IVT's 18318 - 20A MPPT solar charge controller belongs to the manufacturer's series of modern, microprocessor-controlled MPPT solar charge controllers, which were developed for charging lead-acid batteries in solar stand-alone systems. The MPPT (maximum power point tracker) enables you to make optimum usage of the solar power of your solar modules. The most efficient operating point of the solar modules changes due to factors such as exposure rate, temperature and the type of solar cells. This optimum operating point (MPP- maximum power point) is monitored constantly by the internal microprocessor of the solar controller and is controlled by the MPPT in such a way that your battery is always charged with maximum power.When the maximum charge voltage of your battery has been reached, the MPPT solar controller switches the charging current off. The microprocessor is also responsible for controlling all important protective functions. A load output to be switched by push-button enables you to switch on and off all consumers connected to the MPPT solar charge controller by the push of a button.Step-up functionThe MPPT solar controller is equipped with a step-up function, i.e. the solar controller charges even if the solar voltage is lower than the battery voltage. Here, the maximum charging current is 1A. Note: Please note that this function is not given if the solar voltage is lower than the solar controller’s own consumption. In this case, the solar controller switches to standby. (See explanation of standby function)Standby function When the solar charging power is lower than the solar controller’s own consumption, the standby function is automatically activated after 30 seconds. This may also occur when the module is connected to the solar controller for the first time. When the solar controller is in standby mode, all battery status LEDs (4, 5, 6) and the optional remote display are switched off. Now the solar controller checks in intervals of 11 minutes whether sufficient solar power is available. If yes, the solar controller switches to normal charging operation. Now one of the 3 battery status LEDs is on. The standby function may also be deactivated manually by pushing button 1 once. Deep discharge protection The solar controllers of the MPPT series are equipped with deep discharge protection, i.e. with battery voltage decreasing to 10.5V, the solar controller switches the load off automatically. As soon as the battery is recharged over the solar module, the load switches on automatically.Overcharge protection The MPPT solar controller stops the charging process reliably, when the final charging voltage is reached. This prevents the battery from being damaged by overcharging or heavy steaming. The final charging voltage is factory-preset to 14.1V at 22°C.Desulfation function (pulse charging) Following the regular main charging phase, the solar controller applies pulses to the battery. This causes sulfate layers in the battery to be dissolved which prolongs the battery lifetime significantly.Temperature protective circuit The MPPT solar controllers switch off the load current, when the temperature inside the device is too high. The load output continues to function. When the solar controller has cooled down to normal operating temperature, charging current is reconnected automatically.Reverse polarity protection The MPPT solar controllers are protected against incorrect connection to the battery. In case of incorrect connection to the battery, the red LED7 is on. Ensure correct polarity when connecting (LED7 is off). The solar controller is reset automatically and ready for use again.