How long it takes to charge a battery with solar panels depends on various factors, including the battery's capacity, the power of the solar panels, the availability of sunlight, and any limitations in the charging control.

In general, the charging time can vary from a few hours to a whole day. The power of the solar panels, expressed in watt-peak (Wp), determines how much energy can be generated per hour. The higher the power of the solar panels, the faster the battery can be charged.

Additionally, the capacity of the battery plays a role. A larger battery capacity requires more time to fully charge. As a rule of thumb, you can assume it may take about 4-8 hours to charge a battery of average capacity using solar panels, but this can vary depending on the circumstances.

It's important to mention that solar panels don't always produce maximum energy. The yield of solar panels can vary depending on factors such as the intensity of the sunlight, the angle and orientation of the panels, weather conditions, and any shading. This can affect the charging time.

To get an accurate estimate of the charging time for a specific battery with solar panels, it is advisable to consult the technical specifications of the solar panels and the battery and if necessary, contact the manufacturer or a professional installer. They can assist you in determining the expected charging time based on the specific conditions of your system.