Too Much Runtime!!!

As flashaholics in this age of LED advancement, we are disposed to obsess over runtime. New lights run absurdly long periods of time, especially multiple-mode lights at low output levels. We revel in the ability to handle a three month power outage with the supply of batteries we have on hand. We love excessively long run-times.

But sometimes these lights just run too long! I am trying to use a SF T1A as a battery vampire and the darn thing runs so long the 'dead' cells are collecting faster than I can use them!

Why does this light have to run such a long time? How am I supposed to use up these cells? For once I want less runtime.

Maybe you could just run it 24/7? Or buy more lights with low modes and use them to light your house? You could do away with fixed lighting completely At very least its a good excuse to buy another light.

A few good battery vampires I use that tend to run the "dead" cells down pretty fast are:

Inova 24/7 (runs on red with low-low batteries)
E1B/L1 will suck yer dead ones dry pretty quick
Dorcy 3-Watt

I use up my spent cells in a 4AA battery holder to light up my keyboard and a few other things on my desktop. I have a variable resistor hooked inline so I can make it as bright as I need it and I run it most of the time I am at my computer. I have used up all my spent batteries so now I have it running with some old 1200mah nimh cells I got about 8 years ago until I have more to use. I found normal battery drainers just don't seem to have as much usefulness than setting up something to light a constantly used area to drain batteries for you. Design it so it can also use rechargeables.

Reminds me of leaving left overs in the fridge until old enough not to eat, avoiding the guilt from obvios waste.

Sometimes you just need to allow yourself to toss something that isn't 100% used up.

Less low- level runtime? Heresy, I say! I know how you feel, but I'll take runtime on low over buying new cells any day. I keep a box of dead cells for my Milky candle and my Quark 123, they will get used eventually. 10 year shelf life and all...

Funny thread, OP; gave me a chuckle.
I've been going through the "opposite" phase lately, where I consider that we flashaholics in this age of LED advancement are disposed to obsess over lumens. New lights are absurdly bright, especially those that use CR123 cells. We revel in the ability to light up the entire block with a handheld light, and to see that tree branch 200 yards away. We love excessively bright flashlights.

But sometimes these lights are just too bright! I am trying to use a SF M3LT as an EDC light and the light is so bright that my new cells are depleting faster than I can buy them!

Why does this light produce so many lumens? How am I supposed to conserve these cells? For once I want less brightness.
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Different strokes for different folks, eh?
In reality, I have actually been thinking about how bright my lights are, and how truly sorry I would be in a hurricane or other disaster that lasted longer than a couple days. Sure, I have batteries, but swapping them out 2 hours at a time really stinks. Plus, when you (we) see how little light we actually need to see, we really do wonder why we have these 200+ lumen lights that destroy our night vision, our batteries, wallets, and electricity bills ...
I just set aside my bright lights and use a PALight and Novatac on low to navigate at night. Especially...around the house, which is where I am most of the time at night. I'm talking about navigating with like 1 lumen! It's awesome. My G2X & 6PX pro and Lumintop TD15, LX2, PT2L, G2L 120 & others only get used outside on occasion. Anyway, I think you get the point-- it depends on the "phase" that we all go through, which obviously changes sometimes .

nbp: use a higher level then

herosemblem said:

Why does this light produce so many lumens? How am I supposed to conserve these cells? For once I want less brightness.

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This is a serious question (in case it comes across as rhetorical): Why use primaries in this case? It seems like rechargeables are the only way to go for regular use with primaries in storage for emergencies.

Get some rechargeables. Then you'll never have to worry about trying to use up the remaining juice.

I agree, get some rechargeables for every light that'll take them, and recharge em every Wednesday ( it's my laundry day and I'm up and about every hour or so to check the laundry anyway) :thumbsup: charge the ones you used that week

I have a small portable radio on my office desk. I used to run it on a wall wart but now I use it to run older batteries or as a vampire.

I remember my old flashlights with an incan bulbs draining batteries fast, thats why for me there can never be too much runtime!!

Lesser runtime can only be conceived in two ways, adding inefficiency or adding output. While the former may be discouraged adding more output would mean the circuit will be more discriminating against partially depleted cells. In effect a higher powering light will negate the functions of a battery drainer

So Whats the solution? Buy more low output lights, run them 24/7, unplug a nightlight somewhere in the house and stand a light up in that corner, or by that wall, or hang it somewhere so it illuminates a wall switch 24/7, or a picture, or a mousehole, or the toilet.
I build two-transistor boost circuits to run 5mm LEDs off of anything between 0.7V and 3V: CR2016....AAAA, AAA, AA, C, D, F, CR2, CR123A... etc. Use a homemade colostomy bag to hold alkalines. A postage stamp collector ziploc will do fine. Solder magnets on leads and power it that way, no heat, no wining, turns off when the cell hits 0.6V under load. If it leaks it goes in the bag, not in a flashlight, not on the floor...

With about 10 mouths to feed, I've burned through a bucket of partially dead alkalines in various sizes in about a month. I stopped using cr123As after I switched over to Li-ions.

I have a 2xAAA penlight from LedLenser, not regulated.

One day I just decided to just drain the alkaline batteries that came with the flashlight. So I turned it on and totally forgot about it, next day the light got dimmer, I thought the batteries will die soon.

To my suprise the next day it was still running! and the day after, and after that too. Finally in the 5th day the light got so dim that I would consider the batteries dead. So I turned it off and left it like that. After a few hours I turned it on and the brightness went up again!

I was able to run that penlight for 5 days straight with 2 used alkaline batteries!

not surprising,
the ratio between reduction of output and reduction of current needed, with having a led light up, is not even,
a just slight reduction of output means a much higher reduction of current needed, and when its just a glow coming from the led, it needs about nothing to still run.

I have recently switched to an red A2L from an E1B and LX2 because it has less lumens for usage at night without destroying night vision. The high is VERY bright if your night vision hasn't already been destroyed. Only when I compare it to my LX2 it isn't that bright. You could drain batteries quickly on high I guess, but I am using LiFePO4 rechargeables so that doesn't matter. Runtime doesn't seem important when you can always just pop in fresh rechargeables.

Not to drift too far off topic, but I find the wonderful LF2XT is its own battery vampire! Mine was still working fine on 3 levels, but seemed just a bit "off" on high, so I took the L92 battery out and found it was only putting out 0.58 volts open circuit. Can't imagine a finer circuit than that for still working under those conditions.

Before I took the battery out, I five-clicked it to read out the battery voltage using blink codes, and thought something must be crazy because the first digit was the rapid double-blink - the code for zero, and the second digit was only five. I couldn't believe it was working right, but the DVM confirmed it was indeed accurately measuring its voltage.

I kind of know what you mean. I'm quite a bit OCD when it comes to not throwing away cells that still have "viable" power stored in them. I'd love to make a joule thief that would completely deplete them, but I also have a need to have it DO something with that energy, rather than just drain it for the sake of draining it.

AardvarkSagus said:

I kind of know what you mean. I'm quite a bit OCD when it comes to not throwing away cells that still have "viable" power stored in them. I'd love to make a joule thief that would completely deplete them, but I also have a need to have it DO something with that energy, rather than just drain it for the sake of draining it.

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I think someone needs to make a color changing battery drainer so at least when you gawk at it you can actually admit you are not using the light instead it is a decoration