I was wondering if anyone knows of a low temperature 16340 battery.
I've got a Fenix headlamp (HM50R V2) that takes this size of battery. I thought about just using non-rechargable lithium CR123A batteries in it for cold weather, but the Fenix website cautions against this.
Anyone have advice about low temperature battery options for this headlamp?
I own and use (constantly) 2 HM50R v1 headlights, and am also interested in possibly also getting 1 or more of the v2 version which has replaced it, so I'm interested in these related questions.
First, let me start with 'I don't know' regarding your specific question. I'm familiar with other 3.7V Li-ion cells (particularly 18650 size) which are optimized for low temp operation (and advertised as such), but don't recall seeing any 16340 cells advertised with that 'feature'. There may be some, but I'm unaware of them. Someone else here may have knowledge of some if they exist.
As a 'side' point, both the v1 & v2 versions are advertised as supporting LFP (LiFePO4) 16340 cells (which I use in a number of my lights), and which are of course secondary (rechargeable) cells (although they cannot be recharged internally in an HM50R). Although the LFPs are generally of lower capacity than other '3.7V' chemistry cells, they MAY offer better low temp characteristics than the 3.7V LI-ion cells, and therefore MIGHT be an option for low temp environments - in lieu of CR123A primary cells. The 'operating range' temperature specs on my K2 LFP 16340s are very close to those listed for primary CR123A cells, but I don't have any exact specs for how their performance (may) actually be affected by such low temps. It's an open question, and hopefully someone else here may know more regarding LFP cells in low-temp applications. They could be an alternative option to 3.7V Li-ion cells in cold weather, particularly until we can understand the totally ambiguous 'Caution' regarding use of CR123A cells in the v2 version (which, like you, I would like to use in cold weather).
To your point regarding the use of primary CR123A cells in these lights, they are specifically recommended for use in the v1 version, specifically for use in low temp applications; however there is a 'Caution' regarding using them in the v2 version light, and probably like you, I am interested in getting more info regarding that very ambiguous (unexplained) 'Caution' note on the CR123As in the v2 version.
I'm going to attempt to get clarification from Fenix regarding the CR123A 'Caution' note in the v2 documentation, and will inform the forum when I get that. In the mean time, we'll see if any others know of a 'low-temp' 3.7V 16340, and you might want to explore the LFP16340 option, and others here who (hopefully) have more expertise on cells / batteries than I do (which isn't much) may be able to speak to any low temp advantage they MIGHT offer vs other 16340s of the 3.7V type chemistries.
In the mean time, stay tuned for whatever info I can get from Fenix re: the use of CR123As in the new v2 version. I think it could be as simple as a 'language issue', but want to clarify that with Fenix themselves before suggesting it. One cannot guess or speculate when product liability issues are potentially involved.
