The first way to do this is the easiest: first, charge the deep cycle batteries within your solar battery bank fully. Next, check the voltage of each battery using a multimeter and make a note of each level, then let them sit without a connection to any solar panel for a few days.
Solar battery charge is measured in terms of state-of-charge (SOC) – otherwise known as the voltage within the battery. If you want to know how to check what charge your solar battery has, just keep reading! What is the state-of-charge of a battery?
You can check if your solar panel is charging a battery by using a multimeter. Connect the probes to the positive and negative wires from the solar panel and set the multimeter to the direct current voltage setting. If the multimeter shows a reading around 12-20v during peak sunlight times, the solar panel is working and charging the battery.
Consider a scenario where you have a 200W solar panel with a working voltage of 20V and an amperage of 10A. To charge a 12V battery system, you’re going to need a charge controller to step down the voltage and regulate the current to prevent overcharging.
Solar panels charge deep cycle batteries through the use of a solar charge controller. The controller ensures that the maximum possible output of the solar panels is put into the batteries without being overcharged. A solar battery bank will take in an unusually high voltage when it is first being charged since the battery SOC is at its lowest.
Generally, a solar panel that provides 1 amp of electrical energy will fully charge a battery in 5 to 8 hours in full sunshine, but this time can be increased as the angle of the sun changes or if it becomes overcast. How do I know if my solar panel is charging?