Why do I need a regulator?Updated 3 months ago
A 12V solar panel is designed to output at least enough voltage to charge a 12V battery under worst-case conditions (low light level, high temperature, etc). A 12V battery needs at least 13.6V to charge; therefore, a solar panel must output at least 13.6V under worst-case conditions.
This means that a 12V solar panel may output around 17V or more in optimal conditions. If you plug a solar panel generating 17V straight into your battery, it is easy to understand how this can cause damage.
Solar regulators are designed to accept the voltage from the solar panel and output a safe and useable voltage to charge a battery.