# Battery power for LED headlight.



## Scottychaos (Jan 2, 2008)

I have a headlight from a Bachmann Connie:










(there are actually 2 wires coming out the back, only one shows in the photo)
it is a LED bulb..

I would like to hook this light up to its own self-contained battery, with an on-off switch, so I can use it on another project..


What size battery would I need? (voltage)
and..I know LED's need some kind of diode, or capicator, or something, in the circuit to make them work..what is that exactly?
could anyone describe (or diagram) the basic circuit that would have to be built to make this work?
thanks!
Scot


----------



## BillBrakeman (Jan 3, 2008)

Scott triy this WEB Site *http://www.ehow.com/how_4836713_design-simple-led-circuit.html *


----------



## BillBrakeman (Jan 3, 2008)

Okay! How did I get three copies of my post? 
:


----------



## Greg Elmassian (Jan 3, 2008)

Slow internet connection, or you clicked submit 3 times... 

Scott, you did not ask, but how long do you want it to run? If you have the room, use 3 D cells... you will get the longest run time. 

You can calculate it by finding the amp hours of the battery... you know you will use 0.020 amps per hour ... with those 2 numbers, you can calculate how long it will run. 

Regards, Greg


----------



## Semper Vaporo (Jan 2, 2008)

I wrote an article for Steam in the Garden magazine where I made the headlight from copper pipe caps. You already have the light holder so you won't be able to follow exactly what I did, but I have found that a single LED will run quite nicely and a LONG time on just a simple 3-Volt Lithium "coin-cell" battery. 

I connected a CR2032 battery to an LED and it remained lit for well over a month, CONTINOUSLY! 

I created a switch by drilling and threading a hole for a tiny brass bolt to touch the battery (otherwise insulated from the case of the LED holder. 

In your situation I think you can connect some longer wires to the leads you have and run them to a small on/off switch and then to a coin-cell holder (or just make the coin-cell holder easily accessible so the battery can be removed when you don't want the light on). 

There are several sizes of these 3-Volt Lithium Coin-cells, the 2032 is about the size of a U.S. Quarter coin, maybe twice as thick. There are also some about the size of a Dime that will last for a week of continous use. Since you will probably want to shut the light off except when your are actively running the engine, these batteries will last a couple of years before you notice the light is not as bright as when the battery was new.


----------



## Tom Parkins (Jan 2, 2008)

I used a 9 volt battery I think with a 200 ohm resistor and it lasted all summer +. Depends on the voltage of the LED. Don't need to waste the weight using D size batteries. Even AAs or AAAs will last a very long time. LEDs take very little current.


----------



## Stan Cedarleaf (Jan 2, 2008)

Hi Scot.... Like Semper.... I've found a *very easy* way to do this using the following coin battery holder for use with a 2025 or 2032 battery.

They are 3 volts and will drive an LED without resistors All you need is an LED, battery and a switch. You don't even need a switch if you want to just remove the battery when not in use.

I've been running this type of hookup for 12 years without a failure of an LED not using a resistor.







One reminder is that the long leg of the LED goes to the positive lead. Short to negative. The other way is very hard on LED's. They go phhhttttt.









Available from All-Battery or Radio Shack.


Battery Holder Description


----------



## Scottychaos (Jan 2, 2008)

excellent, thanks everyone! 
Stan, looks like your method wins the award for simplicity!  
I will give it a try.. 

as for positive or negative leads, this light has a white and a black wire coming out the back.. 
which is positive and which is negative? 
I googled it..and I found answers for both..(white +, black neg and black +, white neg ) 

thanks, 
Scot


----------



## Scottychaos (Jan 2, 2008)

Posted By Semper Vaporo on 05 Sep 2011 10:27 AM 
I wrote an article for Steam in the Garden magazine where I made the headlight from copper pipe caps. You already have the light holder so you won't be able to follow exactly what I did, but I have found that a single LED will run quite nicely and a LONG time on just a simple 3-Volt Lithium "coin-cell" battery. 

