The best solar-powered security camera placement is where the device receives the most sunlight and provides the best coverage. 

For a location with limited sun exposure, install the camera on a south-facing wall to receive at least 6 hours of sunlight every day. 

You should also install the camera high on the wall so intruders cannot easily reach to remove it. 

A small security camera is also more likely to go unnoticed by intruders.