scrutiny on aux led hasn't caught up with proliferation of aux leds

With Wurkkos starting to main stream lights with aux LEDs, it seems like there isn’t enough general scrutiny and awareness on aux LED current consumption. Aux LEDs are kind of a bling feature, but it has an impact on how much you have to babysit the light, and which aux mode you can safely use. In general, I wish reviews of lights w/ aux include:

  • how much current aux LEDs consume
  • time averaged current at different modes of aux LED bright/dim/blinking
  • time averaged current with different colors of aux LEDs
  • aux consumption relative to idle (off) consumption (parasitic drain)
  • is LVP present for all aux modes? Some aux modes? None of the aux modes?

I’ve not seen a single review of lights with aux that really addresses these specs, even on detailed enthusiast light reviews. I might chose not to use certain colors of aux LEDs if they consume too much current and would require too much babysitting. Having too many lights with aux might mean you have to mechanically lock some of your lights because you just don’t maintain the battery on so many high-maintenance lights. But the information needs to be out there to make those decisions. If your answer to high aux current is to just lock out the light, then why get a light with aux in the first place?

Heck, some lights just have straight up flawed aux led implementations because it’s just too high current when it’s in the +12mA range and don’t have LVP on the aux (looking at you TS10!). Speaking of the TS10 - so many people love it because it’s an affordable light that comes in fun colors and bodies. But the toxic combination of low price, high aux current, LVP bug, and low capacity battery format really makes me wonder if everyone fawning over it understands this when they’re buying multiples of them in different color/host combinations.

I certainly don’t think of myself as super educated about the technical aspects of lights, but I feel like there’s a big gap between knowledge and enthusiasm with aux leds. There’s too much enthusiasm and not enough scrutiny, and manufacturers are bringing the bling without putting the necessary engineering to make these aux features practical. These issues also apply to indicator LEDs, but at least indicator LEDs have less room to go very wrong and there’s just a ceiling to how enthusiastic one can get about indicator LEDs.

Here’s some lights with measurements I made. Current measured at 3.6V unless otherwise stated. The D4K is my first and only light with aux LEDs, but I measure my other lights with indicator LEDs because that’s interesting info for much the same reason.

D4K (boost driver, blue indicator, RGB aux)

  • Off: 64uA
  • low (blue): 101uA
  • high (blue): 818uA
  • high (green): 820uA
  • high (orange, red/green): 4.05mA;
  • high (red bright): 3.58mA;
  • blink (blue): 112uA; note 1.1mA peaks
  • blink (orange using red/green): 290uA; note: 5mA peaks
  • blink (bright red): 260uA: note 4.5mA peaks
  • LVP: works for all modes (blink, low, and high), set at 2.8V

ArmyTek Wizard indicator current drain

  • Blinking = 35uA

Sofirn BLF SP36 indicator current drain

  • Off = 136 uA
  • Dim = 186 uA
  • Blinking = 320 uA
  • Bright= 3.06 mA!
  • LVP on indicator set to blinking: 3.0V
  • No LVP on indicator set to bright or low

TS21 indicator current drain

  • Off: 75uA average
  • Dim: 197 uA average
  • Blinking: 184uA average
  • Bright: 1.48mA
  • No LVP on indicator when set to bright.
  • No LVP on dim.
  • LVP on indicator set to blinking, 2.90V

TS25 (Production version as of 2022-11-15)

  • Off: 87uA
  • Blue Low: 131uA
  • Blue High: 3.2mA
  • Blue Blink: 257uA
  • Red Low: 206uA
  • Red High: 6.25mA
  • Red Blink: 450uA
  • Green Low: 213uA
  • Green High: 2.1mA
  • Green Blink: 164uA
  • LVP of 2.8V works at all levels (low, high, blink)

SP10pro: No aux, no indicator

  • -AA (1.3V):
  • Idle = 45uA
  • Moonlight = 3.5mA
  • -Li-Ion (3.6V):
  • Idle = 54uA
  • Moonlight = 1.38mA

