Beginner’s question: If protected cells are generally safer than unprotected, why use unprotected at all?
I can think of a couple of reasons:
- Bulk. Protected cells are longer than unprotected cells, due to the circuit board which must be mounted onto the end. Some flashlight designs do not allow for this, and the protected cells will not physically fit.
- High current drain. The protective circuit is designed, among other things, to prevent the consequences of a short circuit. Newer high-power flashlights can draw many amps of current during normal operation. An unprotected cell is required to deliver this amount of current because a protection circuits cannot distinguish between legitimate high-drain and a dead short.
I have a question regarding an 18650 battery that seemed to overcharge. I pulled this battery from a lap top pack. I believe its a Sanyo
numbers on it are “ocnm4e9” and under that is “148750”
I use an Xtar VC2 charger.
The cell wasn’t over discharged, according to what the charger said when I put it on to charge. Also, it was still hitting max brightness in the light, an Astrolux S1.
The cell charged to max volts appropriately, but the capacity was at 4,100mah and still going when I took the cell off the charger. It was slightly warm.
I wonder how that Mah reading is possible and is the cell damaged? Is it safe to use?
Capacity is measured when discharging, not charging. Else a Pb-acid battery that trickle-charges forever would have a huge capacity.
I wouldn’t worry too much.
I know this is an old post
Sounds like the battery had very high resistance stopping it from reaching full charge
I’d never use a laptop pull in the Astrolux S1
LG Stay Safe Battery website.
I found LG’s Website www.staysafebattery.com.
It is informative in the way of lithium-ion battery safety, from a CYA sort of perspective.
My take away from watching the videos is “Don’t say we didn’t warn you”, as perhaps a legal defense posture.
There is a link to the LG Lithium Ion Battery Safety Guide which is a warning not use their bare cells.
Chuckle. Yep, that’s a keeper. The illustration at 2:21 is …. instructive.
Though I wondered how the arc was maintained — is that CGI or is it real?
In other thoughts: If I install enough of the antigravity floating cells shown in the video, I’ll have my long-promised flying car!
I have one of those TURNIGY pouch cases and wanted to know is it ok to keep 18650 , NiMh, and Lithiums together in there,
….or should I just get separate cases for each?.
thanks.
No problem but don’t just throw the cells in there because they may short.
thanks . is there a way to stop that?.
cheers Agro.
F.e. keep them in plastic boxes. I guess that’s the best combination of safety and usability. Or use a rubber band to keep them together. Or put them in zip bags.
why not use protected cells?
cost
protection is usually unnecessary in a flashlight
capacity is lowered, or it may be too long
you want high drain, which isn;t unsafe usually
good questions
respect for your taking the time to learn more
my thumbnail impressions (not an expert)
LiIon safety in a nutshell
do not drain the battery/cell below 2.5 volts. IF this happens, there is a risk that during recharge the battery will overheat and explode. (IF the overdischarge created electrical reversal inside the cell)
LiIon types
ICR cells require protection…
IMR and INR are safer chemistries, and are often unprotected.
Lights designed for high output, call for high drain cells, and those are unprotected. Anduril lights tend to have built in LVP (LowVoltageProtection)
If the IMR/INR cells are used in a light with built in low voltage cutoff… then all is well for the battery.
separate from issues related to overdischarge, lets consider heat
Anduril lights are capable of high brightness and high heat. They should therefore only and always, be carried locked out.
It is bad for the battery to overheat, so, never tailstand the light on high output levels. Instead, always hold the light in hand, when using hot outputs, and turn the light off, before it gets too hot to hold.
There are also thermal regulation features in Anduril, that let you set the step down temperature, lower… And it is possible to set the ceiling output, to a low enough level not to burn delicate parts. Anduril also lets you select the startup brightness… it can be set low enough not to burn holes in stuff.
just for illustration… what not to do
- Set the light up to come on at turbo, disable thermal stepdown, and drop the light in your pocket, unlocked…
2. When using the light on Turbo, when it steps down, turn it off and back on, over and over again. Wear Gloves, and just hold the end of the tail, where it is coolest. Thereby defeating the thermal stepdown and creating a dangerous overheating condition.
If you read this far, I imagine you can see the errors of those ways 
Enjoy your KR4! 
Good stuff Jon, well put.
Hmmmmm…. Interesting video. I have always heard it is a bad idea to charge a LiIon battery with low voltage. ??? 
I know, I think the person that made the video is misinformed.
good link
some details about different types of “Lithium” cells
1. CR123 is a Lithium Primary (non rechargeable), with a nominal voltage of 3v
this is a disposable battery that was popular before rechargeables became available
there is still a large number of lights (Surefire), and people that use them… particularly in places like LEO and Military applications, where batteries are stockpiled and provided for free
2. LiFePO is a Lithium cell (rechargeable), also with a nominal voltage of 3v
this is a rare cell, used in security cameras that were originally designed for CR123, but whose owners seek a more cost effective, rechargeable option. They cant use 3.7v LiIon because the voltage is too high for those old circuits
3. LiIon is a Lithium Ion (rechargeable), with a nominal voltage of 3.7v
these are the “typical” cells in high output flashlights
multifuel lights
there are many CR123/16340 lights on the market
one example is the Jetbeam RRT-01
the lights work with both types of cells, but due to the difference in voltage, the maximum output is different between the two types.
the voltage difference makes it difficult to design a protection circuit inside the light, because the LiIon cell does not like to go below 2.5v (for recharge safety), whereas the CR123 does not care if voltage goes below 2.5v, since the cell is disposable.
these dual fuel lights usually recommend using only Protected LiIon… because the driver cannot distinguish.
there is one dual fuel on the market that has a sophisticated enough set of options, that it can use UnProtected LiIon and also CR123. That is the HDS/Novatac design.
The Anduril lights only work on LiIon, they are not CR123 compatible. Anduril lights have built in LVP, that would get confused by a CR123 (the LVP would think the battery is discharged, when it is not)
LiFePO4 is usually rated at 3.2V as nominal, not 3V.
You can find a lot about it on my website.