# Emergency light project



## Steelwolf (May 19, 2001)

Someone posted about a light like this. It looks pretty good doesn't it? BUT what a bummer! You have to keep squeezing it, at high speed, for as long as you need the light! The second you let up, the glow dims and dies. Not good.

So... add this and this and 2 LEDs, some solder, a little creativity and voila!






Ok... this post lacks a little because I still can't post pictures of the finished product. I'm working on it. Item 2 was a IC bridge rectifier diode (a small square about 5mm on each side), necessary because the output from the generator part is AC, which is fine for filament globes but terrible for LEDs, and the second item which is that 1.0F 5.5V supersized electrolytic capacitor mentioned in another thread.

I set up the LEDs parallel with the capacitor, separated by a simple switch so that I can switch the LEDs on or off. I also added a Schottky diode (1N5819) on the negative terminal of the bridge rectifier between the capacitor and the rectifier because I didn't want the capacitor to discharge in to the generator coils. Was this necessary? 

I also used 2 Nichia white 5600mcd LEDs in parallel. Soldered them in to an old PR bulb base. Should I have gone with only 1 LED? Would that run brighter or can the capacitor supply enough voltage and current to run both LEDs at the nominal brightness?

I will strive to put photos, test parameters and results up as soon as possible, but I would like your input on whether the Schottky diode was really necessary and thoughts if I should have stuck with only 1 LED instead of using 2.

I've charged up the capacitor. Takes about 1 minute of moderate squeezing to get it up to 5.5V (open circuit). Will post runtime results soon.


----------



## papasan (May 19, 2001)

hmm...do you need the rectifier?...LEDs are diodes, it's not that they don't like AC, they won't let AC pass, as long as the voltage not over their rating it should be fine...

i'm not real sure what happens after the generator passes through the cap, but i would imagine that this process smooths the AC into DC, or do caps pass both ways?...


----------



## Free (May 19, 2001)

I have a squeeze light similar to that one and just put in the 2 led bulb from my turtle light 2 no other modifications. Before the conversion, one squeeze would run the bulb for about 1.5 seconds. Now with the led it runs about 5 seconds on a squeeze.


----------



## Steelwolf (May 19, 2001)

Actually, they don't like reverse voltage. I had a couple of LEDs break down because of that. I wanted to protect the LEDs from that. As another plus point, the bridge rectifier helps convert what would normally have been lost as reverse current in to forward current. I'm not quite sure how much I'm losing because of this component though, since it's kind of hard to run the generator with the cover open.

Electrolytic caps are polar, ie they have a positive and negative side and you have to watch how you put them in. I believe that for ceramic caps, it doesn't matter which way you insert them in to the circuit, but in the same way, the side which is connected to the positive supply terminal will become positive. 

I think that in the case of the electrolytic caps, a reverse current will cause some internal damage if the voltage and currents are too high. For ceramic caps, you wouldn't get anything useful from it if the input is full reverse AC because the charge on the capacitor keeps changing and you lose any charge you may have built up from the previous cycle. So for all intents and purposes, I think the bridge rectifier is unavoidable in this circuit design.

KenBar, if you read this, I believe you took apart a predecessor of the NightStar. Did they use a rectifier circuit? What were the other components in there?

I've been playing with this light for a while. The output is about that of a CMG Infinity if you run it straight off the capacitor. But pumping it the way you would have had to before putting in the modifications, you can get a very bright light that is a little better than the Arc Flashlight. 

BTW, I'm running from the capacitor to the LEDs without a resistor. I believe that is the best way to do it? But between the generator and the capacitor, there is a 10 ohm resistor from the original circuit. I believe it was put there so that a current will be introduced in to the circuit. Since the velocity of the magnets through the windings will determine the output voltage, it is hard to think of a way to determine the optimal resistance to insert, such that a reasonably moderate pumping will produce the required voltage and the maximum amount of current. If anyone has an idea, please let me know. (Voltage has to be within 30% of the capacitor voltage of 5.5V for charging to take place.)

Thanks for any further input. Papasan, thanks for enquiring.


----------



## X-CalBR8 (May 19, 2001)

This is one of the neatest projects that I've seen on the board so far. I've got one of the Russian flashlights ordered that I want to do the same sort of mod on and I'm trying to glean as much useful information as I can before I start in on it (so that I don't ruin anything, hopefully). Concerning the memory capacitors, I saw what I believe to be the same capacitor for only $4.00 at Jameco. http://www.jameco.com/cgi-bin/ncommerce3/ExecMacro/Jameco/home.d2w/report?cgrfnbr=657&ctgys=503;516;657; At that price, you could add almost 3 for the price of one of the others that was listed earlier. How big are these memory capacitors? Has anyone got theirs in yet? How many do you guys think could reasonable be fit in one of these hand powered lights. How many do you guys think would be prudent to try to put in one? I know if you go overboard and put in too many, it would take a long time to ever fully charge them. How much power do one of those generators put out when cranked at full speed? Has anyone measured the output on one yet? Also, if the voltage is only 5.5 volts, shouldn't you use a step-up if you are going to use a 2 LED bulb, or perhaps a better solution, why not just use a resistor and a single LED bulb? Which would be the better way to go? Wouldn't the resister idea lead to more useful light with less hand pumping? I can't wait till my Russian flashlight comes in so that I can join in on the fun. Just imagine, with this sort of setup, we should be able to build the ultimate emergency flashlight that will never need batteries and that you could store for a lifetime! I'm very excited about this project because this sort of thing has been a life long dream of mine. Am I a true flashaholic or what? Hehe.


----------



## Free (May 19, 2001)

Wouldn't you have to do the same amount of cranking whether you have a capacitor or just do what I did? 

Each time I crank I get instant bright light that lasts for 3-5 seconds and then I crank again. It seems to me that if you are using a capacitor that allows the light to run, say, a minute... you would have to crank the thing 12 times to charge up for that minute run. 

I wonder how much useable light you would get during the initial cranking time. You would be trading instant light for longer light when not cranking but would still end up cranking the same amount?

Am I missing something here??


