Hi, I am new, here is my first modded light

[Hellbore]

I'm new to this hobby but it looks fun! Here is what I made if you want to see:

http://cleedo.com/blacklightmag.html

Yeah I know it's not much but I'm new to this. I hope to do cooler stuff in the future using voltage regulators and stuff.

Also, before finding this forum I ordered an EverLED to put in my other 3D cel Mag Lite. I hope that wasn't a mistake! Are EverLED's any good?

 

[Rothrandir]

nice mod!

i think that's the most i've seen crammed into a pr2 base...good job! /ubbthreads/images/graemlins/thumbsup.gif /ubbthreads/images/graemlins/grin.gif

the everled is a nice module, but it's always better to do your own modding /ubbthreads/images/graemlins/wink.gif

 

[Xenon]

Nice and useful mod. But the scorpion with the babies doesn't goes down well with me. Scary stuff.

 

[Hellbore]

Well I am worried with this mod if the leds will burn out from too much current. There is no resistor or anything. They are all wired in parallel. I guess I need to do more reading.

A friend told me today that too much amperage is what will fry an LED. However I had always thought that amperage was somethign that your particular component would consume a certain amount of, and that having more amperage than that wouldn't necessarily mean your component would USE more amperage, more woudl just be available. Does that make sense or do I have the wrong idea? So why would an LED burn out when run off a higher amperage battery and not burn out when run off a lower amperage battery?

Anyways if you don't want to answer my dumb questions then maybe you could point me towards where I can read the answers /ubbthreads/images/graemlins/smile.gif Thanks!

 

[charliek]

Nice mod- But with no resistors those LEDs won't last long
Nice arachnids too... /ubbthreads/images/graemlins/smile.gif

 

[Orion]

Great job for a beginner! And, . . . .awwwweee!! Cute baby scorpions!!! /ubbthreads/images/graemlins/smile.gif

 

[charliek]

I'm sorry-
Here is some real help for newbies:

http://trotto.zmoz.com/led_pro.htm

Download this program- it makes it EASY... /ubbthreads/images/graemlins/smile.gif

Keep up the good work, and keep posting!!

 

[onelight]

Nice mod....YOU NEED TO MOVE befor all those babies grow up! /ubbthreads/images/graemlins/faint.gif

 

[Tim_Z]

Hello Hellbore.

The statement your friend made is correct for most things (i.e.) My computer has a 450W power supply but only uses, say, 300W; the rest is just in "reserve".

However, an LED will act like a short circuit and try to pass as much current as it can. Therefore you need to add a current limiting resistor in series with your LED array. I am not familiar with these new SUPER-LED's but the formula would look something like this:

Keep in mind that current is the same in a series circuit (each device in series gets the same amperage but different voltage) AND Voltage is the same in a parallel circuit ( each parallel leg in the circuit will get the same supply voltage but diffent current).

R=E/I.
So once you know the supply voltage (Vs), the forward voltage of the LED's (Vf) and the forward current the LED's can safely handle (I) then you do some math amd can figure the resistor value (R).

R= (Vs - Vf) / I

So as an example if you had a 6v power source (Vs) and your forward voltage of the LED is 2.0v (Vf) and forward current of the LED is 100mA (.1 A) (I) then it would look like this:

(6-2) / .1 =

4 / .1 =

40 ohms for (R)

So since the LED is basically a short circuit the Resistor would drop 4 volts , which with the LED's 2 volts equal 6 volts, at .1A since current is the same in a series circuit the LED will also have .1A.

I hope this sheds some light on your situation (no pun intended, really!)

WOW, haven't used that knowledge in 17 years.

 

[Hellbore]

OK, I'm not understanding the way the current works.

According to this formula, if I had the right voltage that matched the LED's forward voltage, I would not need any resistor regardless of the Ma of the power supply, because Vs - Vf would equal zero... That doesn't make sense to me because you said the LED will act like a short and draw as much amperage as is available. So, I'm not understanding this.

