It's been a couple of weeks since the Fenix HM23 arrived (thank you once again Fenix UK and UKCaving!) and I feel like I can give it a good review.

First impressions are good: it feels robust and well made, with a firm elastic headband and a soft and comfortable rubber holder. It comes with a bog standard alkaline AA battery (which I'll swap for a lithium AA when it runs out) and Fenix's warranty.

For its first outing in the dark I took it for a run and compared it directly with my usual running torch, a Black Diamond Spot (2018). The HM23 is noticeably more comfortable to wear and doesn't bounce around on my head at all. The colour temperature is a bit warmer, and the beam shape is much better, with a more uniform coverage and less of a bright spot in the center. The programming is much simpler too, a long press to turn the torch on/off and a short press to cycle between the three brightness modes. The lowest brightness is still bright enough to be useful (even to run by). The middle brightness is slightly too bright for my liking, and I'd only ever use the high mode in exceptional circumstances. Photo attached shows the brightness levels (and my dog staring at squirrels).

I enjoyed running with it so much that I chose it for my other runs that week and a few dog walks. I used the middle brightness mode pretty much exclusively and noticed no change in the brightness until half way through a run it dropped to the lowest mode where it stubbornly remained. This was a bit sudden for my liking - I'm used to being able to roughly gague the battery life of my torch when I leave the house by it's brightness (and the LED indicator), but the HM23 doesn't do either. I walked the rest of my run. When I got home I hung the torch up, still on the lowest mode, and impressively it stayed on for about another 48 hours with very little change in brightness until just before it died.

Today I joined Tom and tamarmole, of this parish, for a nosey around a lovely little deathtrap in the Tamar valley. I took the HM23 to see how it felt around my neck. I tucked it into my buff whilst I was underground and had forgotten I was wearing it by the end of the trip. It didn't seem to mind the incredibly acidic mine water we were wallowing in either. However I did worry when putting it back in my bag that it might turn on accidentally, as it doesn't feature a lockout.

So, my advice is: take a spare battery if you're using it regularly, or treat it like a proper backup and only use it if you really need to so you know it's fully charged, which is what I'll be doing

Thanks, Ari for posting a review of your prize.  I can send it to Fenix who will be chuffed, I'm sure 

To every prize winner who goes out of their way to post a photo/review/thank you - thank you!  Companies are so supportive of UKC and it's great to see forum members appreciating this. 

I found Aris' review particularly helpful; thanks.

I find myself writing part 2 of this review in darkness from the center of a Cornish woodland. The pleasingly long lasting moonlight mode that so impressed me in my last review might be contingent upon using an alkaline battery. Tonight (with a good quality rechargeable AA) when the torch dropped to the low setting I just had time to think "ah silly me, this moonlight mode will be tricky to navigate by" before it died completely. Don't get me wrong, it's my fault that I went for a walk with a torch with a low battery, but I could really have done with a bit more warning than that. Thankfully the light pollution from Truro is so pronounced that it's like walking by candle light - if you were caving though you'd be royally f*cked So the lesson from tonight is, the clever brightness regulation on this torch is so clever that it gives you next to no warning that it's on its last legs (if you're using a rechargeable battery, at least).

I've just bought myself an HM23 to use as a spare and was interested in Ari's mention of using a lithium battery with it. A lithium battery would seem ideal, given their long shelf life, high capacity and (I think) they work well in high drain equipment, like a lamp. But... the spec sheet for the lamp advises caution when used with a 1.5v lithium battery. It goes on to state :

Disposable lithium battery: it can be used if the voltage is below 1.5v: or may cause damage to the lamp if the voltage exceeds 1.5v.

Is this just Fenix covering themselves or is there a possibility of a nominally 1.5v lithium battery giving out a higher voltage in some circumstances? A website I looked at seemed to suggest this but I don't have much knowledge of the subject so I could be misunderstanding what it's saying.

The spec sheet recommends using a 1.2v Ni-MH and states that a 1.5v alkaline battery is usable.

I emailed myFenix in Cardiff to see if they had any more advice/information about using a lithium battery and got a very rapid response. Unfortunately they were just as non committal about lithiums as the spec sheet but did recommend using a good quality Ni-MH such as an Eneloop over an alkaline as they are better in high drain situations and also hang on to their charge well, of course.