Easy LED Light for 9V battery

zelph

zelph

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Extra large/bright LED and terminal connector available at Radio Shack. Use shrink tube to encapsulate, use exacto to cut around terminal studs. connect to long life lithium 9V battery when needed. Just something I made a while back. One year later someone came out with a commercial one.

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So did you have to solder it to the terminal cap?

Thanks! Great idea!
PMZ
 
Yes, I used a resistor in line. Don't remember the mA Forgot about that, sorry, thanks for the reminder. I did have to solder to make it secure for all time and eternity.

the one photo shows four wires coming out of the credit card size pack of magnesium shavings. those are "starters" for hobby rocket launchers. They make good electronic fire starters in a pinch. They did light the magnesium no problem. Yes I like to play with stuff like this. Keeps me out of trouble. In the wrong hands it could get you in trouble.:54:

The little black things are terminal covers for the battery when not in use. Helps prevent shorting out when in storage.

somew additional photos of the other stuff

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How did you solder such a tiny little thing without burning out the bulb?

For that matter, how'd you hold onto it?

I'm trying to visualize this...lol. I tried doing that once and failed miserably. The solder just rolled right off the leads...maybe my iron's too big? Or the solder is the wrong kind?
PMZ
 
Trekon86 said:
How did you solder such a tiny little thing without burning out the bulb?

For that matter, how'd you hold onto it?

I'm trying to visualize this...lol. I tried doing that once and failed miserably. The solder just rolled right off the leads...maybe my iron's too big? Or the solder is the wrong kind?
PMZ
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A small three clip soldering vise. Small soldering iron, no caffene, steady hands. Heat the leads with a solder iron that has solder on it so the solder gets on the leads. After it cools, align with leads to terminals, apply solder iron that has a drop of solder hanging from it.

vise:
http://www.amazon.com/dp/B0006NDZR6/?tag=bcusa-20

Do you have a source for the commercial version?
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http://www.9voltlight.com/
 
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Have the comm. version running for 4 years on the Elec.Panel.. do it, nothing worse than a power fail and your not home to guide your loved ones.
 
Trekon86 said:
How did you solder such a tiny little thing without burning out the bulb?

For that matter, how'd you hold onto it?

I'm trying to visualize this...lol. I tried doing that once and failed miserably. The solder just rolled right off the leads...maybe my iron's too big? Or the solder is the wrong kind?
PMZ
Click to expand...

You could be right about the type of solder. But the size of the iron only depends on the type of work you're doing. When I made taillights for my bike and accessory LEDs, I used a temperature control soldering station.
 
If you go to "instructables.com", and enter 9v LED light, you will find several tutorials with written and picture directions for making one. Some complete with circuit diagrams, resistor ohm ratings and various other led suggestions.
 
Twinsteel said:
Would like to know the resistor type if you can remember. Or would any kind work?
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Simple calculator to figure out the right resistor for a given application.

The forward voltage(Vf) on the LED varies for the desired current. Each LED is unique to some extent based on design. You can look up the datasheet for the LED to figure out what current you want and the Vf at that current. Calculator will do the rest to get you the appropriate resistor rating.

In this application you probably want less than the max current the LED is spec'd for. There's basically no heatsinking except through the leads on these types of LEDs and in this design they don't really take the heat anywhere it can effectively dissipate. Max current on some of these 5mm LEDs usually greatly reduces service life/brightness due to heat.
 
pzampino said:
IIRC, you should always in-line a resistor with an LED to prevent too much current from flowing through the LED and destroying it.
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With a 9v and a single one of these 5mm LEDs that's a good starting point.

In general you don't always need a resistor though depending on the LED and the voltage source. In some cases the LED can handle more than current than direct drive without a resistor will push from a given voltage source. (A red 5mm LED with a single AA is an example.) Adding a resistor then just reduces current/output or prevents it from even lighting. In other cases adding too little resistance still overdrives/smokes the LED.

I'm a big fan of taking the couple minutes to pick an appropriate resistance, or none at all, instead of winging it.
 
Redbusa06 said:
Did you use any resistor in-line with the LED? what's the mA on it?
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zelph said:
Yes, I used a resistor in line. Don't remember the mA Forgot about that, sorry, thanks for the reminder. I did have to solder to make it secure for all time and eternity.
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Some LEDs have built in resistors, but if yours doesn't, you need to add one or the LED will burn out. The LED probably can handle 20 ma easily, and will drop 1.5 V of the 9V. So your resistor, which will drop the remaining 7.5 V, needs to be about 375 Ohms (R=Volts/Current). A 330 Ohm, 1/4 watt resistor will work fine.
 
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Vipers said:
With a 9v and a single one of these 5mm LEDs that's a good starting point.

In general you don't always need a resistor though depending on the LED and the voltage source. In some cases the LED can handle more than current than direct drive without a resistor will push from a given voltage source. (A red 5mm LED with a single AA is an example.) Adding a resistor then just reduces current/output or prevents it from even lighting. In other cases adding too little resistance still overdrives/smokes the LED.

I'm a big fan of taking the couple minutes to pick an appropriate resistance, or none at all, instead of winging it.
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I can't argue with that.
 
Vipers said:
(A red 5mm LED with a single AA is an example.) Adding a resistor then just reduces current/output or prevents it from even lighting. In other cases adding too little resistance still overdrives/smokes the LED.
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I would love to get my hands on a 5mm red led with a voltage req around 1.5 volts (without using a joule thief or transistors). I have seen 1.7, but not as low as a single cell. Got a link?
 
ajnin said:
I have seen 1.7, but not as low as a single cell. Got a link?
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Allow me to be the demonstrator of why consulting the datasheet instead of SWAGing it is a good idea. Threw that out quick from memory of about the lowest point where some current will flow... and was wrong. Sorry for the hope.
 
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