Lumens vs Runtime vs Application. Your thoughts?

Sometimes runtime wins over sheer lumens. Take this Coast G20 going for $3 at Home Depot. Someone on BLF recently had a big mighty complaint about it not putting out the lumens advertised. So I got one to see what the big deal is.–1&keyword=G20&storeId=10051&N=5yc1v&R=203460505

Ok, I agree with the poster that it doesn’t put out 36 lumens. More like half that or even less. But then I got to thinking. If this did put out 36 lumens it wouldn’t get 12 hours+ runtime on 2 x AAA alkalines. Then I got to more thinking. This is afterall just a pen light. An inspection pen light at that. What should I really expect and want in an inspection pen light? To me lumen output isn’t everything especially when one considers the intended application. I think sometimes we give too much emphasis on brightness at the expense of runtime considering again the application.

Point being sometimes less lumens and more runtime is appreciated. And sometimes when I want to inspect something like in a tight small enclosure (think CPU enclosure) the last thing I need is a bunch of bright light reflecting back and blinding me or affecting my night vision. This light for that sort of application works great. For $3 it really works great. The other bonus is that it’s put together solid. Now I’m running 2 x AAA eneloops and I bet the runtime goes more than 12 hours even. What’s not to like? Plus it has a removable nice clip. I’m happy.

So in this case I think less is more. Thanks Coast for mis-advertising the lumens. If it had been 36 lumens I would’ve been disappointed. I know, this flies into the face of flashaholics anonymous like a runaway freight train. :wink:


This confirms it, youarenotawhackjob. You make too much sense. One of the hardest things I had to do on the last mod was remove a 7135 chip from the driver for less output(makes me cringe just thinking about it), but it was for a work light and I should have removed 2 or three. For someone with outdoor night work needs this does not make sense but for indoors or case work yes. Thank goodness for modes. I can have my cake and save some for later too.

I love low lumens and prefer 1xAA/14500 lights with single digit lows and moonlight modes. As a camper I’ll use a light continuously at night, and with little ambient light, just letting my night-adapt is the best free flashlight turbo charger and battery extender. One Eneloop for week’s camping trip is not uncommon, and with night adjusted eyes, its really kinda cool to be able to see the other 280-degrees outside of the flashlight’s 80-degree beam.

Course, having ~150 lms NiMh (~300+ Li-ion) on tap to see those distant eyes reflecting back at you helps too.

NAWJ, I agree-output shouldn’t always be the primary consideration, if ever!

texaspyro was probably put off by the fact that the G20’s egregiously inefficient driver leads to low overall efficacy.

Solo moonlight mtb rides. Turn off the lights, wait a bit, and melt into the night. I still want max lumens for the descents, though.


As you said, it depends on application.

I like to have a low low lumen small edc light in my pocket, I know it will run forever on a fresh AA and has enough light to be perfect as a backup light, in case something happens to the main flashlight, or for walking without disturbing night vision. Lately I'm using a Thrunite T10 for this, and love the very low low 0.09lm. (high 115lm, med 9lm)

On the other hand, I generally need very good lighting for inspection purposes, so the main flashlight is usually something capable of at least 500lm and with decent throw (need to have a small bright hotspot)

The pen light you were discussing, in my opinion, is only too big. If I can have the same low lumen output and long runtimes in a smaller pocketable package, I'd prefer it even if more expensive. 2xAAA is too long to be comfortable, and a single AA has much more capacity

If they had said it was a 10 lumen light, great. But they said it was a 36 lumen light.

And at the current that the G20 pulls, there is no reason it couldn’t be a 50 lumen light.

I look at it just a bit differently. If it had been a 450 lumen penlight really only putting out 350 lumens the difference would be about ‘par’ for the course with Chinese over exaggerations. But since this is a really low output penlight, losing 20 lumens is a big deal considering it had so little to begin with. lol

Nonetheless, for $3 I think it’s still a great deal. It’s solid. You couldn’t make it for that much that’s for sure.

Btw did you try using 1 x 10440? :wink:

It doesn't have to be expensive.

The L10 sold by Jake, a member here, sells a $20 flashlight that starts from 0.09 lumens and goes up to 120 lumens. It uses a single AA and is the lightest flashlight I have at a skimpy 20 grams. It's tiny too.

The BLF A8 doesn't quite go as low, costs about the same, goes much brighter and uses a 26650.

A 25 cent coin light puts out roughly 8 lumens and probably more with good fresh batteries, and I've used the red light version for well over a dozen hours. I used the white light version for a month while backpacking, and only stopped using it because I misplaced it.

I agree with this, if all you want is single digit lumens on disposable batteries then there is no need to be at BLF, home depot or ebay or countless other retailers have you covered and you can pursue other hobbies.

120 lumens is a lot more than the 16 lumens of that pen light. :D I get you though. The BLF A8 probably puts out 500 lumens. I haven't seen a test to confirm though. $23 and you get it all.

I now exclusively use li-ion powered xm-l lights at work, a c8 with a nanjg and a jm07 clone that’s soon to get a nanjg, what they both need is e1320’s moonlight to super bright program adding to be perfect.

Believe it or not, 500 to 600 lumens under a van is not ideal, low is much more comfortable, never mind if your inside a small regenerated box (shiny reflective surfaces).

The blf a8 has been used almost exclusively on low or moonlight for the same reason.

Lumens in all the right places. Sometimes less is more! :slight_smile: