Question about runtimes and what they actually mean?

[CobraMagnum]

Hello, everyone. Hope you're all well. I'll try to make this as simple as possible.

Almost all flashlights that you buy, whether online or at a store, have a runtime printed on the packaging and/or in the instructions. And sometimes, of course, if the flashlight has multiple brightness levels, it tells you the runtime on each brightness level.

My question is pretty simple. If you have a light, and it says (for example) runtime on high: 10 hours - does this mean that it will operate for 10 hours at the specified brightness AS WELL AS maintain that brightness for those ten hours? Or does it mean that it will run for 10 hours, but the brightness will steadily decrease over the course of that 10 hours?

Any additional information you can provide about runtimes will be appreciated! Thanks!

 

[Showngo]

This really depends on the light itself. Generally I don't trust the high end claims as lights step down fast for heat reasons. Here's a reviewer who measures this a bit if you're interested https://zeroair.org/2021/10/20/eagtac-d3c-titanium-flashlight-review/#Power_and_Runtime

 

[Lynx_Arc]

Most often store bought lights these days are using ANSI FL1 spec which equate run time as run time down to 10% of the starting lumen output and the starting output is usually the highest mode. So if the light says it puts out 500 lumens the run time will be until it drops to 50 lumens regardless of step downs etc. Now there are some manufacturers that give run times for each mode till it drops down a mode, but some give the run time till it drops down to nothing.
In other words best to find a review of someone who gives graphs of output over time in each mode.
One other thing is lights often give runtimes using only certain batteries and often they are alkalines (alkaleaks) and using rechargeables will give you less run time in some instances as they tend to start at lower output but don't drop in output much till batteries are depleted. I tend to measure the current draw of the light on each mode and then taking into account the capacity of the battery I can estimate the run time at that output level.

 

[fuyume]

Hello, everyone. Hope you're all well. I'll try to make this as simple as possible.

Almost all flashlights that you buy, whether online or at a store, have a runtime printed on the packaging and/or in the instructions. And sometimes, of course, if the flashlight has multiple brightness levels, it tells you the runtime on each brightness level.

My question is pretty simple. If you have a light, and it says (for example) runtime on high: 10 hours - does this mean that it will operate for 10 hours at the specified brightness AS WELL AS maintain that brightness for those ten hours? Or does it mean that it will run for 10 hours, but the brightness will steadily decrease over the course of that 10 hours?

Any additional information you can provide about runtimes will be appreciated! Thanks!

Don't buy a light if the mfg doesn't publish at least a brightness over time graph for it. And go by the graph, not by the number.

 

[3_gun]

FL1 spec which equate run time as run time down to 10% of the starting lumen output and the starting output is usually the highest mode.

Close. The spec is run time equals 10% of the lumens at 30seconds from on. It also applies to any level they wish to test.

So if a light has a turbo of 4000 and at 30sec it's dropped to 1500 the 10% mark would be 150L not 400L. I was doing run time tests with some of my lights (posted in General) of just the run time at 1 level until it stepped down or was noticeably dimmer with non regulated lights. All claimed times include light levels well below the start level

Turbo & high are technical but not useful levels of light when it comes to run time, mostly. Even my Acebeam E70 which does really well with heat management & battery life (5k/mah 21700) will only give you about 70minutes of 1000+L when using high, then over the next half hour or so the light fades until it drops to the low level of 50L.

They claim 105minutes which is pretty close as long as you know/remember the last 30-40minutes are going to be light levels WELL BELOW the 1300 you started at with a fresh battery. Oddly I found my light will actually exceed the claimed total run time at 180L by over a hour BEFORE it steps down. It also had a better run time at 650L with a 3000mah battery than it did with a 5000mah battery BUT at 180L the larger battery did better as you'd expect

There are a few lights which will give you over 1000L for the life of the battery but few if any would be an EDC sized light. Look at the claims & graphs and then knock off 25% or more of the claimed time to get an idea of what the constant light might be at levels below 1000L. Above 1000L it would be an even higher %. And until you actually test your light with your battery it's all just a guess

 

[Lynx_Arc]

Close. The spec is run time equals 10% of the lumens at 30seconds from on. It also applies to any level they wish to test.

So if a light has a turbo of 4000 and at 30sec it's dropped to 1500 the 10% mark would be 150L not 400L. I was doing run time tests with some of my lights (posted in General) of just the run time at 1 level until it stepped down or was noticeably dimmer with non regulated lights. All claimed times include light levels well below the start level

Turbo & high are technical but not useful levels of light when it comes to run time, mostly. Even my Acebeam E70 which does really well with heat management & battery life (5k/mah 21700) will only give you about 70minutes of 1000+L when using high, then over the next half hour or so the light fades until it drops to the low level of 50L.