Wurkkos FC13

  • Indicator Off = 63uA
  • Blue Button Indicator, low steady = 106uA, good brightness level.
  • Blue Button Indicator, high steady = 3.39mA
  • Blue Button Indicator, blink = 246uA
  • Red Button Indicator, low steady = 185uA, but too dim to be useful
  • Red Button Indicator, high steady = 6.3mA
  • Red Button Indicator, blink = 433uA
  • Green Button Indicator, low steady = 140uA, good brightness
  • Rainbow Button Indicator, low rainbow = 181uA
  • Rainbow Button Indicator, high rainbow = 5.8mA
  • LVP for high and blinking mode kicks in at about 2.7V, consuming 40uA when LVP cuts off indicator light.

As a side note, LEDs are so bright now that I don’t really even consider the lumen output of new lights. But man would I love a comparison of different LED indicator brightnesses. I love indicator lights as much as one can love them. But they need more scrutiny. Where are the specs on indicator lumens and CRI!

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Guilty as charged.

I noticed an incredibly high power consumption of a Wuben light when the switch LED was “breathing” and turned it off. Just checked my review: I completely forgot to mention it.

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Reviewers aren’t thorough enough. Start calling them out on it.

> Here’s some lights with measurements I made.

Thanks for sharing your parasitic drain measurements

> Speaking of the TS10 – …high aux current, LVP bug,

fwiw, the TS10 LVP bug was fixed in July. I agree High Aux is still not practical, it drains the battery too fast.

Low Aux should last about 10 months, which imo is not a problem.

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IMHO, aux leds are for locating the light in the dark, no other function (I’m not in the bling-bling game). Therefore, I think there should be only 1 or 2 aux leds. No need for 6, 8 or 156 aux leds that drains the cell for no valid reason.

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I have had the same wonderment.

Luxwad did talk about and show the aux draw in his D4V2 video

You can see a screenshot HERE

To whoever said it - I feel its really not fair to say “reviewers arent doing a complete job” I was actually hoping that it was just a snarky comment, but I cant tell.

I wasn’t trying to call out particular reviewers or anything. I love Luxwad video reviews and he does do a good job there. But there are lots of written reviews that do not call this information out, which are the ones that are more searchable.

Kuddos to Luxwad for being so detailed. But he is definitely the exception rather than the rule in regards to aux specs details. I think the general statement is still true that reviewers do not analyze aux functionality very well, and stick to the old formula of lumen and current for main emitter.

Aux LEDs are like a SECOND flashlight. That’s not how they are reviewed in general. Even the Luxwad review doesn’t say if LVP protects all aux modes.

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The difference in current consumption between different colors of aux lights is actually noticeable without testing to some degree. I had already gathered that the red aux lights seemed to drain the batteries faster than cyan for example.

It would definitely be nice to have a reference sheet for those concerned about their battery life. My own approach is to check the voltage every time before I put it in my pocket. I also do a physical lockout when I am not actively carrying the light.

I’m OK with bling. A $70 flashlight is 80% bling and 20% functionality if we are totally honest. But the bling needs to be accompanied with understanding and data. Otherwise, it transforms flashlights from a hobby where you make informed decisions about your preferences and priorities to some gross marketing driven smaug-esq pursuit.

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Thinking about it some more, I just realized that a good question to ask is this:

How would you review a flashlight that is designed to stay on ALL THE TIME.

That’s what lights with aux LEDs are. It’s two lights. There’s the main emitter that you apply the traditional set of analysis to that we see over and over again from established reviewers, and there’s also this second emitter that stays on all the time that also requires a pretty thorough analysis that maybe need more thought because it’s not the traditional main emitter analysis because it’s on ALL THE TIME.

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@river345, for TS21 I got 12.9 mA on bright button mode.

You only got 1.48 mA? Which generation TS21 is yours?

I notice you measured at 3.6V. My measurement was with a full battery. Could this be why our results are different?

By 3.6V, I mean my power source was set to 3.6V when I measured the current on the LED. Even if I use the max of 4.2V as voltage source, my current reading should be 1.7mA max. So something is up. My TS21 was purchased 2 months ago. It has a orange color LED. Do you have readings for the other modes (low, blinking) to compare?

