24V to 12V DC-DC 30A Car Power Supply Inverter Converter Conversion Device
Convert your DC 24 volts to DC 12 volts with this compact power supply converter

My power supply inputs 23.81 Volts and this unit outputs 11.62 Volts.

HEAT!!! I added a small fan, 25mm inside connected direct to the 12 Volt output pads inside. I have also put it, the RAMPS and SSR, into a box with a 70mm computer fan. I, not fully tested found the case, outside, of the unit, (this is used as a heat sink), getting quite hot, this seemed to be more, (not fully tested), when I powered a small 12 Volt light strip from it, Low Amps.

So do not use it without external cooling.?

I now power the LED strip and fans from the red 12 Volt output, lower Amps output, of this unit and the RAMPS 12 Volts from the Yellow higher Amps output.

The RAMPS caused some flicker to an LED strip, passing some voltage PWM form hot end to the RAMPS input.

The circuit is now like this:-

https://hackaday.io/project/8680/gallery#d2769ed6055a46e72534c2ed2e978abb