LED 2-pin bulb with built-in convertor

Hi I'm new here but I'm making joule thief flashlights.

I found this neat G4 LED bulb with voltage convertor in it. It's only $.99usd, input is 12vdc or ac it says. Power usage about 1.5w. Has anyone used these? What do you think of them?

These are also G4 bulbs that require 12v as input. Too bad it won't work with my Ryobi One flashlight. Has anyone found a good deal on a standard flashlight bulb that fits the Ryobi One flashlight? Because the battery is 18vdc. That seems to be a major sticking point for finding these.

I may not have had the same exact Ryobi 18V flashlight as you, but this is what I did.
A really, really easy 10 minute 18V power tool flashlight mod.

Thanks, yes that’s the Ryobi One light that I have. I guess now that I have PCB board I could make an LED light for this myself.

can you put that led bulb on a variable power supply and see what happens when you raise voltage?
ones made with a bridge and resistor will increase in current.
the good ones will reach a voltage above vf of the led string and then decrease current as voltage rises.this type has a buck converter.
this type is what you want for the power tool conversions.the ones i got at walmart are different yet.instead of a buck they have a linear regulator.these are no good either.