12 volt halogen bulbs

[the big dipper]

Here's something I'm workin on.

I clamped some leads on to one of the little 12 volt halogen bulbs that are commonly used for undercounter lighting. (They normally run off a 120v - 12 v transformer)

The bulb is a 20 watt - and lights up very nicely - one problem though is that the connector prongs on the bulb are stainless (I think?) and solder won't stick so a factory connector would be nice to get ahold of.

As I have'nt yet used it in for actual icefishing - I'm not sure how long it will run on a typical 12 volt - 7.2 amp gelcell battery. Maybe if any of you guys have a spare bulb laying around you can try this also, and see how it works.

One down side is that the bulb gets hot, and if it happened to drop either into the snow or water I'm afraid a minor explosion might occur.

[DCON]

I'm no electrician, but i think that with heat comes alot of current loss Im sure they go hand in hand, might want to consider a smaller base bulb or a smaller wattage

[the big dipper]

I devised a pretty effective and easy way to both protect the bulb and make a reflector/shade. I took a sheet of alum. foil, folded it double into a 5"x12" strip and then wrapped this around the bulb and the cord and then kinda squashed it all down so that it attached to the bulb/cord thus providing a reflector that directs all of the light down, an at the same time protects the bulb and makes it cool to handle. Actually, the unit did not heat up much past the "warm" stage where it can be easily handled, so I wonder how much current is lost to heat.

Amps = watts divided by volts so a 20 watt light 12 volt will use 1.6 amps/hr.

So going by this formula a 7.2 amp battery should provide 4.5 hours of light on a full charge.

a 15 watt bulb calculates to use 1.25 amp hrs, so this will extend

your use time out to 5.76 hours of light, and a 10 watt bulb will run for twice as long on the same battery as a 20 watt. ( 9hrs -vs- 4.5hrs)

[the big dipper]

Have any of you guys tried these bulbs? I think it's going to help solve the lighting problem for me.

[ryan johnson]

ok now here it goes..they are right about how long those wattage bulbs will last,,but the fact is that the colder the filament in the bulb the more current the resistive element will draw..For example when do see bulbs blowing most often? In the winter, outside,when you first turn on the switch the cold filament of the bulb has little resistance,thus allowing current to go through the wire unempeded.

the huge amount of current in this fraction of a secound will sometimes melt the the wire in the filament..if the bulb can handle this early onrush of current it will do fine,because it heats itself up almost emediately..

now when it comes to bulbs you get no advantage or disadvantage in haveing a 120 volt 20 watt bulb or a 12 volt 20 watt bulb except that for the 12 volt system you will have to have larger wire..50/12=4.1 amps as aposed to 50/120=less than half an amp(don't have my calc.lol)

when you buy a bulb it will say on it 40 or 60 or 100 watts for example this means how much energy it will use..(watts=volts*amps)..not how much light output it will produce..light output is expressed in lumens..

as you will see in the new compact floresent bulbs that say 10 watts equivelent to a 60 watt bulb..this means they put out as much light as the old 60 watt bulbs..

I'f you have a chance i would try to obtain some LED bulbs that are commonly used to power exit signs(usually retrofit bulbs are the best)and try to work them into your lighting scheme..here's a picture of them..except that the ones pictured here glow red.you can get them in white..

the two on the left use 1.5 watts of energy and replace a 15-20 watt exit bulb..

[image]http://im1.shutterfly.com/procserv/47b4cf23b3127cceaa5fcb01cd070000001610[/image]