----------



## Free (May 19, 2001)

Steelwolf,
How many times do you crank it in a minute to get it fully charged? Also, how many cranks or how long before you begin to get useable light? Is the 3 minute run time useable light or until the bulb quits?

I am curious if 1 Led makes s significant difference in run time, it didn't in mine.


----------



## X-CalBR8 (May 19, 2001)

Steelwolf: Well, looks like you were right about the NightStar being just about the ultimate emergency flashlight. It does seem to me that it could have (and should have) been built much more compact though. For those that would like to check it out, the URL is: http://www.innovativetech.org/ I just spent the last hour reading everything on their web site and from the looks of it, it would be very hard to build a better emergency flashlight, but on the bright side, our flashlights that we are building will cost only about half as much to build. Still, just as soon as I can afford to get one, I would be very interested in purchasing a NightStar to play around with.


----------



## e=mc² (May 19, 2001)

Where is everyone getting their Russian Dynamo Flashlights from in the States?
I've conducted a quick Google search and came up with these two sites which have the light for approx $11 USD. Is this a good deal?
http://www.preparedness.com/dynpumflas.html 
and http://adidam.com/gateway/emporium/health/7086_26299_26345.htm 

Regards, Ed


----------



## X-CalBR8 (May 19, 2001)

Edwood: I got mine from http://www.lighthings.com/ Just do a search for Russian and you will find the page. I paid $9.95 + $4.00 shipping for mine. Also I noticed that All Electronics has them for $9.95. http://www.allelectronics.com/index.html IMO, this seems to be the toughest, best constructed, dynamo flashlight for the money. I only hope that I (along with everyone's help) can do a good capacitor/LED mod on it. Did I happen to mention how excited I am about this project? Hehe.


----------



## X-CalBR8 (May 19, 2001)

Quick question. If you were going to use the 5.5-volt memory capacitor and a single LED LEDCORP bulb that is designed to run in a 4 cell light (6 volts), would you need to use a resistor at all? I guess a better question is this, when you are cranking the light, does the voltage ever go high enough over 6 volts to damage the LED, or is the voltage limited by the 5.5 volt capacitor and will never go over 5.5volts? Will the 5.5volt capacitor act as sort of a voltage limiter in the circuit or not?


----------



## Brock (May 19, 2001)

You should be set with a 4 cell LED. Since the load is so small if you run the 4 cell LED the voltage is around 6.4v. So 5.5 should be fine.

Brock


----------



## X-CalBR8 (May 20, 2001)

Free: The reason for the capacitors is so that if you have to run the light for an extended time, like for example an hour, you won't have to crank every few seconds for the whole time. This would have many advantages besides just a lack of aggravation. Any situation that you need to do something with both hands, such as changing a tire, reading a book, or putting up a tent, you will need a way of storing a charge so that you won't have to constantly crank the light every few seconds.


----------



## Free (May 20, 2001)

I understand the concept. I am just not sure how much cranking it will take to charge the capacitor and have useable light. I am very interested to see if this is going to work though.


----------



## Steelwolf (May 20, 2001)

Since I seem to be the only one who has completed the project and have a running model, let's see if I can answer all the questions and hopefully someone can come up with a improved "mod2".

Firstly, to X-CalBR8:
The capacitor I have is probably similar to the one you referred to. This one is an electrolytic type made by Elna. It is a cylindrical shaped object with a diameter of 21.5mm and a height of 8mm. The legs are about 6mm long and 5mm apart. It is quite small, but I still could not find sufficient clear space to put the capacitor inside the body. It sits outside with 2 holes drilled in to the flashlight body to allow the connections through. BTW, your website quotes it in US dollars, the one I referenced is quoted in Aussie dollars. (Even then, your's is a little cheaper before GST and shipping.)

You would probably be better off using only one capacitor, but 2 in parallel sounds interesting. I'm using only one and it already takes a minute of hard squeezing to get it properly charged up to full capacity. But why I say the 2 in parallel set up might be better is because of the lower resistance of the capacitors when arranged this way. Also, it is easy to charge the capacitor up halfway, but seems to require more effort as the charge reaches capacity, and then seems to lose it faster when the charge is near full capacity. So by having 2 in parallel, you might find it easier to charge and achieve longer runtimes for less effort.

I put in 2 LEDs because I figured that the capacitor should be able to supply the needed current and all that would suffer would be the run time. The intensity should be about 1.5x of using only 1 LED. Will tell you more about it when I build the 1 LED bulb. The only advantage I can find with using 2 LEDs is only when you are actively pumping the charging handle while the LEDs are running. It gets very bright. Not like the Arc as I stated earlier but closer to the PLW3. With a single LED, the runtime should approach that of the Nightstar (5min), but you lose out because it wouldn't be as bright when you pump the light while it is in operation. In both cases, I really don't think a resistor is needed, but I could be wrong. Hope Craige or Gransee jumps in soon.

As for the generator out put, I can't measure the raw output because that is in high frequency AC and my multimeter can't seem to get a good reading. Probably need a osciloscope for this. Besides, it is really hard to run the generator with the body open. Will try again, plus the post-rectifier voltage. Current is out of the question because everything has been soldered together.

As to the ultimate emergency flashlight, I think the NightStar is as good as it gets. The handcranked flashlight is not waterproof in the slightest, feels cheap in the hand and might break quite easily, and requires quite hard pumping which will increase the chances of something breaking or cracking. But for me, I think it's cheaper. About AU$35 for all the components (flashlight, Schottky diode, bridge rectifier, capacitor, LEDs, solder, wires and glue) compared to AU$120 for the NightStar.

KenBar, I would like to find out how the emergency light performs with the 9V step up. Do post and let us know. About the NightStar, I understand why you would not want to talk too much about it. But please just nod if I'm on the right track with the bridge rectifier. I sort of figure that it is needed because the output from the NightStar's generator would also be AC. And I really wish I knew if that Schottky diode was really needed.

BTW KenBar, did you get the pictures I sent? Were they clear enough? I got to get me one of them close-up lenses real soon.

