Just want to show off my latest project.
I recently bought myself a 1979 camper trailer that was completely original.
It had 12V light fixtures with BA15S and 41mm Festoon bulbs.
I wanted to change them out to LED to minimize power usage when I’m camping, but finding any LED bulbs that looks decent with a good CCT, tint and preferrably high CRI is quite difficult from my experience. I’d go so far to say it’s impossible.
Being a fan of rngwn’s 5mm LEDs, I started thinking of 3D printing bulbs with these LEDs in them. So by measuring and doing a couple of prototypes, I made these bulbs:
This was the first project, replacing a 10W incandescent BA15S bulb. I went with four 2300k >95CRI 5mm LEDs in series, drawing 20mA each when input power is at 13,5V with a 120Ω resistor.
The “optic” is 3D printed transluscent PETG.
It’s basically just a holder for the LEDs, with a 0,2mm bottom layer as the lens to give them a bit more flood.
I am pretty happy with these. Unfortunately no comparison pictures between original and new here, but the next bulb will do justice showing off the light color of these LEDs:
These are 5W incandescent 41mm Festoon bulbs, and I also went with four 2300k >95CRI 5mm LEDs in series here.
I am really happy with how these turned out.
The end-caps are salvaged from other LED bulbs bought online that had a horrible color to them. They are press-fit onto the end of the body, with the negative LED pin and a resistor on the positive side jammed in-between the cap and the body. No soldering to the end-cap needed. Printed in the same transluscent PETG.
Closeup of the bulb.
Backside, basically just soldered in series and with a 120Ω resistor at the positive.
Simple and quick to make. Each bulb takes about 10 minutes to print on a Prusa i3 MK3 at 0.2mm layers.
This side can be hot-glued to make them sealed, but I chose to keep mine open for now. No worries when they’re used in indoor fixtures.
Here’s a comparison of the bare bulbs, WB @4000K
The LEDs are actually slightly warmer than the incandescent, but not as noticeable in person. Brightness is about the same from the front, but the incandescent looks brighter because of the bloom.
I’m considering sanding the front of the LEDs to give them a bit more flood in these fixtures.
Comparison with the cover on. Incandescent at the top, LED at the bottom.
From the side…
Made ten of them, eight in one go. Pretty fun! Probably going to do this for the bulbs in my old cars too.
Here’s the result!
Now, for energy comparison: I had ten 5W and two 10W bulbs in the camper. In total they had a current draw of about 4.63A in 12,5V. That’s about 58W. There were probably some voltage drop in the cabling and fixtures.
With the new LEDs it all has a power draw of… 0.2A in 13V. That’s a hilarious 2,6W.
22,3 times less power, but still lighting the camper up like it did before… almost, overall brightness is slightly lower, but that’s just a plus.
I’m going to refine these STL files and post them on Printables and Thingiverse, stay tuned for the link. I will provide all different standard lengths of Festoon bulbs, with a fitting amount of LEDs. Note that these 2300k LEDs are 2mm shorter than regular LEDs, so regular LEDs will protrude a bit more out of the shell.
Cheers!
