So my kids enjoy using their flashlights close to bed time, but fall asleep with them on, and we go through a lot of batteries. I thought about getting them each a shake light and got one of the Everlast lights that WM sells to test it out. Beam was narrow and not very bright...and the best part...shake for two minutes to get three minutes of light!

After I returned it, I found a crank light at WM. Cost about half the price...has three LED bulbs, can use just one or all three bulbs at once. It says it will last for an hour at best...they're awkward and not very sturdy...but I have a feeling my battery cost will go down!

Not impressed anymore with shake lights .

My kids do that same thing and I bought a set of those "as seen on tv" (That's a good thing?!?) shaker lights for this Christmas.

In this case, "shake for two minutes to get three minutes of light" is a desirable feature. Kids have virtually unlimited energy, especially when they are supposed to be getting to sleep.

I ruled out any type of crank light as the ones I've seen are pretty noisy.

A cranked generator and a linearly moving magnet both work on the same Faraday principle.

The wire in the shaker lights doesn't store the energy. (Yes inductors do store energy but not enough to run an LED for minutes.) There must be a small rechargeable battery or capacitor in there.

When (not if) my kids break these I'll do thorough analysis.

actually the better "shakelight" is VERY good for an emergency kit (keep them away from your compass) the faraday coil charges a capacitor which in turn supplies current to the led (the better lights use a better cap.). Yes, the do only give aprox. three minutes of light, but this is better than no light at all.

Mostly. I think there is a context that makes sense: The third world. If I had no resources and batteries were unobtainable, a light that was nearly indistructable and worked basically forever and didn't cost anything to run would be valuable indeed. One that you could pass down to your children.

On the other hand, flashlights have come a LONG ways recently, and it is possible to get lights that are very cheap to run, or can be stored long term.



The first light that comes to mind is the Princeton Tech Attitude. It has 3 x 5mm LEDs and runs on 4 AAA cells. It outputs a resonable amount of light for close work like reading, is waterproof, simple and nearly bomb proof. And it even comes in semi-translucent colors! :-)

Other posibilities are the Gerber Infinity Ultra with a white LED. This light has one 5mm LED and runs on a single AA battery. While it outputs less light, it still outputs enough to be useful and has a long runtime. This light is also waterproof and nearly indistructable. The main downside is it would be a lot easier to lose.

If the kids are a bit older and can be trusted to take care of things a bit more, a Mini Maglite with an Opalec Newbeam bulb replacement is very nice. While only 3 x 5mm LEDs, it outputs a reasonable amount of light and transforms the Mini Mag into a very sophisticated beast. The best part is that it has a regulator to maintain constaint output for about 10 hours. This light is very efficent and can run from very cheapo batteries.

Good luck!

-john


EDIT: I'd also suggest you avoid lithium powered lights for kids. They can be dangerous if damaged.

I don't know, but I found a place where I could get the smaller sized shake lights for $5 for 3 of the lights. I was thinking about getting some for nieces/nephews as well as a couple to put in BOB or storage.

Theres a valid performance and monetary reason for many gear items. A Mora knife for your first survival seminar until you can afford and know what knife will be your primary blade is an example. Then there is the 'gee wizz' stuff that seems to hold an advantage such as shaking, solar or cranking power sources. 3 minutes give you the advantage of seeing your spaceblanket shred in winds better faced with a cheap surplus blanket and a old D cell flashlight at minimum.

I've got one of those Gerbers and like it. Actually the battery LEDs that my kids use are smaller than that...Dorcy AAA. And yes, there have been many a night when I've turned over a spare light because one kid or the other couldn't find theirs...

They actually lost one of those big crank lights for a few days! While keeping track of the AAA lights!

I look forward to building a house in the next year or two, so each child can have their own room...two in the same room now is a clutter nightmare!

It seems that many/most brands of shake light are quite fragile and are basically toys. The Nightstar brand seems to actually be a decently made product from what I've read, although I've never handled one. That said, would I consider them a joke? Well, the cheap ones, definitely yes. The good ones--well, it's hard to find a good use for them. Their beams are narrow and quite dim and they don't run very long. In spite of their advantages, those disadvantages make them pretty useless for most situations unless you were Tom Hanks on Castaway or something like that.

But, for a child that likes playing with flashlights and who will tend to leave them on accidentally, why not? Then again, how about just using rechargeables in the flashlights they might play with?

