The amount of time it takes for solar panels to charge a well pump's battery is dependent on the solar panel efficiency and the battery maintenance. Solar panel efficiency refers to the amount of sunlight that is converted into electricity, and it can vary depending on the quality of the solar panels used. The battery maintenance is also essential for the charging process as a well-maintained battery can store more energy and charge faster. In recent years, the solar industry has made significant advancements in solar panel efficiency and battery technology, resulting in faster charging times. However, it is recommended to consult the manufacturer's specifications and guidelines for the specific solar pump and battery system being used to determine the estimated charging time.