# Why does every LED flashlight I use flicker and dim so much? **URL:** \ **Category:** Factual Questions\ **Created:** [December 19, 2017, 5:43am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842 "2017-12-19T05:43:40Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Face\_Intentionally\_Left\_Blank](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/face_intentionally_left_blank/32/288_2.png) [@Face\_Intentionally\_Left\_Blank](https://boards.straightdope.com/u/Face_Intentionally_Left_Blank)\ **Post date:** [December 19, 2017, 5:43am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/1 "2017-12-19T05:43:40Z")
It seems like every LED flashlight I buy is unreliable. I’ll be using it, and it will suddenly dim. I’ll bang on it a bunch and it will get brighter for awhile. I’ll try changing batteries, and I’m not sure it helps. Just irritating and unreliable. Eventually I’ll see a sale on another one, buy it and throw the other one out, only for the new one to eventually exhibit the same behavior. My latest one just did it to me tonight, and I am about tired of it. I want one that works, dammit. I thought LED’s use less power. Surely I don’t need to change batteries after much less than an hour of intermittent use? I use name-brand alkaline batteries. ---
**Author:** ![running\_coach](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/running_coach/32/15836_2.png) [@running\_coach](https://boards.straightdope.com/u/running_coach)\ **Post date:** [December 19, 2017, 5:51am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/2 "2017-12-19T05:51:06Z")
What brand are you buying? Or are you buying those super cheap Chinese knock-offs? We’ve got a couple of LED flashlights around the house and three LED bicycle lights on the handcycle and none act like that. The bike lights are rechargeable, the house lights use batteries. Loooong life, either way. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [December 19, 2017, 6:14am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/3 "2017-12-19T06:14:07Z")
Like running coach said, knowing the brand would be helpful, as would the battery brand. Check Amazon to see what other people are saying about it. Also, IME, LED flashlights (the bright ones) chew through batteries pretty quickly. I have a couple of LED Lenser flashlights that I like. I have (amongst others) two of them sitting by my back door for letting my dogs out at night and I have to replace the batteries every two months or so, if I had to guess, never actually guessed. Also, if it makes a difference, one uses 4xAA and the other 4xAAAA and I usually get the “Amazon” brand batteries. If it makes a difference, mine also dim and smacking them a few times will help for a bit, but that usually means it’s time to replace the batteries. However, the trade off is going from [near] 100% to zero instead of dimming. Do you want flashlight to get dimmer over the course of an hour or two of use or suddenly stop working with no warning? ---
**Author:** ![Face\_Intentionally\_Left\_Blank](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/face_intentionally_left_blank/32/288_2.png) [@Face\_Intentionally\_Left\_Blank](https://boards.straightdope.com/u/Face_Intentionally_Left_Blank)\ **Post date:** [December 19, 2017, 6:16am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/4 "2017-12-19T06:16:44Z")
> [@running\_coach](#): > > What brand are you buying? Or are you buying those super cheap Chinese knock-offs? Not particularly good ones, I’m sure. I go by design and price when I buy - I like ones that light a wide area AND have an alternate beam. I didn’t think flashlights required much high-tech know-how to make them work. Might have been wrong on that. I get them at Wal-mart, and the last one was on clearance from a place called “Rural King”. EDIT: No, I dont’ have a brand, not sure they HAVE a brand on them. I wasn’t buying a car stereo. It was a flashlight. . . The current offender uses 3x AA batteries, others have used 3x AAA. ---
**Author:** ![Face\_Intentionally\_Left\_Blank](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/face_intentionally_left_blank/32/288_2.png) [@Face\_Intentionally\_Left\_Blank](https://boards.straightdope.com/u/Face_Intentionally_Left_Blank)\ **Post date:** [December 19, 2017, 6:22am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/5 "2017-12-19T06:22:19Z")
Batteries - Eveready Energizers and Duracells. ---