Don't remember just how small your kids are, but we've got two kinds of auto shutoff lights for our 4yo and almost 3yo. The first doesn't mention the shutoff feature on the web page, but it's quiet (see #2) and has three colored lens filters: auto shutoff kid light . The second (little tikes) you can find at wallyworld - squeezing the handle opens the animal's mouth (dinosaur, tiger, etc...), turns on the light and - most annoyingly, makes it roar. Over and over and over and over....

No, not hard core or even soft core CPF material here. But they are kid friendly, easy on batteries and a source of entertainment and morale for the little ones (and not so little ones). We tried one of the shake lights from Sportsman's Warehouse - they liked it, but the novelty wore off pretty quick. It's in the bottom of my go bag, not a great light, but it's a light source and I never have to worry about having batteries of any size, shape or voltage. That's the biggest draw for me: no matter what (almost), I've got a light.

(edit) Don't remember the brand of our shake light, but our guys gave it the kid tested seal of approval last Christmas - beat the daylights out of it and it survived short dunks in the toilet and the tub. If anyone wants to let my guys test their favorite $200.00 torch under these conditions, let me know...

I have several of them - not sure what brand. They all have both batteries and "shake" capability. The light is not bright, and the "shake" light doesn't last real long - but a minute of shaking gives you some light for a bit.

Remember that these are not meant to light a football stadium at 1 am. They are meant to provide enough light to get by in an emergency - and for that they are, IMO, just fine!

I have used rechargables...my problem was that I only had enough for the lights they used, and if they would need a charge right before bedtime...
Was going to get some more last time I went to WM, but couldn't seem to find them...

The problem with rechargables for this kind of thing is that rechargable batteries don't like to be discharged to zero. The kind of thing that likely happens when they fall asleep with them on. So, this wouldn't be a good idea unless the light had an auto-off.

-john

I'm aware of this, but in my own experience, I'm not sure it's really something to worry about in this particular case. And I'm talking about regular AA NiMH that you might buy at the supermarket, not something like more exotic rechargeable Li-ion batteries, which I would be very careful with in terms of charging or deeply discharging.

I use some Engergizer AA NiMH in a weather radio that is always on in stand-by mode. I continually let the batteries drain until the radio dies, swap with an already charged pair, and then put the depleted cells in the mini-recharger that it came with. I repeat this cycle about twice a week and I've been doing this for a couple years on the same set of batteries and have not noticed any appreciable decrease in runtime compared to when the batteries were new. Of course, maybe the radio doesn't discharge the batteries quite as low as some energy-sipping LED flashlight might, so maybe it's not a good comparison. The kids could get incandescent flashlights, which will still drain the batteries, but probably not down as low as an LED would.

In any case, while I would generally want to heed the advice that the longevity of NiMH batteries is related to the depth of discharge, I'm not sure I would worry about it with the kiddies' flashlights. In fact, I would think that they would grow bored with wanting to play with flashlights every night before the first set of rechargeable batteries eventually wore out. <img src="/images/graemlins/smile.gif" alt="" />

My experience is that they are just fine when you first get them. A shake now and again provides plenty of light to walk the dogs.
Unfortunately; They don't hold up. At some point you begin having to shake the heck out of them to get any light at all. I suspect they have a capacitor that wears out (fairly quickly) or goes bad.
Gave up on them for batteries.

Jon

Keep in mind, though, that a regulated LED flashlight will simply turn itself off when the voltage drops below a certain level, leaving what should be an ample charge left in the NiMH batteries.

That would be weird if the capacitor wore out. Y'know the maddening thing about many shake lights? They're actually run on button batteries! It makes the LED look bright when you're in the store and when you first use it. I don't remember the particular lights, but I remember reading about this somewhere. Oh, I think it was on the Nightstar website. It's possible that your light was primarily run on batteries, and had a really cheap, essentially useless "shake light" mechanism for show. So, shaking it really didn't do much, although it might have generated a tiny amount of power, so technically it was a shake light. But once the batteries run down, you're out of luck

Without trying to sound like a commercial, NightStar is way better than the other shake lights. They claim to be the original and that others are infringing on their patents. I have one of the full-size older ones (newer ones are said to be brighter) and love it. It uses a capacitor. It uses repulsive magnets at each end instead of clunky rubber bumpers for the main magnet. It's solidly built, feels well-made. Completely sealed, including the switch, which uses a magnetically-activated reed switch. It is decently bright, which means it is fine for navigating around the house or back yard or walking the dog. Would I like to be brighter? Last longer? Sure. But for what it is I am very satisfied.

Steve

Disclaimer: I have no relationship to NightStar in any way other than being a customer.

Some may use a battery as the storage method. Regardless of the reason, the ones using batteries should probably be avoided in favor of the more reliable and longer lasting capacitor.

