I wanted to make a mount bracket for several solar motion lights that I wanted to remove or change locations when traveling in my RV. I found that using magnets would be pretty useful and allow me to put in sun to charge and then on vehicle at night for security. The design was done in Fusion 360 and scaled to size using Slic3r.

Lights found during Amazon lightning sale for pretty cheap and are definitely bright:
Habor Solar Power Lights Bright 20 LED Motion Sensor Light Waterproof Exterior Security Lighting

Magnets are generic 1/2" x 3/8" found at hardware store and need to be epoxied into recess for best fit. Light is press fit and stays secure without needing machine screws.