**Author:** ![snfaulkner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snfaulkner/32/433_2.png) [@snfaulkner](https://boards.straightdope.com/u/snfaulkner)\ **Post date:** [December 19, 2017, 6:31am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/6 "2017-12-19T06:31:34Z")
I use a streamlight pro tac 2l at work. It uses weird 3v batteries. I’ve never had any probs you have described. Pretty sure I’ll still have it after this job ends “accidentally” ---
**Author:** ![Face\_Intentionally\_Left\_Blank](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/face_intentionally_left_blank/32/288_2.png) [@Face\_Intentionally\_Left\_Blank](https://boards.straightdope.com/u/Face_Intentionally_Left_Blank)\ **Post date:** [December 19, 2017, 6:39am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/7 "2017-12-19T06:39:49Z")
> [@snfaulkner](#): > > I use a streamlight pro tac 2l at work. It uses weird 3v batteries. I’ve never had any probs you have described. Pretty sure I’ll still have it after this job ends “accidentally” Dang. . .you know, I typed, “I wasn’t buying a car stereo, it was a flashlight” above. That was my attitude at the time. I’m here to learn if that was a naive position. HOWEVER. . .iffin’ I REALLY have to spend $50 for a WORKING FLASHLIGHT, I think I’ll dig out my big old maglite and be done. It’s big and heavy and unwieldy and intimidating though. ---
**Author:** ![snfaulkner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snfaulkner/32/433_2.png) [@snfaulkner](https://boards.straightdope.com/u/snfaulkner)\ **Post date:** [December 19, 2017, 7:09am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/8 "2017-12-19T07:09:05Z")
> [@Face\_Intentionally\_Left\_Blank](#): > > Dang. . .you know, I typed, “I wasn’t buying a car stereo, it was a flashlight” above. That was my attitude at the time. I’m here to learn if that was a naive position. HOWEVER. . .iffin’ I REALLY have to spend $50 for a WORKING FLASHLIGHT, I think I’ll dig out my big old maglite and be done. It’s big and heavy and unwieldy and intimidating though. This is quite wieldy. Clips on to my ID lanyard. The size isn’t intimidating but its beam is. ---
**Author:** ![snfaulkner](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/snfaulkner/32/433_2.png) [@snfaulkner](https://boards.straightdope.com/u/snfaulkner)\ **Post date:** [December 19, 2017, 7:10am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/9 "2017-12-19T07:10:20Z")
But i will concede that i didnt pay for it. And not sure i would. But maybe… ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [December 19, 2017, 7:15am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/10 "2017-12-19T07:15:36Z")
> [@Face\_Intentionally\_Left\_Blank](#): > > Not particularly good ones, I’m sure. I go by design and price when I buy - I like ones that light a wide area AND have an alternate beam. I didn’t think flashlights required much high-tech know-how to make them work. Might have been wrong on that. I get them at Wal-mart, and the last one was on clearance from a place called “Rural King”. Yeah, that’s the thing. Your old maglight (and any ‘regular’ flashlight for that matter) had a wire that went, more or less, from the battery to the bulb and that was about it. LED flashlights have circuity and resistors and whatnot. Some Chinese mass produced garbage with no name that you can get for 99¢ could have the wrong driver, it could have a bad solder connection that’s running down the battery when you’re not using it (or making a bad connection when you are), it could have crappy LEDs or a faulty switch. It could even be amateur hour circuitry right from the start. Who knows? I haven’t checked, but I’d be willing to bet bigclivedotcom (youtube channel, typed just like that) has taken a few LED flashlights to bits over the years. Not that they’re going to be overly complex, but there’s more going on in there than you’re average incandescent flashlight. ---
