Installing a controller prevents damage caused by overcharging the battery and current backflow to the solar panel. A solar charge controller is an important component of a solar panel system that ensures that the batteries in the system are maintained at the proper charge rate and. To know if a particular solar power system needs a charge controller, we need to calculate it in a scientifically safe way: take the amp-hour capacity of the batteries in the power system and divide it by the maximum power amp rating of the solar panels. If this comes out to be greater than 200. Why do solar panels need controllers? 1. Solar panels require controllers to ensure efficient energy management, optimize output, and safeguard against potential damage, 2. That's plenty for small off-grid systems, but when you plan your setup, think about how many panels you need to cover your energy usage. For example if you have a.