The run time of the light I built is about 3min before it gets a little too dim to be useful. But it actually glows for a very long time. The advantage of the squeeze type generator over the shaking generator (a la NightStar) is that you can pump up the power even as you use the light. And it does get very bright. Almost like the PLW3 that I have. But having the 2 LEDs has probably reduced the run time quite a bit. I'll probably buy a few more cheap PR globes and replace it with a single LED and see how long that runs. And I keep wondering about that Schottky diode (I'm starting to repeat myself, so you know it is really bugging me.)

Happy experimenting guys, and don't hold back those thoughts and questions. I will try to answer if I can.


----------



## X-CalBR8 (May 20, 2001)

But will the 5.5-volt capacitor act as a voltage limiter? Or what about when the capacitor reaches it's full charge, will it ever allow more than 5.5 volts to travel through it when you are actively cranking the light?


----------



## X-CalBR8 (May 20, 2001)

Steelwolf: Thanks for taking the time to give us such a long and informative post. I'm anxious to get every little detail that I can so that I can gain a better understanding of exactly what is going on in the circuit. About the 13 volts that you mentioned, did that occur before the capacitor or after it? 13 volts would blow a single LED, for sure, is why I ask. I believe you are definitely right about 2 capacitors being better than 1 for various reasons. I think that is what I'm going to try on my mod just as soon as I get my Russian flashlight in. It should be in tomorrow, I hope. I wonder if Radio Shack carries the 5.5 volt memory capacitor. If they did, it would save me from having to order them and wait days to get them in. I'm also anxious to hear from someone that has taken voltage readings from the Russian flashlight to see if they are the same as the other hand cranked flashlights that have been tested. Has anyone got theirs in yet?


----------



## Steelwolf (May 20, 2001)

The 13V is after the capacitor. This was measured across the contacts for the bulb. The LEDs are not any the worse for it. I really doubt if the capacitor dumps 13V across the LEDs. This is more likely to be a reflection on the charge available rather than the actual output voltage. I have tried running the LEDs while handcranking like mad, and plugging in the LEDs immediately after measuring the 13V. In both cases, the LEDs survived and there was no noticeable damage. BTW, my setup is 2 LEDs in parallel. Haven't tried single LED.


----------



## X-CalBR8 (May 20, 2001)

Hmm… That is strange that a 5.5 volt capacitor could allow 13 volts to exit it. That is just such a large voltage difference. I wonder if this is the effect of the capacitor or the result of the large peak voltage that is produced by the light when cranking at very fast speeds. I suppose that proves that the capacitor does not act as a voltage limiter if it allows that large of a voltage to exit it. Didn't you say that you had also included a rectifier circuit before the capacitor? It seems as though it should have a cut off point of the amount of voltage it would allow to exit it also. Have you tested the voltage entering the capacitor to see what the peak voltage is there? It would be interesting to know if it goes over 13 volts at that point. Also, does the voltage exiting the capacitor only hit 13 volts after the capacitor is fully charged or before? What troubles me is this: If the high voltage peak is a result of the capacitor, then the effect could be doubled when trying to use 2 capacitors. Also, the reverse might be true. 2 Capacitors could act to smooth the voltage out and keep it from spiking when cranked vigorously. It would probably take some experimentation to find out which theory is the correct one. Wouldn't it be possible to build a voltage clamping (or even a voltage smoothing) circuit at the capacitor exit to keep the voltage from spiking above 6 volts and keep the LEDs from receiving a deadly surge? I'm very surprised that you haven't had a blown LED, even though you are using a 2 LED bulb instead of 1, with that large of a surge.


----------



## Steelwolf (May 21, 2001)

More answers to your questions.



Hasn't anyone else built theirs?





Free: You probably have to do a heck of a lot more cranking. One minute of moderate cranking will give you about 3min of light at the intensity of a CMG Infinity. Or you can really open all stops and crank like a maniac. That gives you a brilliant light that dims in about 30sec to the Infinity level. The light seems dim, but in darkness, is quite usable for a long time. The capacitor discharges very quickly at the start but reduces its output to a more sustainable level and provides a long run time. Also, because the capacitor output reduces as time passes, the LEDs actually don't go out for a long, long time. They just keep glowing. 

I think that because of the character of the capacitor, it might actually make sense to use 2 in parallel. The charge is more stable but the available current is higher and you don't have to crank it as hard to achieve a stable charge. What do I mean by stable charge? If I were to crank like a maniac on steriods and speed, I can actually bump the open circuit voltage all the way to around 13V. Of course this is very unstable and the capacitor quickly loses its charge. It seems happy to stay around the 3-4V range forever, not quite at the 5.5V advertised. I believe that 2 capacitors in parallel would give us brighter LEDs for a slightly longer runtime with less maniac cranking required.

Of course, all these are open voltage values. I believe the capacitor acts as a sort of voltage limiter. I managed to hook up my multimeter while I was cranking like a madman, but only got about 6V. When the rotor stopped spinning, the reading jumped to about 13V. Managed to repeat this result several times. I'm going to try and hook up the multimeter so that I can measure the output voltage from the rectifier for different rates of cranking.

BTW, I refer to moderate cranking as about 2 cranks a second. But that only tells half the story because if you pump hard, you can accelerate the generator to a higher speed in between each crank. It has to run quite fast because you need to achieve approximately 5V to charge the capacitor. But this is no worse than trying to run the original bulb at a yellow glow.

Hope I managed to answer all the questions clearly.


----------



## Steelwolf (May 21, 2001)

I'm afraid that there is not much more I can tell you from this project. I was in such haste that I completed building it before I had tested all the parameters. Now the bridge rectifier and capacitor are all below the gear wheels, so it is nearly impossible to do run time measurements while handcranking the thing.

I do intend to build a few more for friends and family, so I will soon have parts for "Mk II". I will remember not to install everything until I have full run time data.






BTW, I have been cranking like mad again, but I can't seem to get it above 7V this time. Maybe I'm just tired. My own understading is that a capacitor stores charge. The potential difference, or voltage, across two points is also a reflection of the stored charge. The difference between a capacitor and a battery is that a battery stores the charge as a chemical change while the capacitor stores it as electrical charge, ie a difference of the number of free electrons on one plate as compared to the other. This will probably manifest itself as a voltage difference, though when the power is demanded, it will not be able to deliver the entire voltage it shows (especially in these large capacity electrolytic capacitors). That, anyway, is my thoughts on the matter. I wish someone who knows these things better will come and help clarify why we are seeing these parameters.


