TWTADE Photoelectric Switch DC 12V 24V 36V 48V Control Light Auto ON Off (DC 8-50V) Dusk to Dawn Photocell Switch Hard-Wired Post Eye with Sensor H-NK-BB/F 50

It works well with 12-24V systems.

This dusk/dawn photo switch is the most confusing device I have encountered in a long while. Do not make any assumptions based on the color of the wires.The key thing to realize is that the middle (white) wire is a common POSITIVE. Connect this to the battery POSITIVE and also the light bulb POSITIVE.Next, connect the black wire to the battery NEGATIVE. The switch is now supplied with power, via the white (+) and black (-) battery connections.Finally connect the red line to the light bulb NEGATIVE.Yeah, the weird choice of wire colors makes this extremely confusing, but the above wiring works.BTW, it takes about 10 seconds for the switch to change state. Bright light will turn the lamp OFF, and darkness will turn the lamp ON.