Are we there yet? - 500 Lms hi on 1 battery 4 hours runtime. No heat...

LED tech seem to be more than quadruple in 2 years its seems. It was about 2 years ago that lux1 - 100 lms lights were top of the line and now xml2 and xpg2 are at the top lumen producers.

Can we do 500 lumen one 18650/14500 cell and 4 hour run time yet?

That would be an idel EDC for me. Can you make me one?

I can’t wait til next year when someone make one that does “do 1000 lumen one cell and 4 hour run time”.


A triple XP-E might give you close to 500 lumens with a quite decent battery life but 4 hours of runtime on a single 18650 at those levels, I don’t think is possible.

Nope, 500 lumens will drain your battery in an hour or so. In a small EDC form factor the LED will be pulling around 2.5A-3.0A to get 500 lumens out the front.

4 hours runtime with the best 18650 at 3400mAh,

is 850mA current, far from 500 lumens.

And just to dig a little deeper…

XP-G isn’t going to hit 500 lumens OTF within rated specs. XM-L2 is more efficient and can so let’s look at that. At 2A a U2 bin gives you 728 lumens. I usually use the rule of thumb of around 70% of that being OTF based on a very old thread I remember from CPF. That gives you about 510 lumens OTF. 3400 cells in HKJ’s battery comparator are giving around 3.1 Ah at 2A draw…closer to an hour and a half if you just divide. Trustfire 26650 discharge test I found (Trustfire “5000” mAh) had 4.2 Ah at 2A. Even that’s only 2+ hours before you deal with dropping out of regulation, power losses in the driver, etc.

Touch over 2 years ago was the announcement of the XM-L with the XP-G already being on the market. Things have moved fast but not that fast. :wink:

Battery issue aside, thermal issues are probably going to be a problem if we are talking about a small, EDC-style light. Simply put, a small light isn’t going to be able to dissipate the heat of an LED running at 500 lumens. So the light will need to drop
in brightness in order to prevent damage.

You can get 250-300 lumen for 4 hours on an 18650.

For a single battery, you’d need a 32600 (lithium D cell) to get close, there’s not enough of them being made to get real quality mah from one.

See below, all that extra size and only 5000mah

A thread on 6000mah 32650 batteries

4 hours at 500 lumens, may be possible with 2-4 cells but not one, not yet

…and IMO that’s not that bad at all 8)

I wouldn’t say LED technology has quadrupled in 2 years…. more like 8 years: still an awesome achievement by any standard.

As for 500 lm for 4 hours:

The best 18650 battery out is 12 Watt hours, this leaves you with 3 watts per hour if its to run for 4 hours. If we assume a driver efficiency of 90-95% that gives us ~2.7-2.85 watts.

Now lets look at the LED: 500 lumen from 2.7W = 185 lumen per watt, anyone want to guess the efficiency of an XM-L2 or MK-R at 25°C?

Granted unless you live in Antarctica and have a torch made of pure copper you wont see those numbers… but at the current rate we should see an LED capable of it within 2 years…. and that’s not factoring advances in battery technology.

I can tell you right now that 4+ hours at 500+ lumens is COMPLETELY possible with 3 full capacity NiMH D cells in a Mag with the Malkoff XM-L2 drop-in. But this is a larger light than most people around here seem to want to bother with. On the other hand, as has been pointed out, 4 hours at 500 lumens might be possible on one cell if a 32600 is built to its full potential. But whether or not such a cell (and light to make use of it) exists is another matter.

I’ve been reading up on various lights, run time and out put and found this thread about SC600.
I have the light but lacks the hi capacity battery to test this, but according to the test it run on hi -out put of 500 lms with 2900 mAh cell. With 3400 battery, it would seem to be able to run for nearly 3 hours if not more?

If we can find some more refinements in LED, Circuit, Cooling etc, some one should be able to do it.” reference post”:Zebralight SC 600 "W" is ready for preorder...!.

May be mkII can do it? any one have any data on this light?

I think the answer is yes, to an extent.

Heat will always be a side affect though and while current led technology is improving, it isn’t changing this fundamental.

Also I think we need to discount the 14500, as it’s many times less capacity than an 18650 and would be entirely different to try and attain similar results with (700mAh vs 3400mAh).

Personally I think if extended run time is needed then it’s all about the regulation. Both MagLite and Led Lenser use a step down or gradual fade regulation for this exact purpose.

This means you can turn on a high powered light and you’ll get lots and lots of light, as time goes on with the light activated it’ll step down, this is normally not noticeable by eye. But will greatly increase runtime. If you “need” max output simply turn the light off and on again.

That way it gives the user control over runtime and max output.

The title says one battery…….

pedantic mode on a battery is a collection of cells, how many parallel wired 3400mah cells can you get in a rucksack? pedantic mode off


What I find remarkable is that there are two inexpensive choices available right now in common US brick and mortar stores that can do 500 lumens for over 4 hours (per manufacturer’s ansi FL1 claims). No ordering from specialty shops or overseas needed. Of course, they take 3 C cells instead of the desired single cell, but pretty darn close.

Home Depot Defiant

Costco Feit Electric 500 lumen

The Feit is small enough to carry around in a bag, the HD light is larger.

I find it mind boggling how far we’ve come in the last ten years.

I’m surprised to not find a lot more talk about PWM and perceptual brightness. It’s not like we only care what the light measures like, if it also looks like something better, do we?

An XT-E with a good PWM (very short pulse width, much longer spacing) at a decent enough rate to not flicker can have be perceptually very bright, but not pull much power from the battery.

Like the KD C8 XT-E R5 model, the “medium” on mine lasts for 8 hours (HiMAX 2600 mAh, thanks Don), and it looks like it’s around 450 lumen.

A 26650 light built with three CREE XM-L2 U2’s Could Almost do it.

4000mAh Cell at average of 3.6V. Can’t take it all the way down, so real capacity is perhaps 3600mAh. That gives us 12.9 Watt Hours.

Over 4 Hours, 3.24 Watt Hours per Hour

Find a good 90% efficient Driver, and we’re left with 2.9 Watt hours per Hour to the emitter.

Figure we need 625 Lumens to get 500 Out the Front.

At about 450mA, each XM-L2 will be making a little over 200 Lumens. So that gets us our 625 emitter lumens.

Power draw will be 0.45A * 3 * 2.8V = 3.78 Watts.

So, we’re not too far away from single cell, 500 lumen, 4 hour capability. All it would take is a bit more battery capacity, and we’d be there. A 5000mAh LiIon could manage it.


I only want to defend your comment here.

It is Vitally Important that those of (us??) who know better, always speak up when we find Error.

How else will those who Don’t Know, ever Grow?

Just sayin’…