----------



## **DONOTDELETE** (May 21, 2001)

Hi Steelwolf!

As far as I understand capcitors, there are some different types, but you could divide them in two major categories:

1. "Real" capacitors, which build an electrical field between two metal plates and a dielectricum between them. The classic plate capacitor which consists of two large metal plates with an air gap between them is the simplest. Electrons gather at one side of the cap, and are missing on the other. The charge in this cap is pure ELECTROSTATIC.

If you change the dielectricum from air to special polymers, caps can be built smaller. Examples are all the foil capacitors like MKT, MKS, MKP, ceramic, Styroflex, which all are named after their dielectricum.
These kind of capacitor has no preferred polarity and can be charged in both directions. Also they cannot leak. The only thing that can happen if the rated voltage is exceeded, is that there is a charge breakthrough. If this happens, a small defect results, which doesnt affect further fuction much, if the cap is a so called "self-healing" type.

The second category of caps are the Electrolyte Capacitors. They dont store electricity in a real electrostatic way. The electrolyte stores electrical charge in a way like a battery or accumulator, but can deliver it much more faster than a battery. Also it can be "recharged" almost infinite times. But the charge is not as fast available as in a electrostatic capacitor.
The advantage of the electrolyte capacitors is their increase capacity at smaller package size. Just compare a 1yF MKT cap with a 100 yF electrolyte cap of the same voltage...
But elec.caps. have the disadvatage of being polarized, so they can be charged in only one direction (try charging one in the opposite direction on sylvester!!!), which makes them unuseable in some applications. There is one exception, some special elec.caps. are bipolar (this is why they are called "bipolar capacitors...), which are mainly used in 2 or three way pathways for audio speakers as a highpass-filter.

The super-high-capacity elec.caps (the first brand has been "Gold-Caps") have a special electrolyte. The disadvantage is their low maximum voltage of 3 or 5.5V. But they should be understood as a bridge between eletrolyte caps and accumulators. They can be rechared infinite times, but can store much more charge than a usual elec.cap (perhaps you know the 1F elec.caps used by car-audio-enthusiasts to stabilize the 12V just before their high-power-car-amps, these monsters are almost a foot in length and 1/4 foot in diameter...). A 1F Gold cap is much smaller (and much cheaper...).

These Gold-Caps are available in sizes of many Farad (up to 220, as far as I know) and can make a replacement for accumulators in some applications (I know there are some slow-flying RC model aircrafts, which use these instad of NiCd cells).
Also there are experiments to reduce the large lead acid battery in cars to a real small one with adding a Gold cap (of really MANY Farads) in parallel. The battery in a car has to be of a specific size to deliver the hundreds of amperes when starting the car. When the car is driving, the battery has only to deliver a few amps. So the small moments of high current are delivered by the Gold cap, which reduces the battery size dramatically (which is very good for the environment



).

Ok, ok, I came a little bit off-topic...

Back to your problem:

I would recommend to not overcharge a Gold-Cap, as this destroys is very fast!
Just put a Z-Diode of 5.1V parallel to the cap limiting the voltage...

Bye!


----------



## X-CalBR8 (May 21, 2001)

Phantomas2002: Thanks for the tip about the Zenor Diode in parallel with the capacitor. That should save the LED from getting a deadly voltage, I hope. I very much enjoyed reading all the info on capacitors. I learned a lot and remembered a lot that I used to know but had since forgotten. As for getting a little off topic, I don't mind at all. The way I see it, even if I don't use the information that I learn on the current project that I'm working on, all knowledge is useful, and it will come in handy to know for use in a future project. So please feel free to share any information that could be of use to us fellow inventors and flashaholics. It is much appreciated.


----------



## Free (May 21, 2001)

I have a Nightstar and I don't think you would want to take it diving with you. For one thing, it is not very bright out of water but underwater....forget it. Also you would have to be Hercules to shake it enough to charge it underwater!!

Have you guys seen this yet? It has a LED light and it says that just a few squeezes gives several minutes of light!! It will also charge a cell phone battery. 2 minutes of squeezing for 20 minutes of talk time. I think I may order one of these.

Aladdin Hand Powered Generator


----------



## Free (May 21, 2001)

Here is some more information. It looks like they are also working on a step-charger that will supply much more power!!

StepCharger


<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>To ensure proper recharge voltage at all times each STEPCHARGER and ALADDINPOWER hand operated generator is supplied with an Elepool specially designed electrical circuit regulator which is able to amass generated electricity and regulate the proper amount to the device being recharged (example: cellular telephone). <HR></BLOCKQUOTE>

Aladdin information

Aladdin Home Page


----------



## X-CalBR8 (May 21, 2001)

Free: Yeah, I thought about purchasing one of those a while back, but from all of the pictures that I've seen of it, it looks like it's made of cheap plastic. I also read on one page that was selling it that it's life expectancy was only about 1 year, and the warranty is only for one year, so it seems to add up. If they had a version that the gears were made of metal instead of cheap plastic, then I would have already bought one. I still would like to hear from someone that has actually purchased one to see if it feels as cheap quality in the hand as the pictures make it look. Also, in all that I've read about it, it never mentions whether it uses a capacitor or NiCad/NiMh batteries to hold it's charge. I'm assuming it uses a capacitor, but it never explicitly says so in anything that I've read so far. If it doesn't use a capacitor then it would be worthless in an emergency kit because in a matter of time the batteries would go bad and leak. I would like to know a little more about the Aladdin though if anyone has had any first-hand experience with it.


----------



## X-CalBR8 (May 22, 2001)

Check out this link for the cheapest price on a NightStar that I've found so far. http://www.shakelight.com/ It's still pricey at a hefty $59.00, but it's still $10.00 cheaper than at the NightStar homepage! Even though I'm going to enjoy modding my Russian flashlight when it comes in, this is still one flashlight that I would like to add to my collection eventually. I've not seen a more indestructible, battery free, reliable, waterproof to diving depths, easy to use magnetic switch, flashlight ever. This is the first and only flashlight that I've yet seen that I truly believe could be kept in storage and be dependable for a lifetime. Thanks Steelwolf for putting me onto it.