**Author:** ![Face\_Intentionally\_Left\_Blank](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/face_intentionally_left_blank/32/288_2.png) [@Face\_Intentionally\_Left\_Blank](https://boards.straightdope.com/u/Face_Intentionally_Left_Blank)\ **Post date:** [December 19, 2017, 7:53am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/11 "2017-12-19T07:53:28Z")
> [@Joey\_P](#): > > Yeah, that’s the thing. Your old maglight (and any ‘regular’ flashlight for that matter) had a wire that went, more or less, from the battery to the bulb and that was about it. LED flashlights have circuity and resistors and whatnot. Some Chinese mass produced garbage with no name that you can get for 99¢ could have the wrong driver, it could have a bad solder connection that’s running down the battery when you’re not using it (or making a bad connection when you are), it could have crappy LEDs or a faulty switch. It could even be amateur hour circuitry right from the start. Who knows? > > I haven’t checked, but I’d be willing to bet bigclivedotcom (youtube channel, typed just like that) has taken a few LED flashlights to bits over the years. Not that they’re going to be overly complex, but there’s more going on in there than you’re average incandescent flashlight. Yeah, that seems to be the case. Now to figure out if I can get a flashlight that works, at a price that a flashlight should probably sell for. I’m not gonna do the flashlight enthusiast thing and go buy $50-$100 flashlights. There SHOULD be a middle ground by now, it’s not like LED flashlights just came out this year. Now here’s another question: Looks like they have LED bulb replacements for Maglites. Drop in the led replacement, and it’s brighter and the batteries last much longer. Wonder if that’s gonna work, or if I have to shake and bang that around too. ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [December 19, 2017, 8:47am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/12 "2017-12-19T08:47:40Z")
TLDR: Get a good flashlight and a good lithium-ion battery. I would recommend [ZebraLights](http://www.zebralight.com/) with rechargeable 18650 cells – they can store much more energy than alkaline AAs. Another good brand is NiteCore, and there are several more if you go to [candlepowerforums.com](http://candlepowerforums.com) Longer version: Not all LED flashlights are made the same. 1. The quality of the LED itself, the little electronic that actually produces the light. Most are crap, especially random Chinese ones from walmart. The best ones are typically from Cree; best means “most brightness per power (lumens per watt, or efficiency)” and also in terms of heat dissipation, quality control, etc. The random Chinese ones are both less bright and more prone to failure. 2. The quality of the other electronics, such as the regulator. While in theory you could connect a LED to a battery directly (and cheaper flashlights do this), they work a LOT better if you have a regulator/LED driver between the battery and the LED. These maintain a steady voltage from the battery to the LED, resulting in a flat brightness curve over time and giving you the longest possible runtime. Without one, the LED will burn really bright at first (possibly beyond its design and thermal restrictions, shortening its lifespan) and then rapidly get much darker as the battery voltage runs down. You’ll typically find these as “regulated” LED flashlights. The better manufacturers will also display their light output graphs so you can see just how brightness will change over time. Ideally you want a flat line from start to finish, not a gradual decrease in brightness. 3. The quality of other parts (housing, wiring, etc.). As mentioned before, a lot of the Chinese stuff is cheap shit that doesn’t have good heat dissipation (very important for the LED and the battery), or loose soldering, or bad housings that allow moisture to seep in, etc. 4. The battery you use. Panasonic makes good 18650 lithium-ion cells; NiteCore rebrands them and adds “nipples” for devices that don’t have spring-loaded contacts. These are MUCH better battery choices than alkaline AAs, which are decades behind, technologically. They are also rechargeable. 18650s are the same type of cells used in most Tesla vehicles (just hundreds or thousands of them). Some of the NiteCore lights have built-in USB ports so you can charge them directly inside the light; otherwise, separate external chargers are available. 5. If you absolutely must go cheap, at least look for three characteristics: A Cree LED, regulated light output, and a lithium-ion battery, preferably 18650. There are third-party knockoffs on Amazon, several of which have a lot of good reviews. ---