-john

Okay. I dug out one of my shake lights. It doesn't have a brand name on it, and I've long since discarded the packaging. I bought it at a surplus store (on Morse Road near Cleveland Ave in Columbus, if you'r interested) and it came with a keyring LED that has a carabiner-style spring clip.

Patent No. 5,347,186 is stamped on it, but that number refers simply to a Liner Motion Electric Power Generator so I can't give you a manufacturer name.

This light runs EITHER on batteries or on shake charge. If I shake it up good, the shake light lasts for a few minutes, and a few seconds of shaking thereafter keeps it going.

It contains two wafer batteries, and I have no idea how long they'll last.

The switch is a push-button three-state. On (with batteries), On (with shake) and Off.

The bulb is a single LED with a magnifying lens.

All-in-all, it provides me with enough light at night using the shake mode, and the battery mode is more than sufficient to read by - at least until the batteries poop out.

I have seen "shake only" lights that don't seem to work very well. So the real answer is that some shake lights are a joke and some are not. Buyer Beware.

I have a great "shake" flashlight. It has two large copper coils, I believe a big capacitor and some electronics and it holds a charge for months. When shaken for two minutes you have power for quite awhile, I've never tested it for maximum time. It's called "New Deluxe Forever Flashlight." I believe the company was "itouchless.com" It cost me about $20.00. I've had it since April and have used it quite a bit. Of course, it's not equivalent to the power of a battery operated light, but it's fine for in the house or yard. Just think what one of these would be worth if no batteries could be obtained!

I have 3 shake lights in various sizes. I have one that will hold a charge for days. I don't know the brand. I have a small one that I keep in my EDC that I have to charge everytime I need it but I think that it gets rolled around in my bookbag and the light gets turned on. I have a larger light that I carry in my truck and I am not as pleased with it. It will hold a charge but the light is not so bright. Maybe I just need to charge it longer. If one of these does discharge completely it has to be shaken for about 3 minutes. Not so good if you need light ASAP. Except for this little problem I think they are great to have around for emergencies.

Decided to pick up one of the cheap shake lights. Looked over good to see if it was broken etc. worked good. Son dropped it on concrete and broke it. On other hand, my son got me a brinkman led flashlight. Little large but it is the first LED Spotlight I have seen.

I have bought several types of shake lights for my kids and found them to be pretty darn good. Bright enough to get around in the dark and rumage through your pack. Mine have all held charges for months. In fact, I haven't had one go out on me or my kids yet.

The kids have their play ones, which they use periodically, and shake all the time. I got tired of constantly replacing batteries in flashlights that they left on.

Also, I order a bunch of these for our 4H group as I built their little back packs up:



They are cheap (under $3 per) and seem to last pretty long. They are bright and hold a charge. I wanted shake lights, in addition to the fauxtons attached to their packs, to give the kids something to do if they get lost in addition to signalling.

I wish I had seen those $3 ones before I spent $20 for a set of two of the "as seen on TV" lights.

The large one is supposed to be waterproof and can't be taken apart, but the small one's bezel can be unscrewed and the guts come out. My toddler son did this three times and I was miraculously able to find all the parts each time before I finally glued the whole thing together permanently.

Before I did that, I took a look at what makes it tick. The two wires from the coil connect to a bridge rectifier, which charges a .1 Farad 5.5v supercapacitor. The LED connects to the cap through a mechanical switch. There is no current-limiting resistor but the cap has significant internal resistance that takes care of that. Very stingy minimalist design. Enough to work, but not very well.

While the electronics could be made better, the real limitation of this device is the magnet & coil generator. It is just very poorly matched to the load and source of power (shaking). The magnet is not perceptibly slowed as it passes through the coil, which means very little power is being generated during each shake. A 50-cent motor from a toy car, coupled to a crank or lever through a gear train makes a far superior generator.

It serves its purpose for keeping a toddler busy until he falls asleep, but it would be very frustrating to use for some critical task in an emergency. It is actually worse than nothing, as someone might depend on one of these instead of buying something much better such as a $1 keychain led light.

I'm solely a consumer of bass pro, not an employee or affiliate in any way.

I have used:
$9.99 38-612-962-11 NO-BATTERY SHAKE FLASHLIGHT 7-1/2''
From www.basspro.com for several years. It has a capacitor and a single LED with reflective mirror. It's made out of ABS plastic.

About 2 minutes of shaking is good for 30 minutes of use. Durable, sufficient light for emergencies. I like it though I keep a real d cell batt flashlight too. It's definitely nice for redundancy though. I was surprised most by how long the light lasts on a minor amount of shaking.