----------



## X-CalBR8 (May 22, 2001)

Big news! NightStar is having a Father's Day Sale and the NightStar will be priced at $49.00 until June 17th. http://www.nightstar1.com/ This flashlight usually runs about $60.00-$80.00 so this is a great deal. If you've been thinking about getting one of these cool flashlights, now would be the best time ever. Now I just need to scrape up enough cash before the deadline.


----------



## Steelwolf (May 22, 2001)

X-Cal, the link doesn't work. Perhaps you meant the Innovative Technologies website?

Something wrong though. Can't seem to get to order page. BTW, do you have any idea where you go if you take out that 1 behind and type in www.nightstar.com? Looks like some sort of male high libido orientated site. I didn't bother to go further because I'm in my uni computer lab and the front page was embarrassing enough.


----------



## X-CalBR8 (May 22, 2001)

Steelwolf: Yeah, they have like 3 or 4 mirror sites (I just listed one), and yeah, they seem to have some kind of link to some sex oriented site on all of their pages. I'm not sure what the whole sex thing is all about because once I saw that they had dropped the price of the NightStar to $49.00 that had my full attention. I think they are trying to sell some product that is sexual in nature or something like that on that other link. My big question now is has anyone got a NightStar already and is it worth the high price? Is it overly aggravating to use, and how much useful bright light do you get before you have to shake it again? The web site claims that it will give 5 minutes of light with 30 seconds of shaking, but is that 5mins of useful light or just till it goes completely dead?


----------



## Steelwolf (May 22, 2001)

I have one of those. Beautifully built. The LED is not particularly bright. Just about the level of a CMG Infinity, but because of the lens, the beam projects far. Non-stringent runtime tests actually put the run time for usable light at about 3min. But it just about glows forever. I'll try again tonight. 

As KenBar said, it is really an emergency light for when there is nothing else brighter, because it really only becomes useful after you have been dark adapted. And there are all manner of problems with having those bloody powerful magnets. Your floppys get wiped, your TV and computer screens get a weird hue (they need to be degaussed after their close encounter, or you can leave it and wait for it to return to normal which takes about 3 weeks of use).

Perhaps a better light to look at is the Freeplay range of lights, and particularly the Freeplay 2020. This has LEDs for long runtime, a xenon bulb for when you need projection and a handcrank operating a coil spring for emergency lighting. I'm not sure, but I think it has a solar panel as well.

I have the S360 radio, and so far, all I have is praise for it. The solar panel recharges quickly, the spring powered generator runs well and quietly. You can quickly crank it up and it will provide so much run time that the generator system of the Nightstar looks pathetic in comparision. And the magnets used in the generator are *not* so powerful that metallic objects start getting a hard on for it. Only trouble is the spring is rated for so many cycles and it uses NiCd batteries. So in about a year, you might have to replace batteries, in about 5 years you might have to have the spring replaced.


----------



## X-CalBR8 (May 23, 2001)

Yeah, those are the problems associated with almost all emergency lights that are commercially available. The weaknesses that I see that must be overcome in order to build a truly reliable emergency flashlight that will last a lifetime are as follows: 

A reliance on rechargeable batteries (NiCad/NiMh) that go bad in 1-3 years instead of a large capacitor array that can do about the same thing and last for well over a lifetime. Not only can the batteries just go bad, but in the process, those batteries can leak in an emergency kit and destroy other things besides just the flashlight that contains them. It's all about cost. They had rather make something cheap that will last a few years than to use capacitors, which are much more expensive, and make something that will last for more than a lifetime. It all goes back to this being a disposable minded society that we live in… 

A spring loaded system that becomes totally useless after a few years because, no matter how well made, a spring will always loose its spring in a matter of time. The more you use the device the quicker this will happen, but it will also happen by just sitting in storage also. I've had the mainspring on watches do this simply by storing them for a few years. Just ask anyone that repairs watches and clocks, what is the main thing they have to replace, and they will all tell you that it is the main spring. People may say "I have a watch or clock that is 100 years old and still works," but just ask them how many times the main spring has had to be replaced in that amount of time. 

Often times there is a reliance on solar panels that deteriorate over a period of years. At least this has always been my personal experience with them (usually in less than 10 years for me). This is not to say that modern solar panels have not conquered this weakness. In fact it is very possible that they may have fixed this weakness in more modern solar panels, but I just have not found any of them that would last a lifetime for me yet. 

Using components that are affected by hot or cold that renders any such emergency flashlight completely useless for use in a car or other extreme temperature condition. 

A lack of a moisture seal to protect the internal components from moisture damage over time, or better yet, design the flashlight to be completely waterproof. If you live in a high humidity environment like I do, or just store your emergency equipment in a place such as a fall-out shelter or basement, then this becomes an even larger concern.

Using any components that aren't rated to last a lifetime. Most companies will try to use cheap quality components in order to turn out a competitively priced product. Anyone building a truly reliable emergency flashlight would have to take into account such things as the rated lifetime of all components used. If even one component fails, it will render the entire device useless.

The use of too many moving components that can easily fail. This is the biggest weakness that I've found in the hand powered flashlights such as the Russian flashlight (Forever Light). If even one gear fails, then there goes the usefulness of the entire flashlight. This weakness can be strengthened greatly by the use of all metal gears, but still it is just a matter of time and use before the unit will fail due to a failed gear.

And of course one of the most obvious weaknesses, that I'm sure almost anyone on this forum would be quick to recognize, in many emergency flashlights, is the use of old fashioned bulbs instead of using LED bulbs that almost never fail. 

This list may not bring attention to all of the weaknesses associated with most current emergency flashlights, but having a clear idea of most of the problems is the first step toward overcoming them. In designing our own mods, and other flashlight inventions, we can take all these things into account and come that much closer to designing the ultimate emergency flashlight that will last a lifetime.