Also, I looked at this info sheet on the LED's:
http://www.superbrightleds.com/leds/uv_specs.htm

At the bottomm, the graphs... I looked at the one on the far left. It would appear to show that the LED will only draw a certain current at certain voltages. For example 40 Ma at 4 volts. So wouldn't an LED draw something like 60 Ma at 4.5 volts (following the slope of the graph's line) rather than trying to draw the entire 1500 Ma or whatever that the batteries have available?

It just seems to me like if the LED would draw all the available Ma it would have burned out by now already. I have used the light around 6 or 7 hours so far and the leds look the same and they don't get warm.

If I'm not mistaken the 6 LED's in parallel should eat up something like 360 Ma since they are being driven at 4.5 volts. Don't D cells have more Ma than that?

Part of my confusion that is pissing me off is that I don't know what the hell the Ma of a D cell battery is! Can someone please tell me? It doesn't say on the battery!

 

[Ginseng]

Yikes!

Nice mod. Glad I don't live in a part of the country that has scorpions as pests.

Wilkey

 

[charliek]

I'm not sure if those Scorpions were pests or *pets*

 

[Hellbore]

LOL... I actually had that mother scorpion and her babies as a pet, but I have a lot of nieces and nephews who are toddlers and there was to great a risk of them tipping over the terrarium or otherwise getting stung, so I relocated the whole lot to somewhere far away from the house /ubbthreads/images/graemlins/smile.gif

I like scorpion hunting but I don't kill the scorpions. Call me crazy... They just look so cool glowing green, and if I kill them I won't have any to hunt for /ubbthreads/images/graemlins/smile.gif

So... Anyone who can clear up my confusions about Ma and LEDS?

 

[charliek]

I recognized the species as a commonly kept pet....

I like Scorpions as well.... I have one tattooed on the left side of my chest.


As for the LEDs.... you should download that program I sent the link to- makes everything very easy.

 

[Hellbore]

Well those are abundant here, if you want a couple I can send you some /ubbthreads/images/graemlins/smile.gif They are very hardy and woudl probably survive shipping just fine lol

About the program, I already downloaded it and same problem. If I tell it that I want to run the LED's at 4.5 volts it says I don't need a resistor (comes up 0 ohms)! So there's no way to limit current without limiting voltage too?

 

[jtice]

Hellbore,

Let me know what you entered into LED Pro.
I have found a "bug" in it the last few days.
You CANNOT enter "0" as a value. it will crash /ubbthreads/images/graemlins/icon15.gif
I will be fixing this very soon. Updates on the way.

What did you enter into LED Pro to get 0 for the Ohms?

 

[tvodrd]

Hellbore, (A fellow Keith Laumer fan?)

Welcome to the forums. I am on my 5th generation of UV lights for scorpion hunting. I hunt to keep the population down near my get-a-way shack near Landers, CA. I murder them.

Larry

 

[charliek]

[ QUOTE ]
jtice said:
You CANNOT enter "0" as a value. it will crash /ubbthreads/images/graemlins/icon15.gif
I will be fixing this very soon. Updates on the way.

What did you enter into LED Pro to get 0 for the Ohms?

[/ QUOTE ]

You get a "DIV/0" error...
For zero ohms- enter a very low value like .01
We're not dealing with rocket science here... the closest resistor you will use is usually off by quite a few ohms, and you'll probaly be using a 5% tolerance resistor that adds even more error.... Here, all you need to get is "close"

 

[jtice]

charliek,
While that may be true, I am a perfectionist.
And this eroor and crashing is NOT cool with me.
Its not a real hard fix, I just havent had time.

Yes, I do the same trick, by entering something like 0.0001

But, Hellbore was saying he got "0" for Ohms. I would like to know how he did that.

[EDIT] I am not however, a perfectionist, when it comes to my spelling. /ubbthreads/images/graemlins/blush.gif [EDIT]

 

[AilSnail]

Remember even if you have 3 cells you don't neceserrily have 4.5 volts. Without load they might be more, and with load applied they can be less.