Flashlight with extreme battery endurance??

Hi all,

For ultra trailrunning (up to 180 miles so it takes multiple days) i am looking for a flashlight (besides a headlamp) with extreme battery endurance.
Want to use this light as back-up in case of emergency when my headlamp (still looking for a good one) for any reason stops working.

My requirements:

-. max 15cm (about 7 inches)
-. up to about 500-700 lumen is absolute enough
-. Waterproof (preferably with official IPX8 rating)
-. neutral white light (3000k-4000k), NOT clear white or cool white or whatever they call it.
-. Top endurance battery capacity, preferably 40hrs and up

If possible with red and green led.

Not really looking for an insane flashlight that can even blind airplane pilots.
Waterproof (not a diving lamp though) and extreme battery endurance is key for me.
Preferably one that also gives a good flood for my surroundings instead of just a small spotlight that reaches 200 meters.

My budget:

about $20-$50 max.

Are you looking for 500 lumens for 40 hours, or a light with a 500 lumen mode, and a lower mode that lasts 40 hours?

500 lumens for 40 hours is 20,000 lumen-hours, which at 150 lm/W (exceptionally efficient for a 500 lumen flashlight) requires 133 Watt-hours of power, or ten 18650 batteries. That’s probably larger than you had in mind.

4000K is probably the best choice.
More efficient than 3000K and still to the warm side of neutral.
Pleasant CCT.

Forget about 500 Lumen.
Way too much for extreme duration.
But, it would be good to have the ABILITY to use 500 to 700 Lumen for short periods, of course.
But for comparison, my hobby headlamp has 2x 18650, totaling some 6500mAh, and it can run 1 Watt (approximately 120 Lumen ?) for 16 hours on one charge.

why can;t you charge during the day time?

why isn;t 8 to 12 hours enough?

i would also guess 100 lumens is enough for darkness
it would certainly make some of your other goals easier to reach

otherwise you are [500 lumens for 40 hours would be about 60 watt hours, which would be about 6 18650 cells worth of weight and cost.
a little solar or AC charger would let you get by with 1 cell ]

also how come you don;t just get an extra headlight , for ‘backup’, if the one you have meets every other requirement?

it seems like you could not replace the function of a headlamp with some hand carried 3 pound thingy —which you also hope to not even need

would you not have to carry the backup light while running too?

wle

I think just about any budget/Chinese flashlight that is IPX8 is going to say it’s a dive light (whether it really is or not). Is there some specific feature of dive lights you are trying to avoid?

^ Weight

It’s a matter of watts used versus how many mah’s the battery is. Some lights have more efficient drivers but it’s mainly the light output per current it’s drawing to battery capacity. If you want the light to last for days either lower the output to just the amount of lumens you can get by with or buy a light with multiple batterys or one large battery.
.
Drawing 350 ma making around 200 lumens (depends on led used) using a 3500mah 18650 that’s about 10 hours of runtime. Half the current draw and that’s 20 hours of run time from a single 3500mah 18650. Add another battery and that’s 40 hours.

Hi all thanks for the replies.
Really appreciate it.
I’m a real newbie when it comes to flashlights and headlamps so most likely i am too excited with my expectations to get about 500 lumen for 40 hours.
I’ve seen flashlights with 13000 lumens that does 3 hours on a battery so i thought if i would not be too greedy with my lumen requirements that might save a huge load on the 26650 battery :smiley:

I already thought of using multiple batteries and load with a powerbank but the issue (besides the load of the powerbank) might be the backpack shaking all around, seen the micro USB ports on the batteries itself that might break while running and charging.

Sofirn SP36 blf on a low mode should sustain quite long, or a BLF Thorfire Q8, or a convoy 4x18A on a low mode with some decent cells, Samsung 35e for instance.

Remember that are the Chinese 13000 Lumens.
We use the Ansi/FL1 standard though

Unfortunately we probably can’t tell you which ones.
HKJ does review drivers, but mostly those used by homebuilders (not according to availability in flashlights) and a lot of those listed are no longer available.

I wish we had a list of flashlights ranked by driver efficiency.

You have been misdirected by “chinese” lumens.
By zak’s rational: better battery (18650) for endurance = 3500 mAh, efficient emitter ~ 150 lumens/watt:
A Cree XLM-2 emitter at 450 lm draws 1.0 amp and its efficiency is 140 lm / watt), thus 450 lumens ÷ 140 lm/watt = 3.2 watts
A Samsung 35E battery has 12.167 watt hours @ 1.0 amp discharge, thus 12.167 watt hours ÷ 3.2 watts = 3.8 hours

Sorry the technology isn’t as advanced as you expected. However, at low mode (0.4 watt - lowest tested data) a XLM-2 efficiency is much higher (not linear) and would give 12.505* ÷ 0.4 = 31 hours. *Battery can give more energy at lower discharge rate.

So a “Convoy S2“:Convoy S2+ Schwarz XM-L2 7135x8 3/5mode EDC LED Flashlight 18650 Sale - Banggood Deutschland and a ”Samsung INR18650-35E”:http://www.mtnelectronics.com/index.php?route=product/product&path=59_88&product_id=920 battery. On low mode (~40 to 50 lumens) should hold up 40 hours. On medium will give 400 lumens. It’s cheap and very rugged. There are many tints available - the L2 T6-4C (~4400ºK) is an all around good illuminator.

Edit: The S2+ has linear driver so is constant output as the battery drains. Also quite good efficiency.

flashlights with 13000 lumens that does 3 hours on a battery
a lot of specs are just fake: 13000 real lumens would need about 20 leds and be using about 50 watts, would also need water cooling or a fan
and 15 18650 cells just to supply all the watts

wle

i still don;t see why you don;t just get a 2nd headlight like you already have

instead of having your back up unit weigh 20 times as much and put out 50 times as much light for 5 times as long :slight_smile:

wle

A power bank would be a very inefficient way to carry energy for your lights for many reasons. You would want to carry as many fully charged battery’s as are required for the duration. Unless there are pit stops where you are exchanging gear etc. Warm light is better. I would agree with others that a spare headlight is better then an extra flashlight.

Have you looked at the little solar panels meant for backpackers?

Take a look at Zebralight light. Others include Acebeam and Fenix.

I know about those fake lumen claims.
Trustfire is a notorious one 13800 Lum TrustFire 12X CREE XM-L T6 (13800 lumens)
That’s why i’m glad i found this forum to actually see the reviews including the real measurements.
That said, with tons of brand and types it would probably take me weeks to read them all.
Instead i created this thread to see if anyone know a solid flashlight that does meet my (too optimistic) requirements. :wink:

@Sidney Stratton thanks i’ll read reviews of Convoy S2+ first.

Several reasons.
A flashlight (or even 2) easily fit in the pocket of your blouse, and so it does on a front pocket of a backpack for immediate access.
A good headlamp requires more space, most likely is heavier, does up to 4 hours max on 400 lumen and is more expensive (talking about a good one, not a plastic $2,95 thing).