----------



## Steelwolf (May 23, 2001)

Just with regard to the solar cells, I have a bunch that were built by Siemens over 10 years ago. They were put in to garden lamps and sold as a complete package. Now, after so many years of abuse, baked in the sun, drenched in the rain, having all manner of insects, lizards, spiders and other garden creatures build nests in them, the only part of the light that still works is the solar cell. I've had to replace the rechargeable batteries twice and the bulbs a half dozen times. (Those models that used a fluorescent tube have not needed to have the tube replaced.) Everything else is now rusted or corroded and all I have of these lights are the plastic bodies, the cells and a mass of corroded circuitry (but some of the individual components are still working.)

The cells were covered with a sort of clear silicone on one side and by the plastic frame on the other. Amazingly, the silicone has not discoloured and the cells still work.

My own thesis project has demanded that I read practically everything the library had on solar cells and as far as I can tell, it is not the silicon wafers (might not be silicon anymore, since I read that they were trying stuff like GaN) that go bad. It is the faint spiderweb of wiring on top of the cell that corrodes and junks the whole thing. I'm not sure if the wires are user replaceable, but at the very least, it suggests that the better the encapsulation, the longer the cell will survive.

Mine have survived over 10 years with no apparent deterioration.


----------



## hank (May 23, 2001)

Here's the Aladdin hand charger on sale, at http://www.igo.com 

Alladin Power Hand Charger Charger 
WAS: $69.99
SALE: $19.99 Item #: 64994 

It's the charger unit, which indeed feels like cheap plastic, seemed like I felt a gear slip a couple of times when cranking it;
-- a module called an "elepool" (voltage regulation of some kind, not explained; intended to protect a cellphone battery, with a little red LED that is said to flicker when the battery's up to capacity; says something about changing the frequency of the output, not very clear; maybe a capacitor?); 
-- and a LED light (light is a LED light making a blue center, yellow ring). 

Cranking it with the light alone plugged in you get a light that brightens fast and fades fast. With the "elepool" module in place the blue LED light brightens up more steadily; it really flares bright while the cranking's being done then fades a bit; it's only an emergency-flashlight level. 

Here's why y'all might want to try this -- I hope someone with some electronics expertise takes a look. After using the charger til the LED light is about as bright as it gets, you can take the two modules ("elepool" and light) off the charger, and the light stays usable for several minutes and keeps a little glow for a long while.

The LED is inside a little plastic module with a coaxial power plug, and the LED is underneath a clear plastic bubble that has a lens molded into it to focus the light into a fairly tight beam.

I'd guess the "elepool" is just a capacitor to smooth out the generator output -- haven't a clue how to check. Anyone got an X-ray machine? If it were a real voltage regulating circuit that'd be nice ....

I never got the iGo.com site to accept an order so I used the telephone order number, and they gave me a little discount because the web page had failed. Nice folks, tho' most of the stuff on their page is priced for business travelers. 

I'd imagine there are not too many more of these gadgets in their closeout so if this posting has aged, don't count on it.


----------



## X-CalBR8 (May 23, 2001)

Steelwolf: It is good to know that they are building more reliable solar cells these days. I'm just curious if they have any that are advertised to last a lifetime yet. Solar cells recharging an array of memory capacitors would be a very interesting project to try. No NiCad/NiMh batteries to go bad over time. The capacitor used in the NightStar is advertised to hold a charge for over a month, I believe. That is about as good as you could hope for in a rechargeable battery anyway. I think I have a new project to experiment on sometime soon.


----------



## Steelwolf (May 24, 2001)

These days? Those cells were built over 10 years ago.



I'm going to try that memory capacitor as a battery sort of thing. If it holds a charge for a month, that is actually better than NiMH and I think NiCd as well. I think I read that after a month, there would be less than 30% charge in the batteries and they can actually lose as much as 5% each day.

But can anyone say how many 1 Farad caps you need to approximate a 650mAh battery? I can't seem to make any reasonable conversion.


----------



## Free (May 24, 2001)

Hank, thanks for the link, that is a much better price, I ordered one. It will be interesting to play with and nice to have for emergency cell phone charging.


----------



## php_44 (May 25, 2001)

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR> But can anyone say how many 1 Farad caps you need to approximate a 650mAh battery? I can't seem to make any reasonable conversion. <HR></BLOCKQUOTE>

Just one caveat here:

A capacitor stores electrical charge, rather than generating electrical energy from a chemical reaction. So when you put a constant current drain on a capacitor, the voltage across it will linearly drop to zero over time. On the other hand, the chemical reactions in a battery will try to hold the battery voltage constant during discharge until the chemicals are nearly exhausted - then the voltage will start to droop.

So we'll treat a capacitor like a battery and say that we'll consider it discharged after it's voltage droops to 2/3 of what we charged it to.

Someone reminded me that a current of 1Amp will cause a rate of change of 1V/second in a 1 farad capacitor. So for a *100mAH* 4.5V battery (that we'd discharge to 3V), you'd need a capacitor of:

```

```

So you'd have to buy *70* or so 3.3Farad capacitors to match the energy in a 100mAH 4.5V battery assuming you'd drain both to 3Volts.

Makes ya appreciate chemical energy!


----------



## X-CalBR8 (May 25, 2001)

I just thought of another advantage of using capacitors instead of rechargeable batteries. Capacitors can be charged from house current (or car battery) almost instantly whereas rechargeable batteries would take hours to charge. Of course, with solar panels, it is going to take a while to recharge either one. Has anyone checked to see what the capacity of one of those monstrous car audio capacitors is? Imagine building a LED light with one of those hulking capacitors as the power source! We should check into the feasibility of this idea. I'm pretty sure that www.crutchfield.com carries these. I need to see if I can find us some specs for them.


----------



## X-CalBR8 (May 25, 2001)

Here is the link for the car audio capacitors at Crutchfield. There is something that I don't understand here though. These capacitors are huge monsters and they only rate at like 1.0-1.5 Farad. What am I missing? There has got to be much more capacity in these huge things than the tiny little memory capacitors that we were looking at before. Any ideas?


----------



## Steelwolf (May 25, 2001)

Crutchfield has some pretty big capacitors with 16V and 20V output. But the price! $299 for one of them. I think their size has to do with the extra electronics inside. Charge indicator LEDs, wrong polarity warning LED,... anything else? 

