I am trying to power a cabooses lights with a 9 Volt battery. I have 3 LED's which if I am not mistaken equals 9 volts. I connect them as they should be but two of them keep burning out. What am I doing wrong?
your drawing to much current led's are only designed for 20ma or so you need to use a resistor to drop enough voltage so the current is much lower! I would suggest you try n run from track power with a diode in series with a dropping resistor and led plus add 220 ohm resister! I think you'll find out just before they burn out they get very hot and then short or open !
My guess is you wired them in parallel to the battery, that's not a proper configuration.
Wire the three white LED's in series and then connect the 9V battery, you'll have much better luck. I'd recommend adding a 150 ohm series resistor as well.
I suspect you don't have power pickups on the caboose, right? If you have power from the track, Alan is obviously right about using track power.
I have added lights to a couple of cabooses with a 9 volt battery and an on/ off switch using LED's from Evan Designs. They cost a little more, but use built in resistors and are a breeze to hook up. I've never had one burn out.
Well....Speaking of Evans Designs, I'm currently in the process of installing one of their items in another Ambroid kit caboose build. The ED item I'm using is their 3VFRED, a kit for installing a battery powered red flasher EOT device.
Now, if you're lighting a modern caboose that has a red flashing EOT light, you'll be able to use the 1.8mm red flashing LED that comes in this kit. For my transition-era cabeese, however, I set aside that kit LED for another project....some day, maybe.
The items that come in the kit that I'll use are a Cr2032 coin-type lithium battery, the battery holder, a pre-wired harness incorporating a push-on-push-off button switch, some bits of shrink tubing. The instruction sheet that comes with this kit has the following statement..."You can connect up to 10 LED lights to this unit. Ten lights will run for about 12 hours, then you need a fresh battery." Bingo!
So, I'm installing a couple Tomar LED marker lights and a single interior (nano) desk light, 3 LED's total. You can use any LED, but you must honor the correct polarities when attaching them to the harness, red wire to +, black wire to -. Additional resistors not required, since the power is 3V.
On the Ambroid (wood structure) cabeese, I've simply drilled a hole in the floor in a convenient location near one side of the car for the push button to extend through. Painted the appropriate undercar color, the button is quite unnoticeable. Depending on your dexterity, you might even glue a small styrene rod/tube extension to the button to make it more accessible. When I construct the Ambroid caboose kits, I create a removable car side panel, held in place with 6 tiny neodymium magnets, to facilitate installation of the electricals, as well as make replacement of the battery very convenient. I have yet to replace the battery on the first caboose I so equipped, built 3 years ago!
OK, OK....It's not for everyone. I've tried selling this idea to a variety of our (LHS) customers. Having batteries that can corrode through neglect on board your treasured trains is a no-no to the diehards. OTOH, having on board 3V power for car lighting without sourcing through track voltage.....IMHO, of course....is a BIG plus. The ease of installation, flicker-less lighting, convenient, inexpensive batteries, etc., etc.,.....I may be converting some of my factory-made RTR cabeese down the road.
Oh yes,....current retail for the above Evans Design kit is less than $6.....hardly a budget-buster.
Hard to understand why I wouldn't use track power for an already lighted caboose. The parts to power the flashing LED and the flashing LED are around 75 cents, a diode, a cap, and a CL2 constant current source. Add flashing LED and you're set.
Truthfully, it isn't hard for me to understand why it's hard to sell the battery idea to the customers.
In my case, one caboose was a cheap model with no lights. The other was another cheap lighted one in which the pickup roller system was beyond repair. A simple fix and no more flickering light.
The already lit caboose would have been great but for some reason this caboose would ground out a cause a short. I examined everything thoroughly and I could not find the reason why it did this. I have all of the LED's I need but I do not know what CL2 is. I have a simple circuit for constant voltage but I found a YT video that show a 330 resistor being used. I will try that so I do not have to worry about blowing those two lights out. I made my own sockets with polystyrene tubing so pulling LEDs in and out are easy to replace. I will post pictures when I am done.