Need a little electronics advice

[Spanky]

I have a circuit that lights three separate LEDs, outputting about 4.5V for each.
Instead of classic LEDs, I want to use G4 equivalents. So I need to up the outputs to 12V and each G4 LED will pull up to 2W.

 

[Funhouse71]

The way you possibly do it could do it is by getting a bit of breadboard and mount 3 x HE3621A0510 reed relays on it. HE3621A0510 reed relay has a min. coil operating voltage of 3.65v and switching current of 0.5A with a carry current of 1.2A so your 4.5v so should be enough to drive the coil in the relay.
Reed relays by design are silent in operation so no clicking sound in operation. At 12v 2w each bulb will pull approx. 170 milliamps



Connect GND of your original LED light circuit to pin 3 and 4.5v positive output to pin 2 to drive the coil of the relay then have a separate 12v power supply with the GND connected to the negative on the G4 bulb and then the positive of the 12v power supply connected to pin 4 and the positive of the G4 bulb connected to pin 1 of the relay.

With the original 4.5v circuit powering the LEDS it will now be powering the reed relays instead and be able to power the higher voltage bulbs from an separate 12v power supply.

 

[Spanky]

Thanks. I plan to get a proper PCB made. Would Solid State Relays not be more appropriate?

 

[Funhouse71]

I don't see why solid state relays wouldn't work just apply my principle on how to wire it up.

 

[Spanky]

Thanks again. Forgive my ignorance, would this suffice? Panasonic AQV251G