Try RS Components. They have huge capacitors too. And these are just plain caps, no fancy electronics inside, so the price is a little lower. And that was where I found the 500V 3300uF cap. They also have stuff around the 20V region. Look under Aluminium Electrolytic Capacitors. There is one which is 16V 470,000uF. That pops out roughly 60 Joules of energy. Can we use that?

Downside: the specs show that there *is* a finite life to these monsters. As much as 20,000 hours for some as little as 9,000 hours for others. Don't know exactly how they count those hours though.

BTW, it appears that only the Alumium Electrolytic Capacitors have the high capacitance that we are looking for. All the others (polyester, polystyrene, ceramic, tantalum) have much tinier capacitance.


----------



## X-CalBR8 (May 25, 2001)

Steelwolf: Yeah, if we start using capacitors with a limited lifetime then it would really defeat the main advantage to capacitors that we were looking for in the first place, which is, an almost indefinite lifetime of use, unlike rechargeable batteries which go bad in 1-3 years. I'm not sure what the actual amount of power would work out to, but if one of the 5.5 volt memory capacitors would run a LED for 5 minutes, then an array of 12 of them, charged with solar energy, would run the LED for an hour. This seems to be a practical number to me. At $4.00 a pop, 12 memory caps would only run $48.00 total. Then all you would need is a solar panel, LED, and perhaps some sort of voltage regulator circuit. Even if you get really fancy with the circuitry, the total cost for this project should still stay under $100.00 total and you would have the ultimate emergency LED light in the world. The big advantages of this design would be, if done correctly, this LED emergency light would have the potential to last a lifetime and never need a battery, ever!


----------



## Steelwolf (May 25, 2001)

X-CalBR8:



You have the clearest thinking head here I think. I was working out how many capacitors I would need for one hour of use using my energy equations and came up with 123 if the current is 30mA and 17 if the current is 20mA. But you had the simplest and easiest way to figure that out.

I think that if the charge were kept slightly below the full capacity, the life of the caps would be greatly extended. Certainly, as it is, I'm sure these caps will last far longer than NiCd batteries. I think the reason why lifespans were given is either because the electrolyte the caps use has lifespan before it starts to decompose, like a shelf life, or a charge/discharge life like a battery (the nature of the chemical used for the electrolyte changes), or it might start to dry up after a while.


----------



## Steelwolf (May 26, 2001)

hehehe



I dug out my old textbook and did some simple calculations to get a ballpark figure. I equated everything in terms of joules. For a capacitor the equation is:

Work = 0.5*Capacitance*Voltage^2

For the 5.5V 1F capacitors, that would be about 15.125 Joules.

I then took a 3.6V 650mAh battery. 
Work = I*V*3600 (since P=IV give Watts which is really Joules per second)
This gives 8424 Joules.

Which means approximately 557 of those 5.5V 1F capacitors are needed just to store the same amount of energy. There is, of course, the question that php_44 brought to light, and that is whether the capacitors will provide enough useful power when it is 2/3 drained. At the same time, one also asks how much of that 650mAh can be extracted for useful work in a LED flashlight. Does it drain to 1/3 capacity before it becomes unusable?

And using these same formulae, it would appear that the large industrial capacitors have heaps more capacity than these puny memory capacitors. Try 500V 3300uF. It gives 412.5 Joules. This appears correct, especially when you behold one of thes capacitors. It is as big as a D cell. But how would one limit the voltage so that it can power the LED for a long period? Think of a way to limit the voltage without wasting too much power and I think we might have a viable alternative to using batteries. (You only need 20 of these to approximate a 3.6V 650mAh battery)


----------



## Steelwolf (May 26, 2001)

Forgot to add... how do we charge these monsters up? Solar cells, Freeplay type coiled springs, handcranking (we going to have Mr. Universe type arms after all that cranking I think)? 

I think for capacitors, and maybe also for batteries, the charging voltage must be within 30% of the rated voltage of the storage device. So we need an effective step up and step down transformer to use the 500V monsters.


----------



## X-CalBR8 (May 26, 2001)

You are probably closer to the mark with using 17 memory caps. It all depends upon the physical size of them as to how many would be feasible for use in a handheld unit. The way I arrived at 12 was just a simple estimate (and not very scientific) that didn't really take into account how bright the LEDs would burn at for the first hour. Either way, the cost shouldn't be so high that it would prohibit us from building this project. Just think about it, we would have something very cool that nobody else in the entire world has! Just that would justify the cost to me.



I only wish that we could get a life expectancy rating for the memory capacitors that we were planning on using so that we would know for sure. I know that they would last many times longer than rechargeables, but I wonder if they will last as long as the capacitors in the NightStar. If these are the same capacitors used in the NightStar flashlight then they should have close to a 1 million-cycle life. At least that is what is advertised at the NightStar homepage. I've dreamed up what I believe would be the most efficient way to build this project. It just came to me while I was pondering the best way to go about this. Get 2 solar panels that are rectangle in shape and are sealed to keep out moisture, possibly the kind with the honeycomb lenses that would protect the solar panels. Then take a Circuit Board (the kind with holes for mounting components) and cut it the same size, or just a hair smaller, as the solar panels that you will be using to charge the capacitors. Mount the capacitors on both sides of the circuit board along with any voltage regulating circuits that we will need, then sandwich the capacitors/circuit board between the 2 solar panels and glue with hot glue or epoxy (depending on whether you are ready to make it permanent or not). Mount the LED (perhaps with a head assembly) to the top of the sort side of the rectangle assembly with hot glue or epoxy. Then all that is left to do is mount any type of switch that you like to the top of the rectangular assembly. When you get done with the design that I have in mind, it will look something like an Ice Cream sandwich. Perhaps I can draw a picture if this is getting a bit confusing. With this design, no matter which way you lay the flashlight down, it will always have a solar panel facing the light, or if you hang it up, both solar panels could be made to face the light. These capacitors should last a lifetime and keep a charge for over a month, I think. If these memory capacitors have the kind of life expectancy that I believe they have, then we will truly have one of the very best, and most advanced, backup emergency flashlights on the planet! Let me know what you guys think of this design and please help me to figure out what kind of voltage regulator circuits and solar panels would be necessary to make this design work. Together we can do this!


