The solar light batteries should be maintained by regularly checking their status. Firstly, you will need to check it every several months because solar street lights are likely to be stolen. Secondly, you should check if the solar light batteries work as normal and change them over time. You can do this by checking the signal light on the controller. And if the lights start lighting for fewer hours, remember to test if the capacity of the battery is enough or not.
More reading: Solar Street Light Battery: What to Know And How to Choose