What other lights do you have to compare brightness with? I have a SP36 BLF 2nd gen with Anduril 2 and orange LED. The indicator light on my TS21 on bright is slightly dimmer than this SP36 on bright.

I’ll check later, but your other numbers seem close enough to Tom E’s. He was the first person to bring attention to Wurkkos TS21’s now infamous parasitic drain.

I measured with battery in light and rear cap off, one probe on battery negative end, other probe on battery tube and got 12.9 mA. Maybe Wurkkos has fixed this?

Your D4K’s number also seem to be pretty high at 3-4 mA? I only have D4V2’s and I was getting about 1-1.9 mA on the 2 lights that I checked.


“This light has a big parasitic drain, moderately high with the switch LED OFF (116 uA) or on low (180 uA), not visible in room light, and excessively, exceedingly high at 13.5 mA with the switch LED on High.”

Usually I directly measure the aux LEDs with a multimeter in series in the µA range.

If the aux LEDs are blinking I measure them with an oscilloscope and a ~100 Ω shunt resistor (which was very easy with this Armytek flashlight because I could use the magnetic charging contacts with a loosened tailcap):

Some great data points thanks! I’m a fan of low, night adapted eyes friendly colours (red, amber, maybe a yellow) not sure how anyone tolerates the blue, green, cyan even at low levels- especially if kept on a shelf/table in a bedroom!

I love the bling and have/had a lot of lights with auxiliaries. Especially lights I mod / build. However nearly all of those lights have the battery removed or at the very least mechanical lockout when not being carried. E-switch lights are treated the same.

I do have 2 exceptions to the rule, a d4 in the garage and an fw3 in the bedroom. Both set to battery indicator on low. These are for blackouts and are easy to find for my family.

My users that I take to work with me have no aux and are tail clicky’s so I don’t have to worry about battery drain.

I can appreciate it’s good to know the power consumption of aux and the same can be said for e-switch lights.

My biggest gripe about auxiliaries would probably be the limited flexibility of brightness levels

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Extremely well-written and informative exposition of the issue! I'm so glad to see I'm not the only one concerned about unreasonable levels of drain in blingware.

So far my favorite is the blue lighted switch from Convoy, paired with 5A 4-mode driver. Draws around 1mA at full cell and drops pretty quickly when the cell depletes, which 1) saves capacity and 2) makes a great battery indicator--just by looking at the lighted switch, I could tell the cell voltage within 0.1V accuracy.

Having been away from the flashlight world for over 10 years I feel like I’ve woken up in some sort of dystopia. When I left electronic switches were a gimmick regarded with skepticism, people didn’t want parasitic drain.

To come back and find that electronic switches and additional parasitic drain devices are now the norm is rather disconcerting.

I would agree 100% that reviewers (and manufacturers) should publish current draw data on these auxilliary lights and electronic switches. Perhaps a small amount of parasitic drain could be considered an acceptable trade off for certain features and buyers should be able to make an informed decision on that.

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There are different ways that people may want to use Aux and or Button lights, and they require different brightness levels, which will affect runtime. (same is true for main LEDs also)

For example

1. Aux as locator lights, for use with lights that may sit unused for a year at a time.

2. Aux as party lights, to add color patterns to a room, for one night.

3. Aux as emergency Red flashing marker on a disabled vehicle, or carried by a pedestrian or cyclist, to alert traffic.

Each of those applications will benefit from different brightness levels, and different battery recharging intervals.

I think its great that people are sharing parasitic drain info, so we can better understand how to make realistic use of Aux lights.

I get it. High aux levels have their uses, but high aux levels also make LVP and current draw info even more important rather than something that can be brushed off to the side. In fact, if manufacturers are going to make aux lights for the types of uses you listed, I think it’s negligent to not list LVP info and current draw when used with batteries that can be dangerous if over discharged.

I’m not necessarily against high current aux. It’s the combination of high current draw, lack of LVP, and lack of info that is crossing the line for me.