**Author:** ![Face\_Intentionally\_Left\_Blank](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/face_intentionally_left_blank/32/288_2.png) [@Face\_Intentionally\_Left\_Blank](https://boards.straightdope.com/u/Face_Intentionally_Left_Blank)\ **Post date:** [December 19, 2017, 9:01am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/13 "2017-12-19T09:01:48Z")
> [@Reply](#): > > TLDR: Get a good flashlight and a good lithium-ion battery. I would recommend [ZebraLights](http://www.zebralight.com/) with rechargeable 18650 cells – they can store much more energy than alkaline AAs. Another good brand is NiteCore, and there are several more if you go to [candlepowerforums.com](http://candlepowerforums.com) Thanks. There is NO WAY I’m paying $90 for a flashlight, but your information should help me improve my decision-making. Saw this, which isn’t too unreasonable, when paired with a little credit I have on my acct. > **[Streamlight 88061 ProTac 1L-1AA 350-Lumen Dual Fuel Professional Tactical Light,...](https://www.amazon.com/Streamlight-88061-ProTac-Professional-Tactical/dp/B01G75P1SC)** > > The Streamlight ProTac 1L-1AA is the newest addition to the ProTac Series and a perfect everyday, ultra-compact, handheld flashlight. This dual fuel ultra-compact flashlight accepts a single lithium or alkaline battery, providing ultimate flexibility... I’ll read around some, check out the candlepower forums, see if there’s something that hits the middle ground I’m looking for - fairly bright, fairly long-lived, fairly priced. If I buy one of these for $30 or more and it friggin’ acts up too, I’mma make a torch. Thanks again ---
**Author:** ![mr\_horsepower](https://avatars.discourse-cdn.com/v4/letter/m/eb8c5e/32.png) [@mr\_horsepower](https://boards.straightdope.com/u/mr_horsepower)\ **Post date:** [December 19, 2017, 9:20am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/14 "2017-12-19T09:20:51Z")
lots of good info provided already. I’ll just confirm that you get what you pay for. I’ve got several 20 volt dewalt led flashlights that take the same battery as my 20 volt tools. I’m often pretty rough on my tools and my flashlights are no different. still work great despite being dropped often. they’ll put a nice defined beam on something an 1/8th mile away (quick guess) and the charge last a long, long time, especially with the 5ah batteries i use. they’ll basically work great until they basically just stop. turn them back on and they’ll turn off in seconds. the flashlights aren’t much, $50. the batteries when i bought them were around $100 each. you’d need a charger too. should be easy to find someone selling a charger on Craigslist. i know i end up with more than i can use, i can’t be the only one. - if anyone uses or buys these, here’s a tip. get some of that protective film they sell for cell phones and put some over the lens. ever since they went to led’s, if you need the lens replaced (for clarity and a sharp beam) you end up replacing the flashlight. the film keeps you from needing to do that. ---
**Author:** ![Reply](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/reply/32/15952_2.png) [@Reply](https://boards.straightdope.com/u/Reply)\ **Post date:** [December 19, 2017, 9:22am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/15 "2017-12-19T09:22:58Z")
What about this one instead? > **[Anker Rechargeable Bolder LC90 LED Flashlight, Pocket-Sized Torch with Super...](https://www.amazon.com/Anker-Tactical-Flashlight-Rechargeable-Water-Resistant/dp/B01KH2JP5G)** > > flashlight $26, Cree LED, comes with a rechargeable 18650 cell (bigger/better than the CR123), adjustable beam pattern, charges via micro-USB. Edit: The LED itself and the battery used to power it are MUCH more important than brand. 18650s are not all that different from each other, but they are much better than CR123s and AAs. Cree LEDs can be MUCH better than the competition. The rest of the flashlight, what it’s actually branded under, is almost irrelevant in comparison: they just supply the metal and plastic. Those are just recycled commodity designs by a few Chinese OEMs. The actual hard work is done by the LED designers (Cree, Philips, Luxeon) and battery manufacturers (often Panasonic, but the Chinese knock-offs are probably OK these days). ---
