Any Danger in leaving on when away from home?

LED Flashlights – General Info 18650 Flashlights
1

In checking the run times of various battery and light combinations I decided I would check an Ultrafire 2100 light and a Trustfire battery with the light on low. I suspect this combination would run well over 24 hours, and I may need to leave during the day.
Is there any danger in leaving the light burning while I am away?
Thanks,
Jerry

2

There's always 'any danger', but I'm sure you will be fine, spontanious combustion of Li-ions, even Trustfires, is extremely rare, and driver electronics, even when cheap chinese, are also not known to suddenly do nasty tricks.

3

Probably fine. To be safe, put it in the middle of your garage while you are away, or the kitchen sink, or a ceramic bathtub…

4

Is the Trustfire battery protected? If not, it could be discharged to much (protected should shut off on 2,6-2,8V).
This should be the only problem.
The UF2100 works fine (I never run a runtime on low, but it's one of my edc and I haven't any problems since 3 years).

5

Thanks for the replies. I had in mind putting it in my garage when away. The battery is protected.
My interest in running it on low is in consideration of an extended outdoor trip. Personally I would use AA lights. With alkaline batteries run times with single AA alkalines can exceed 20 hours. That almost precludes the need for spare batteries.

However, when the subject arises there are always those who state they would take 18650 lights. While those lights will run long times, unless one just wants to play with lights I do not think they are the logical choice considering that you do not want to totally deplete them and the need for recharge. I am also mildly concerned with safety.

S and R folks may need that light and power, but hikers do not in my view considering the long run times of AA alkalines.

Thanks, again,
Jerry

6

Jerry,

There is always a danger. The risk vs gain is just not enough. I do not know many of the UltraFire lights to have low voltage protection and I do not trust battery protection as a "be all" - I have had three failures with battery protection.

If you have to go to work just shut it off and turn it back on when you come home. Besides if it runs out of juice before you get home it will not be that accurate anyway.

7

thanks, bugsy.
Jerry

8

Thanks for the input, bugsy.
Jerry

9

What would you use the light for?

Very important question. In some cases alkalines would do fine.

The main problem with long runtimes on alkaline batteries in single AA lights, I assume is light output. the output is greatly reduced, probably to the point it won't be useful for anything other than looking at a map, or as a tent light.

10

The li ion choice has a lot to do with voltage of the LED. Using batteries that are native to that range makes it easier to use capacity (I think). AA need to sacrifice some of the amps available to up the volts from 1.4ish to 3v which results again I think, in a shortened runtime compared to itself if it didnt need to up the volts.

You then can get much more lumens too as you have the grunt to over drive the LED which again is pretty much a goal round here. But as another approach to the same benefits of li ion, a good li ion with a std driven LED will run for ages on mid modes. Sacrifice a bunch of lumens (yes Ill say some hail Marys or something as penance for that remark), you get run time.

As I said, I think. Or at least I think I think.

Edit: Youve been here since 2012, its likely none of that is news to you.

11

Hi ChibeM,
In fact I would not use it for anything. I never use li-on batteries, and never a 18650 light. As I said when the question of camping or hiking arises someone always says they would carry an 18650 light. I am just curious if a person could get much more than with AA alkalines. I would suspect an appreciable amount, but have never tested it. I realize the 18650 battery has a greater capacity, but do not know of the current draw. For me the 18650 batteries would be more trouble than the would be worth to me. I wonder if one would need to keep up with the remaining charge of a li-on battery?

For me, I would not even consider li-on batteries. A single AA light, such as my Quark 4 sevens mini, and one other would take care of me for any camping or hiking trip I would go on. I have always done things that are physically tiring, and want to sleep at night instead of test the power of lights.
The output of a modern single AA light is more than I have ever needed. I would probably use it on med, and low. Rechargeables would also be more trouble, and of less run time than alkys.

Ejected Filament, thanks for the comments. For most anything I do I prefer run time to output and throw. I am finding that AA alkalines give a lot of run time, over 20 hours on high and more on mid or low. I would not need anything else.

Thanks,
Jerry

12

Conversely, I almost exclusively utilize Li-ion flashlights primarily for night fishing. My needs are more towards a very high output spotlight with reasonable runtime. Along with a headlamp leaning more towards longer runtime, with the option of higher output if needed. I usually bring a change of batteries just in case, but I’ve only used those on extended trips (2-3 nights in a row).

The main difference between alkaline and Liion flashlights is the output. A x2/4/8 AA light just can’t maintain the high amp draw for long. If they do hit high numbers it’s usually with a steep Stepdown shortly after hitting turbo. Liion hits those peak numbers and holds them all in a typically more compact formfactor.

A great thing about a lot of flashlights is a built in low voltage warning (even a fair amount of low budget lights). The light will start flashing in some sequence or another to indicate low voltage. Even if the light doesn’t have the low voltage warning you will almost certainly notice the far lower output of a nearly depleted Liion battery.

If high output isn’t a top priority Alkaline/NiMH is probably the way to go since you can still get pretty nice output along with the versatility. You might want to look into bringing a high output lumen blaster along with your AA lights though. If for nothing else, it’s quite a lot of fun hurling light to some far off distance or making the night into day for everything in the general vicinity. :bigsmile:

13

I can see the choice for you, having done some night fishing. No doubt there are uses for the 18650. As to hurling light, I am always too tired to do much except to eat, get ready for next day, and sleep. :bigsmile:
Thanks for the input.
Jerry