Mrs Inor buys bunches of those solar motion lights whenever they are on sale at Amazon. She usually gets them for less than $2 each when they are on a Lightning Deal. So when they quit working we just throw it away and take out another.
https://www.amazon.com/Peasur-Outdoo...7&sr=8-16&th=1
They are a pretty sweet setup. I do not even mount them permanently; usually just wire them to a fence post with mechanics wire. They go on with any motion. So they keep a lot of the wildlife and wetbacks away at night. They give off a surprising amount of light for something so cheap. (I wouldn't want to read by them, but for what we use them for, they are perfect). Highly recommend.