SV,
what issue of SitG was that? (I just went through my entire stack of issues, going back to 2003, and didnt find it..) 

thanks,
Scot


----------



## Semper Vaporo (Jan 2, 2008)

Posted By Scottychaos on 05 Sep 2011 07:58 PM 
Posted By Semper Vaporo on 05 Sep 2011 10:27 AM 
I wrote an article for Steam in the Garden magazine where I made the headlight from copper pipe caps. You already have the light holder so you won't be able to follow exactly what I did, but I have found that a single LED will run quite nicely and a LONG time on just a simple 3-Volt Lithium "coin-cell" battery. 

SV,
what issue of SitG was that? (I just went through my entire stack of issues, going back to 2003, and didnt find it..) 

thanks,
Scot 



Issue 73 November/December 2003, Page 39-42, "A Self-Contained Working Headlight".


----------



## nkelsey (Jan 4, 2008)

Stan, seems to me a piece of thin styrene to slip under the sprung contact would be an easy turn-off method.


----------



## Paul Norton (Jan 8, 2008)

Posted By Scottychaos on 05 Sep 2011 07:28 PM 



as for positive or negative leads, this light has a white and a black wire coming out the back.. 
which is positive and which is negative? 
I googled it..and I found answers for both..(white +, black neg and black +, white neg ) 

thanks, 
Scot 
Scot, in my Annie the colour coding of the rear light was not the usual red for positive, black for negative. However if you hook the wires from a 3 volt battery pack the wrong way to a 3.5 volt LED it will not light, the right way it will.

I am concerned that this may be a 2 volt orange LED. You might want to try touching the wires to the ends of one AA cell. If it lights it's a 2-volt LED, if not it a 3.5 volt LED likethe bright whites.


----------



## Scottychaos (Jan 2, 2008)

Thanks Paul..
im not sure which LED is on the light! but I know how to find out..heading over to youtube! 
Connie vid 1

Connie vid 2

yep, looks like its probably the "2-volt orange"..I will look at the light tonight and see if it comes apart easily,
if so, I will try to swap out the bulb..

thanks,
Scot


----------



## noelw (Jan 2, 2008)

Posted By Stan Cedarleaf on 05 Sep 2011 04:14 PM 
Hi Scot.... Like Semper.... I've found a *very easy* way to do this using the following coin battery holder for use with a 2025 or 2032 battery.

They are 3 volts and will drive an LED without resistors All you need is an LED, battery and a switch. You don't even need a switch if you want to just remove the battery when not in use.

I've been running this type of hookup for 12 years without a failure of an LED not using a resistor.







One reminder is that the long leg of the LED goes to the positive lead. Short to negative. The other way is very hard on LED's. They go phhhttttt.









Available from All-Battery or Radio Shack.


Battery Holder Description











To Stan C........
Short to negative. The other way is very hard on LED's. They go phhhttttt.








*Now that a neat one Stan.. still laf. I'll have to try that and see if I can hear that sound*........


----------



## Semper Vaporo (Jan 2, 2008)

Posted By noelw on 12 Sep 2011 02:35 PM 
Posted By Stan Cedarleaf on 05 Sep 2011 04:14 PM 
Hi Scot.... Like Semper.... I've found a *very easy* way to do this using the following coin battery holder for use with a 2025 or 2032 battery.

They are 3 volts and will drive an LED without resistors All you need is an LED, battery and a switch. You don't even need a switch if you want to just remove the battery when not in use.

I've been running this type of hookup for 12 years without a failure of an LED not using a resistor.







One reminder is that the long leg of the LED goes to the positive lead. Short to negative. The other way is very hard on LED's. They go phhhttttt.









Available from All-Battery or Radio Shack.


Battery Holder Description











To Stan C........
Short to negative. The other way is very hard on LED's. They go phhhttttt.








*Now that a neat one Stan.. still laf. I'll have to try that and see if I can hear that sound*........












I've never had an LED go phhhttttt when I hook them up backward. I can never remember which lead is positive or negative, nor which end of the battery is positive or negative either, so I hook the LED to the battery and if it Lights up, then it must be right and if it doesn't I reverse the leads and it then lights up okay.

I have bent the needle of my VOM into a questionmark shape when I went to see of there was 120-V at the power outlet but forgot to rotate the switch to 250-Volts AC, having just made a 0 to 100 Ohm resistance measurement! But that made more of a KAPOW sound rather than a phhhttttt. (I made other sounds the rest of the day, but this is a family forum so I won't attempt to spell them here!)


----------

