don't go away even several years later. That's not speculation. That actually happened to one of our members.

He then returned a decade later to inform us of all the medical bills he incurred. How he ended up selling off a good chunk of his possessions to pay said bills. And, how he still was suffering with respiratory issues. (And likely will be for the rest of his Life.)

Lithiums are no joke! You have to have a complete understanding of them before you use them. Yes, laptops have 18650s in them. Cordless battery-operated power-tools have them inside of the battery packs. That doesn't mean they're safe, all the time. Just means such products exist for consumers to buy and use.

 

[TacmedRN]

Good questions. Better safe than sorry. There is some danger but mostly when a significant gap in voltage between two cells.

- Use like expiration dates, which most purchases will have.
- Buy US made since they have built in thermal runaway protection required by law. Battery Station, Streamlight, SureFire, Panasonic and silver Rayovac are US made.
- Keep pairs of batteries married. As in if used in a pair, even briefly keep them stored together.

Out of curiosity, what happens if an old and new cr123 are paired?

 

[Monocrom]

Out of curiosity, what happens if an old and new cr123 are paired?

Vent with flame.
You're not guaranteed that will happen. But realistically you are putting yourself in needless danger of it happening. Would you give a sleeping lion a little poke in the balls with a sharp stick, then wait to see what happens next? Of course not. Same thing.

 

[thermal guy]

Oh! You can forget about a fire. Fire would the nicest thing to happen. More like vent with flame. Basically, an explosion. Hold on, it gets worse. Lithium batteries give off highly toxic fumes when the explode. Breath in just a little, you get respiratory issues. Severe ones.... that don't go away even several years later. That's not speculation. That actually happened to one of our members.

He then returned a decade later to inform us of all the medical bills he incurred. How he ended up selling off a good chunk of his possessions to pay said bills. And, how he still was suffering with respiratory issues. (And likely will be for the rest of his Life.)

Lithiums are no joke! You have to have a complete understanding of them before you use them. Yes, laptops have 18650s in them. Cordless battery-operated power-tools have them inside of the battery packs. That doesn't mean they're safe, all the time. Just means such products exist for consumers to buy and use.

Was this the person that had the flashlight in his mouth? I think I remember hearing this but never heard he was a member here.

 

[Monocrom]

Was this the person that had the flashlight in his mouth? I think I remember hearing this but never heard he was a member here.

Thankfully no! Not that individual.

 

[TacmedRN]

Oh! You can forget about a fire. Fire would the nicest thing to happen. More like vent with flame. Basically, an explosion. Hold on, it gets worse. Lithium batteries give off highly toxic fumes when the explode. Breath in just a little, you get respiratory issues. Severe ones.... that don't go away even several years later. That's not speculation. That actually happened to one of our members.

He then returned a decade later to inform us of all the medical bills he incurred. How he ended up selling off a good chunk of his possessions to pay said bills. And, how he still was suffering with respiratory issues. (And likely will be for the rest of his Life.)

Lithiums are no joke! You have to have a complete understanding of them before you use them. Yes, laptops have 18650s in them. Cordless battery-operated power-tools have them inside of the battery packs. That doesn't mean they're safe, all the time. Just means such products exist for consumers to buy and use.

There's no need to be sarcastic/mean…I already said I'm a complete noob when it comes to this stuff

 

[aznsx]

Out of curiosity,...

You do know what "...killed the cat", right?; and they have '9 lives'

 

[TacmedRN]

Vent with flame.
You're not guaranteed that will happen. But realistically you are putting yourself in needless danger of it happening. Would you give a sleeping lion a little poke in the balls with a sharp stick, then wait to see what happens next? Of course not. Same thing.

I'm not saying I'm going to do it, I'm not that dumb. But my scientific brain always wants to know the mechanism of action.

 

[Monocrom]

There's no need to be sarcastic/mean…I already said I'm a complete noob when it comes to this stuff

Actually, I was just being blatantly honest. Not sarcastic, definitely not mean. I'm a straight shooter. I tell it like it is. Also, sometimes it can be difficult to convey mood through written text. Had we been face-to-face speaking directly, you would have realized that there was no sarcasm in my voice. Nor anything remotely approaching "mean." Just wanted to clarify that.

 

[Monocrom]

I'm not saying I'm going to do it, I'm not that dumb. But my scientific brain always wants to know the mechanism of action.

Again, not being mean to you. Never once said you were dumb.
People do things oftentimes because they legit don't know any better. That doesn't make them dumb. Doesn't mean they are dumb. Again, just clarifying.

Though it seems as though no matter what I post, you get very easily offended. Very well, I'll let others chime in and leave you alone. Have a good one.

 

[TacmedRN]

Actually, I was just being blatantly honest. Not sarcastic, definitely not mean. I'm a straight shooter. I tell it like it is. Also, sometimes it can be difficult to convey mood through written text. Had we been face-to-face speaking directly, you would have realized that there was no sarcasm in my voice. Nor anything remotely approaching "mean." Just wanted to clarify that.

Thanks for clarifying, text is hard, haha.

I understand that extremes can happen, just like my car could burst into flames randomly, but what is the actual risk?

 

[TacmedRN]

Again, not being mean to you. Never once said you were dumb.
People do things oftentimes because they legit don't know any better. That doesn't make them dumb. Doesn't mean they are dumb. Again, just clarifying.

Though it seems as though no matter what I post, you get very easily offended. Very well, I'll let others chime in and leave you alone. Have a good one.

You could have waited to see my reply that I agree text is difficult to understand tone and thanking you for clarifying. Seems like you are the one getting offended for being misunderstood…

 

[F89]

Although quite clearly stated, the actual risk is serious injury and/or ongoing health issues.

 

[TacmedRN]

I'm given primary cells at work (Surefire brand), so while they are SUPPOSED to be fresh, I'm not witnessing them coming out of the box.

So let's say I have two batteries that are both supposedly fresh, but one actually has about 80% capacity. Is this enough of a difference to cause reverse charging?

 

[thermal guy]

I'm going to get slack for this as most on here feel that 123/ and 3.7 lithium cells are as dangerous as a hand grenade with the pin pulled. That's just not the case. If it were the big boys " Surefire,Fenix, etc" would not be using them. Not that they care about hurting someone but because the lawsuits would shut them down. I have many lights that are 2 X123 and when I swap out the batteries guess what? They are never at the same voltage. One will be 2.8 one maybe 2.4 or lower. So being off a little is not dangerous. I have been on here for 20 years or so and can count on one hand how many " explosions" I have heard of. Not seen but heard. Dont put a dead cell with a live one. You'll live.

 

[aznsx]

...or if you'd like to pursue matching them yourself instead of 'working blind' (which understandably could make one uncomfortable), you may get a voltmeter &/or batt checker which would provide you with some visibility into the processes in play, and a measurement of a metric you may use to accomplish that 'matching' to your personal satisfaction. If you can't completely understand or control it, you can measure it. I can recommend inexpensive Extech DMMs for great value, and some here recommend ZTS as more batt-specific testers, EDIT: which can have the advantage of applying a small load to the cell during measurement .

 

[F89]

Yes, I don't think you're in danger unless there's some basic safe practice not followed.
I'm cautious/curious enough that I'd quickly check voltage with a small multimeter or battery tester.
Sure enough though the danger is real. Mix a bad combination of cells and pull some decent amps and you're upping the odds of something bad happening.