Re: Breaker Panel Label Back Lights
Because of your remark I just remembered something about this. When I repopulated the PCBs with new LEDs I also replaced the resistors.
When you buy this package from Amazon: https://www.amazon.com/microtivity-IL142-Diffused-Blue-Resistors/dp/B0059H5Z5O/ref=sr_1_24?dchild=1&keywords=blue+led+5mm&qid=1596107237&sr=8-24
you get the LEDs with a resistor. If I remember correctly this was the actual package I bought. You will need three packages and have a lot of spares after installation. I replaced the existing resistors with the new ones. It will increase the voltage output for the regulator compared to no resistor and make it more stable.
Apparently these LEDs take 20 mA each. So two in series for every switch is still 20 mA. Multiply this by the number of panel switches which I think are 34. So, 34 x 20 = 680 mA. So at 500 mA they will receive about 15 mA.
I don't remember exactly but I think I was happy with this from brightness point of view. So I kept it at that as this will improve the life-span of the LEDs even more.