6.7V input from the batteries, taken down to 5V with LM voltage regulator
The problem was that my motion activated lights actually used quite a bit of power when doing nothing, so their batteries would die after 1-3 months without them being used: This nice bright light has an RF receiver that needs to be powered all the time, sucking power:
This light is even worse, it uses more than 500mA when fully bright, and uses an infrared LED to detect hand swipes. That burns 3mA, killing batteries in less than a month:
My meter shows more than 0.5A when full bright:
Small show and tell video:
This is the ghetto end result in the shed, but it works :)
In the end, I did have to replace the LM voltage regulator with a better one from pololu, 2.5A 5V with less than 1mA quiet use. This allowed the batteries not to be used up into a voltage regulator doing nothing :) Then, I also had to put the voltage/amp display on an off switch, as it was using another 15mA just to display those values. Now, everything is happy :)