Q about battery power

I'd probably recommend using three 1.5 batteries and wiring the LED's in parallel using the CL2 constant current chip.  You are wiring batteries with dissimilar amp-hour ratings together, never a really good idea.  How many LED's are you trying to light?

I'd suggest an alternative.  Wire up a simple power supply and use a super-cap to power the LED's when you're stopped, the super-cap is charged when you're running.  No batteries to buy.

LEDs by themselves are only 2 to 3 volts. Running 12 volts to it is a waste of power unless you run 3 LEDs in series. 75% of it is wasted in the resistor for the single LED. Better to use a 3 volt battery and a 1 ohm resistor.

John also has a good idea.

I run conventional and use this circuit for passenger car lighting. On the regulated side I put 5, 1 farad capacitors in parallel. This leaves the lights on a couple minutes after power is removed. They dim slowly over time,even after an hour you can see a very faint glow in a dark room. The super caps are not shown but easy to add,spaced between the LEDs.

www.jcstudiosinc.com/BlogShowT...=408&categoryId=

Dale H

Yes.

If in light of above comments you want/need to stay with 12V, do you have room for, say, 8 x 1.5V of AA or AAA? To John's point, a typical 9V alkaline battery will discharge 4-5 times faster than a AA and 2-3 times faster than a AAA.  You can go to the Energizer bunny website and read about it till your eyes glaze over...

Plus 9V worth of AAA or AA batteries seem to be cheaper than single 9V batteries.

I thought I’d show what I’m doing. I’m using a 6” Marx frame to light up some custom made passenger cars.  I’m not sure what a super caps and farad capacitors are but ready to lean. Not a whole lot of room to work with.
Greg

Taking your original question at face value, I'm inferring you want more brightness and that the battery-life is acceptable as-is.  I made the following for another LED passenger car thread showing how the brightness of these 12V LED strips varies with applied voltage.  Brightness is on the vertical axis shown in units of current but is exactly proportional to light output for LEDs.  So for the strip I used, at 9V the brightness is 2.5 going up to about 18 at 12V.  So, yes, if you could supply 1.5 or 3 more volts you would indeed see a dramatic improvement.  But in a classic case of "don't raise the bridge, lower the river" how about modifying the LED strip from a 12V strip to a 9V strip?

Note that on your strip there's a small black part on each section of 3 LEDs.  I can't quite make the lettering out in your photo but it probably says "151" on it or something like that.  This is a resistor which you can short out with a small piece of wire.  By doing so you essentially turn your 12V strip into a 9V strip which will be remarkably brighter using just your 9V battery.  If you have a pair of metal tweezers, you can try this in a few seconds by shorting (putting the tweezers across the ends of the resistor) one of the two resistors on your strip and comparing the two sections.

Of course this is just one idea which I will explain further if need be.

The individual LEDs I use with the regulator and super capacitors would take up less room than the battery uses. They could be mounted on the roof of the car or floor. 3 LEDs would light probably the car shown. Lighting would also be constant voltage.

These are for 18 inch cars using 6 LEDs, but shorter versions can be made. The super capacitors would be mounted between the LEDs.  They are about the diameter of a quarter and about 1/4 inch thick. The fish paper used only need be only 3/4 inch wide.

Dale H

Note for the track power option, you need at least one truck with a collector, something to consider.