If it’s not the case, then my other question would be: can one flashlight (that runs on 1 x 14500 for example) work with whichever chemistry (ICR, IMR, INR, LiFePO4 etc)?
I’ve read about the pros and cons of the various lithium ion battery chemistries but can’t find whether they are interchangeable in terms of compatibility.
The voltage of a LiFePO4 is different from the others, so a LiFePO4 would not work well in a light designed for the other cells
LiFePO4 nominal voltage is 3.2 volts, the other cells that are most;y used in flashlights are 3.6 volts nominal volts. So a LiFepo$ cell will appear to be partially/mostly discharged to a light designed for the other cells.
Just buy known brand names from reputable sellers.
The actual manufacturer of the cells do not build them with protection circuits. Those are added by re-sellers.
yes ICR, IMR, and INR are all interchangeable voltages… LiFeP04 is different
however, imho ICR MUST be Protected, and the protection chip usually (not always), makes them longer. Lights that use UnProtected length IMR and INR may or may not have enough spring travel to allow using longer Protected cells
Usually when buying a light, one determines based on the battery recommendation from the manufacturer, and from reading reviews, whether the light lacks internal protection, and the recommended batteries therefore will be protected…
certain lights, particularly older ones that are dual fuel capable (CR123a/16340 and AA/14500), have no Low Voltage Protection (no LVP) in the light, and Require protected batteries, to prevent overdischarge
For example Nitecore lights that are CR123a compatible, generally should use Protectected cells when on LiIon. Also EagTac lights that are dual fuel compatible, including AA/14500, should be used with Protected LiIon, because the light itself has no LVP circuit. Fenix has similar lack of LVP circuit in the light itself, and relies on the Battery to provide overdischarge protection
some IMR and INR can also be Protected, and they also are often longer (not always), than unprotected.
for example, my first generation Jebeam RRT-01 does not screw shut, if I try to use some Protected 18350… I make a habit of reading the battery specs to check how long they are, as part of my shopping research.
it IS possible to use Unprotected batteries in Unprotected lights, but it is up to the Operator to take responsibility to prevent overdischarge, or risk venting with fire during recharging of an overdischarged cell… especially Unprotected ICR… which I think (hope), are no longer sold.
also, some lights, such as my first generation Jetbeam RRT-01, which has no built in protection (and can use CR123a which are single use disposable and can be drained to lower voltage than LiIon) Can have unintended sudden shutoff caused by the LVP in a protected battery, under certain circumstances
so, there are times I prefer to use unprotected IMR or INR in my RRT-01, because I dont have to risk being left in Sudden Darkness in a potentially inconvenient location. There are times I choose to use 18350 (unprotected), for the larger capacity and runtime, instead of using a protected 16340 that has a lower runtime capacity (mAh)
so, even though it is safer to prevent overdischarge in my unprotected RRT-01, by using protected 16340 batteries… I sometimes intentionally use Unprotected IMR or INR 18350…
I will not risk using Unprotected ICR… those are the ones as far as overdischarge hazards… most likely to vent with fire during recharging, after having been overdischarged. (below 2.5V)
IMR and INR are more tolerant of overdischarge without catastrophic failure… than ICR
for example, my Wurkkos TS10 does not need protected batteries, because the Anduril firmware in the light itself has LVP… however, it Does also work with some Protected batteries (that are not too long), and the light does not trip the protection…
For example, the USB rechargeable Lumintop 14500 is a protected battery that is not too long, and works in a TS10.
but in my RRT-01, protected batteries can sometimes trip protection when they are on a low output and then I suddenly dial up to maximum output…
the protection gets tripped by my demand for higher output than the depleted battery can provide. That means I might end up in sudden darkness.
so, lights that use Anduril, do not need protected batteries, but can use them if they are not too long
otoh, my RRT-01, and many Nitecore and Fenix dual fuel lights, have no built in protection in the light itself. Prudence dictates that protected batteries are required for safety… but IF the operator is alert and recognizes when battery voltage goes low, it IS possible to use unprotected
To help focus your questions to a practical application, maybe give a specific example for which particular light you want to explore battery safety options.