----------



## X-CalBR8 (May 26, 2001)

If we use a single 3.6-volt LED overpowered to maybe say 4 volts, it should be easily powered by a 5.5-volt capacitor array. It should run a single LED for a long while even without a voltage regulator, but with one, you could pull every last bit of juice out of the capacitors until they are completely drained. I'm going to try to find some good solar panels for the project today. I guess the main thing that I need help with now is designing some sort of voltage regulator to charge the batteries from the solar panels and to make sure that every bit of juice is completely drained from the capacitors when running the LED so that the maximum run time can be achieved. Any ideas?


----------



## Steelwolf (May 26, 2001)

I'm not sure it would be such a great idea to use solar cells as the sole charging device. We can only run the LED for a single hour. That means that if we should require a longer run time we need to recharge the caps when there is no sun available. Kinda defeats the purpose for a light. 

I'm still looking at designs for spring driven or handcranked generators to charge the caps. I think this might be the best way to go about it. Then later, add a solar panel and a NiMH or similar battery. The idea is to try and couple the correct energy source to the correct storage size. You can get a lot of sun in one day. More than enough to run a single LED all night. But that's going to be useless if you use caps that can only hold enough juice to run for one hour.

But if you're going ahead with the idea, remember to put a diode between the caps and the solar cells. This is to prevent the caps from discharging in to the solar cells. (remember, they are semiconductors, just like your LED, and will eat power if they are not producing any.)


----------



## X-CalBR8 (May 26, 2001)

The main reason that I decided to make the switch to Solar is that most hand cranked LED lights that I've seen so far require a LOT of work and only produce a very small amount of light for a very short time (about 5mins at most and only the first 30 seconds is really full brightness). The Russian flashlight that I just got in was quite disappointing, especially without doing a LED/capacitor/rectifier (it's AC current) mod yet. The generator only produces a very small amount of power compared to the amount of work involved, and trying to squeeze the handle and see by the light produced at the same time is very disorienting to me. The generator is very unreliable in this type of light also because it depends on a multi-gear system in which only one gear would have to fail and you are in the dark again. I don't think it would take many hours of cranking for this to happen either.

Then there is the NightStar system of generating power that involves a super powerful, and therefor very dangerous, magnet that you can't allow within 16" of almost anything electronic (E.G. Monitors, TV's and Hard or floppy disk). So on account of those issues, there goes the idea of getting a NightStar and doing a Mod on it. So unless a better, safer and more reliable way of producing mechanically powered lights is discovered, the only real viable option left IMHO is to use solar energy. The run time wouldn't be as long as a hand powered light, but believe me, after 1-2 hours of cranking on a mechanically powered light (such as the Russian Forever Light), you would be about ready to call it quits anyway. 

I just happened to think of something else also. If you order in quantities of 10 or more, I think I remember seeing a place to get the memory capacitors for like $3.00 instead of $4.00, which would significantly alter the cost of going the solar route. For instance you could put in 20 memory caps for almost 2 hours of run time for only $60.00 and still keep the total parts cost under $100.00. It all depends on how physically large the memory caps are. I need to look up the dimensions to see about how many could feasibly be used in a reasonable amount of space.

You could always have the secondary source of power for the light to be 2-3 AA's for when the capacitors run out of juice after the first 1-2 hours, or an external hand crank device that you could plug into the main flashlight. Just use simple & cheap headphone jacks to plug it in. The other cool thing about using such a capacitor array is the fact that it can be charged almost instantly from house current, car battery or rechargeable batteries because capacitors charge almost instantly if enough power is available to them. LOL. Just try that with rechargeable batteries that take 1-8 hours to charge.


----------



## X-CalBR8 (May 26, 2001)

I just happened to think of something else to extend the runtime past 1-2 hours. Use a variable resister to get the amount of light needed. You could double the run time with half the light, if needed.


----------



## X-CalBR8 (May 26, 2001)

Hey guys. I just read that NEC makes a 3.3 Farad 5.5 volt memory capacitor. Have any of you heard of that or know where to order one? Those would be very cool to try out.


----------



## X-CalBR8 (May 26, 2001)

Wow! This site tells all about the new so called "Super capacitors" that hold as much of a charge as a rechargeable battery. http://www.chipcenter.com/eexpert/akruger/akruger008.html The only problem is that I've searched for hours and can't seem to find anybody that sells these amazing capacitors. Does anyone know of a place to buy some of these?


----------



## Gransee (May 27, 2001)

Here's the link again:
Cooper Industries

I'm sure they are many other manufacturers.





Peter


----------



## X-CalBR8 (May 27, 2001)

Thanks Peter for the link, but I can't seem to find a place to buy them anywhere.


----------



## X-CalBR8 (May 27, 2001)

I have found all the major parts that I will need to build this project except for the Super Capacitors. I read that some company makes them at 6.3 volts, which would be perfect for this project. The solar panels that I was checking into produce 6 volts and the LEDCORP bulb that I have runs at 6 volts, so now if I could get Capacitors that would operate at 6.3 volts, it would be just about the perfect combination. I guess I will waste another day looking for them before giving up because I *really* want to build this project!


----------



## springnr (May 27, 2001)

Another Dynamo/Solar Radio priced right for converting.


----------



## X-CalBR8 (May 27, 2001)

I just read on the Dynacap homepage that thier super capacitors are rated for over 1 million charge cycles! That is just the sort of thing that I'm looking for in this project. At 1 million charge cycles, the LED is liable to go bad before the capacitor does. LOL. Never thought I would find any power storage device that has the potential to outlive a LED.


----------



## X-CalBR8 (May 27, 2001)

Springnr: Thanks for the link. That would be another excellent candidate to convert to capacitor power. Now I've just got to find some of those super capacitors for sale. This just makes one more thing that I would like to mod with them.


----------



## X-CalBR8 (May 27, 2001)

Thanks KenBar for the info on the radio. I will try to find a better quality one or just do a mod on one that I know is good quality.


----------