They claim 105minutes which is pretty close as long as you know/remember the last 30-40minutes are going to be light levels WELL BELOW the 1300 you started at with a fresh battery. Oddly I found my light will actually exceed the claimed total run time at 180L by over a hour BEFORE it steps down. It also had a better run time at 650L with a 3000mah battery than it did with a 5000mah battery BUT at 180L the larger battery did better as you'd expect

There are a few lights which will give you over 1000L for the life of the battery but few if any would be an EDC sized light. Look at the claims & graphs and then knock off 25% or more of the claimed time to get an idea of what the constant light might be at levels below 1000L. Above 1000L it would be an even higher %. And until you actually test your light with your battery it's all just a guess

Yeah I forgot about the 30 seconds bit for ANSI but I think for the most part lights bought in stores or that have packaging listing runtimes based upon ANSI don't have a turbo mode or super high modes that cave greatly after 30 seconds.

A lot of lights I've seen don't even list ANSI that have uber high 1000+ lumen modes. Since you can't really base experience with a light on ANSI these days I find it only useful as the high point and based upon the battery type use consider it from there. In other words ANSI didn't help but to try to reduce lying about the highest output of a light.

 

[bykfixer]

Also note, the distance of the beam shown is how far it can light an object about as bright as moonlight, so keep that in mind also. There's a given number but it's pretty much "moonlight bright", so the object would not be lit very much at that distance.

 

[thermal guy]

I pay no attention to advertised run times. Because I use my lights and need to know what they will do every light I get gets batteries put in them and I test them. This way I know she will run for whatever time at whatever level. It's good practice and it's the best way to know.

 

[Lynx_Arc]

I think if you have a light that runs off lithium ion only you can often look at low and medium modes and get accurate run times at those levels. Turbo is a mode that most lights step down and for some even high mode throttles down after awhile. Luckily for me I bought my 18650 lights based upon usable lumens at around 30-150 lumens not 300+ which even though useful in cases with bad light pollution or long distance which isn't the norm for me.

In other words if run time is important, you also need to determine output (accurately) at that run time as often lights with multiple modes don't list lower mode output as ANSI and in testing in reviews we have found that it varies considerably often it is less than advertised so if you need no less than a certain output a light that advertised exactly that output with a runtime may come in a little dimmer, perhaps due to ratings made with cool white emitters and you chose another tint like neutral or warm white which usually is less efficient with overall lumens trading output for color accuracy.

To put it bluntly you just about have to search out unbiased reviews to get a good picture, don't depend totally on reviews on sites that sell the products either as some can be fake or get a freebie to review it.

 

[Poppy]

Please see the Flashlight reviews section of our site.

In particular, members Selfbuilt and SubWoofer usually include runtime reviews, you may also do a search in that section for any particular light you may be interested in.

 

[KITROBASKIN]

Don't buy a light if the mfg doesn't publish at least a brightness over time graph for it. And go by the graph, not by the number.

This eliminates a lot of decent flashlights as well as bargain basement types, seems like. Not to mention that data can be massaged for profit if not outright deception. One element perhaps not yet discussed on this thread is that the human eye does not necessarily see the way graphs and marketing hype show. The lumen numbers can change a significant percentage but our eyes do not perceive that much change, especially if the distance to object of interest is pretty short.

Once it is understood that the 'agreed' upon flashlight standards were set to primarily sell flashlights and hopefully offer an apples to apples comparison (if manufacturers are honest) then we can relax about promotional claims, and find a torch suitable for our needs based on the type of emitter, reflector/lens, power supply, and the efficiency of the electronics (to some degree).

There is no substitute for experience and some members here at CPF can provide useful perspective if specific parameters are stated in their quest for a flashlight to meet a specific need. Any corrections/refinements to this post are most welcome.

 

[fuyume]

This eliminates a lot of decent flashlights as well as bargain basement types, seems like. Not to mention that data can be massaged for profit if not outright deception.

1. Yes. Yes, it does.
2. That happens regardless of whether or not the mfg publishes a graph, but the ones who publish graphs are much more reliable about self-reporting than the ones who don't.

This is the graph of the PD36 TAC that Fenix advertises. You can at least see from the graph immediately that the 3000, 2000, and 1000 lumen modes step down dramatically and in a relatively short period of time, and that the 350, 150, and 30 lumen modes do not. And this is borne out by real world experience.

I bought my PD36 TAC for the runtime at 350 and 150 lumens, not for the claims of 3000 lumen maximum brightness for a few seconds. But, from the graph, you can see that the 1000 lumen mode will actually give about 700-750 lumens for a reasonable amount of time, and even output the full 1000 lumens for at least a few minutes before the first step down.

 

[importculture]

I never liked the ansi fl1 rating system. I know it's great that there's a standard of rating lights. But the parameters doesn't really give me an accurate gauge of runtimes at a certain output. I wish they just told us how long a light can run at a certain level before it can no longer output that level. I understand that manufacturer's need their lights to sound appealing with long runtimes but it feels deceptive. Thankfully we have a lot of great reviewers both here and on youtube that do the actual runtimes. Thank you to all the great reviews doing the work so we can make a better educated purchase. Thank you so much! I really appreciate you guys and this forum!

 

[Poppy]

fuyume,
Thanks for bringing this up.
I recall when first seeing that Fenix posted runtimes, that I hoped that others followed suit.

Do you know of any other major manufacturers who post run time charts?

 

[hsa]

Streamlight used to put charts on the package or on line for most of their products. Now they just do some of them.