**Author:** ![Face\_Intentionally\_Left\_Blank](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/face_intentionally_left_blank/32/288_2.png) [@Face\_Intentionally\_Left\_Blank](https://boards.straightdope.com/u/Face_Intentionally_Left_Blank)\ **Post date:** [December 19, 2017, 9:50am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/16 "2017-12-19T09:50:44Z")
> [@Reply](#): > > What about this one instead? > > [https://www.amazon.com/Anker-Tactical-Flashlight-Rechargeable-Water-Resistant/dp/B01KH2JP5G/ref=sr\_1\_1?s=hi&ie=UTF8&qid=1513675272&sr=1-1&keywords=cree+flashlight+wide+narrow](https://www.amazon.com/Anker-Tactical-Flashlight-Rechargeable-Water-Resistant/dp/B01KH2JP5G/ref=sr_1_1?s=hi&ie=UTF8&qid=1513675272&sr=1-1&keywords=cree+flashlight+wide+narrow) > > $26, Cree LED, comes with a rechargeable 18650 cell (bigger/better than the CR123), adjustable beam pattern, charges via micro-USB. > > Edit: The LED itself and the battery used to power it are MUCH more important than brand. 18650s are not all that different from each other, but they are much better than CR123s and AAs. Cree LEDs can be MUCH better than the competition. The rest of the flashlight, what it’s actually branded under, is almost irrelevant in comparison: they just supply the metal and plastic. Those are just recycled commodity designs by a few Chinese OEMs. The actual hard work is done by the LED designers (Cree, Philips, Luxeon) and battery manufacturers (often Panasonic, but the Chinese knock-offs are probably OK these days). Crap, it’s not sold by Amazon so my credit won’t apply, but it does look good, doesn’t it. Even the non-important part of the light is made by Anker, and I’ve liked other products made by them, so that’s a bonus. Giving it serious thought. Getting a little big, though. I put it on the short list - VERY bright, good battery life, rechargeable, replaceable battery. ---
**Author:** ![Face\_Intentionally\_Left\_Blank](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/face_intentionally_left_blank/32/288_2.png) [@Face\_Intentionally\_Left\_Blank](https://boards.straightdope.com/u/Face_Intentionally_Left_Blank)\ **Post date:** [December 19, 2017, 11:47am UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/17 "2017-12-19T11:47:17Z")
You know, reading the reviews of the flashlights on Amazon, my issue seems to be a fairly common one. Ppl complain about the lights suddenly getting weaker for no discernible reason, they’d bang on it or change batteries to little effect, and then they’d give up and give it a bad review. Surely if this happens that much, the flashlight enthusiast community has noted this and maybe knows why it happens. ---
**Author:** ![albino\_manatee](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/albino_manatee/32/2_2.png) [@albino\_manatee](https://boards.straightdope.com/u/albino_manatee)\ **Post date:** [December 19, 2017, 1:22pm UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/18 "2017-12-19T13:22:50Z")
toward bottom of page, various features and terms are discussed … might be worth a read: > **[15 Best LED Flashlights On The Planet (2021)](https://faveable.com/best-flashlights-to-combat-the-dark)** > > We picked the best LED flashlight, the brightest flashlight & the best tactical flashlight out there. Highly recommended as they're affordable & compact ---
**Author:** ![GaryM](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/garym/32/241_2.png) [@GaryM](https://boards.straightdope.com/u/GaryM)\ **Post date:** [December 19, 2017, 2:18pm UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/19 "2017-12-19T14:18:52Z")
On Amazon, here’s a Nitecore MH10: [http://a.co/3RJkNZn](http://a.co/3RJkNZn) Nitecore is a decent brand. This light is capable of an honest 1000 lumen on turbo mode, though not for more than a few minutes without overheating. Runs on either 2 CR123A cells or rechargeable LiIon cells. It can recharge via USB which is convenient. A dedicated charger will be quicker however. It comes with both a set of CR123A cells and the LiIon battery as well. If you don’t like that one, search for Nitecore and there are several pages of lights to choose from. Brighter lights will use up batteries faster Rechargeable LiIon cells will be cheaper to operate if you use the light a lot. CR123A cells are best if you use it occasionally as they will hold their charge longer than LiIon cells. Candlepowerforums is your friend when it comes to flashlights! ---
**Author:** ![Turble](https://avatars.discourse-cdn.com/v4/letter/t/8dc957/32.png) [@Turble](https://boards.straightdope.com/u/Turble)\ **Post date:** [December 19, 2017, 2:56pm UTC](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842/20 "2017-12-19T14:56:25Z")
Here’s the one I have:[ThruNite Archer 2A V3](https://www.amazon.com/ThruNite-Archer-2A-Lumens-Flashlight/dp/B00K70NEHY/ref=sr_1_1?ie=UTF8&qid=1513695120&sr=8-1&keywords=thrunite%2Barcher%2B2a%2Bv3&th=1) Settled on it after spending some hours reading the flashlight (candlepower) forums. It’s good. [Next page](https://boards.straightdope.com/t/why-does-every-led-flashlight-i-use-flicker-and-dim-so-much/804842.md?page=2)