Fenix HM65R Headlamp Review

[Caver Keith]

A gear review from CK

The Fenix HM65R can deliver up to a 1000 lumen beam alongside a 400 lumen floodlight.
It runs off a single 3500mAh replaceable 18650 battery and has a IP68 waterproof rating so it’s good for immersion down to 2 metres.
It weighs in at a mere 150 grams including the battery.
The lamp has a USB C charging port so the cell can be recharged in situ. It also has a LED battery level indicator, a lock out function and comes with a 5 year free repair warranty.
The normal  charging time is around a couple of hours.
Torch supplied by MyFenix - https://www.myfenix.co.uk

Here's my review:

[AdrianTurner]

Recently got one and used it for the first time down Rowton Pot on Saturday and was very impressed, it lit the main chamber up beautifully. I have a hunch that it will become the standard entry level light over the next few years given the price point.

Sent from my moto g(6) play using Tapatalk

[Caver Keith]

I'm have a hunch that it will become the standard entry level light over the next few years given the price point.

I agree.

[andrewmc]

The only downside to the Fenix lights is that the runtimes are basically lies - the lamp output drops rapidly, which makes it last longer but it isn't at the lumens you expect. Fundamentally a single-cell 18650 light is only going to put out so much light for so long (I suspect all LED lights are of similar efficiency). Of course you can bring spare batteries...

edit: after a bit more Googling, the 'runtime' is the time the lamp will work for before output reaches 10% of the original. So they might say '400lm for 22 hours' but they mean '400lm initially, 40lm after 22 hours and probably a lot less than 400lm for most of the time'. The lamp maintains constant brightness levels, I think, but steps down on a regular basis.

[Caver Keith]

Fenix are quite open about runtimes and output levels. This graph is included in the instructions.

[ZombieCake]

The graph is quite interesting, the discharge line and lumen output lines look quite flat until you look at the vertical scale  y axis and how the numbers are divided up, and measure back.  Not quite equal gaps between each 100 lumens....
Still at least they published it.

[ttxela2]

I've got one and have used it once so far on quite a wet mine trip. I was pretty impressed with it and it survived the trip pretty well too 

[Ian Ball]

That graph is difficult to read. Two non linear axis.

A 3500mAh 18650 has a recharge cycle value of 500. And if you go for the ARB-L18_3500U it comes with a built in charger which I've not seen before!

Though a decent charger would be a wise investment I think especially if you use them for flash guns and have a few to charge before a trip.

[andrewmc]

That graph is difficult to read. Two non linear axis.

It _might_ be a log axis, although I would have to measure it to check. It is, in any event, a terrible terrible graph and a cynic might argue it is there more to mislead than inform.

Which isn't to say that the light is bad - just don't expect to get 400lm out of a single 18650 for a long (8 hr+) caving trip with _any_ lamp. On the other hand 400lm is more than you need for general walking...

[Chocolate fireguard]

They aren't log axes - a glance is enough to show that.

I'm normally a graph fascist but I think there is enough information on that (sketch?) for anyone who is contemplating buying one. I wouldn't say there is any intention to mislead.

[JasonC]

The graph would suggest that the spot goes suddenly from ok to nothing when the battery runs down.

I'd like to think that's a false impression and it's smart enough to automatically turn to low before that happens so you're not suddenly plunged into darkness.  On the other hand, the little (ok, cheap) Fenix I keep as a backup tends to do exactly that - ie dying without warning.

[Stevie5tapes]

I recently bought one of these lamps. I was impressed with the light output compared to my old lamp (wisdom caplamp) but I was disappointed with the battery life. My first trip with the Fenix and the lamp lasted 4 hours before switching to emergency mode. But having said that I had selected the wrong light mode.

I’ve ordered a spare battery and next trip underground I’ll experiment with the different light modes to see how long I can get the battery to last for.

[Canary]

The graph is reasonable. If it didn't have compression on both axis it would be a rediculously Long X and an unreadable Y axis

[andrewmc]

The graph is reasonable. If it didn't have compression on both axis it would be a rediculously Long X and an unreadable Y axis

If the axis aren't set in a mathematical way (linear, log or something similar) it isn't a graph, it's a sketch. If it was a real graph you could work out the lumens at every point in time. Because it does not appear to be, you only know the values at the fixed points.

[ttxela2]

Well as a real world guide it lasted a good 4 hour trip with me splashing around and turniing it up and down constantly to take photos and forgetting it was turned up for quite a while most of the time. On exit it appeared to have lost only one of it's charge bars on the indicator thingy.

I might draw a graph when the nurse lets me have my crayons back.

[mikeveal]

I'm interested in one of these. So interested that I joined up just to comment.

The headlight uses a XP-G2 (170lm/Watt wide angle) and a XM-L2 (180lm/Watt spot beam) LED from Cree.
The battery is 3.5Ah at 3.6V, giving roughly 12.6Wh.

Looks like the graph has a line for 400lm. 400 lumens at 170 lumen per watt is 2.35W.

12.6Wh / 2.35W = 5.35 hours.

You'll never get that in practise as the LED efficiency won't be 170lm/W at 400 lumen and the battery won't give 3500mAh at this current. Then there's the efficiency of whatever circuit they are using to dim the LED.

So, yes, the math stacks up with the fact that they must drop power output to get those run times. It also shows that the light output & runtimes achieved are respectable for a single cell lamp.

A pity you can't tell it how long your trip is and let it adjust the runtime to suit.
Or better have it automatically drop out of high power mode into an auto mode after, say 5 mins. High power mode gives you 400lumen. Auto mode gives you xx hours of runtime (from when the battery was fully charged).

I wonder what processor is inside? There clearly is one. Could be ripe for hacking!

[royfellows]

I wonder what processor is inside? There clearly is one. Could be ripe for hacking!

Doubt its possible as Fenix torches don't dismantle so I expect a headlamp to be the same. I found out the hard way when I tried to upgrade an old Fenix torch.

[mikeveal]

Dang.
Oh well, I think I'll post a letter up the chimney for Santa to read anyway.
Cheers fellers.