I was reading a older post from here:
https://forum.allaboutcircuits.com/threads/modify-240v-ac-led-buld-to-work-on-12v-dc-battery.131614/

Where a person answered this:

"You are on the right track. Inside the lamp is a power supply that drives the LEDs. The power supply probably would not work at all at 12 volts, so you will have to remove or at least bypass the power supply."

Can anyone help me explain how one can find and locate the power supply inside the LED bulb that drives the bulb? Is it then possible to just remove that part? And what should one do to replace that power supply to make it work on a 12v DC battery?

 

The chances are any mains leds are going to be multiple wired in series, so the voltage will vary depending on how many leds there are, most leds need 3V to work.

Best option is to post pictures of the inside if your mains led fitting then we can advise.

 

I have some little LED night lights and everything in there (except the LEDs) is useless for a DC application.
To make mine work, I would:
Take the LEDs out, put them in series, and use about 150 ohms in series with the LEDs.

 

I have a failed LED on my workbench. The reason for the failure is one of the two incoming resistors (10Ω) is completely crispy critter'd. The output leads have a capacitor across the output. It's of some farad rating, I'm not at my bench right now. But the cap voltage is rated at 80 VDC (electrolytic). So I'm GUESSING that when in normal operation this particular LED light bulb probably had a final voltage of around 40 volts with the LED's in series.

If you want to run a standard LED bulb on 12 volts then you're going to have to modify that voltage, probably with a buck converter - provided you can get one that can boost 12 volts up to (around) 40 volts.

Hadn't thought of that before. Maybe I'll consider this as a future project. Right now I'm in the process of building a marble machine for my grandchildren. (all enclosed in plexiglass so no choke hazard for sure. The only thing accessible will be the starter button and the battery case. Everything else will be behind covers and closed with security screws so that the little genius (Clark) can't open it and take it apart. (He's a lot like me - at age 7 I took my dad's brand new gas mower apart to see how it worked)