The solar controller is called the solar charge and discharge controller, it is a device installed between the solar panel and the battery which regulates and controls the charging and discharging conditions of the battery. Solar charge controller achieves this by managing the current and voltage flowing from the solar panel to the battery, so that the off-grid solar system can operate efficiently. It is the core control part of the entire photovoltaic power supply system.
The function of the solar charge controller is to regulate the charging and discharging of the battery, ensuring its stable operation.
- The electricity generated by the solar panel is affected by light intensity, resulting in unstable voltage. This unstable voltage can harm the battery. The solar panel charge controller reduces the charging voltage to ensure the battery's safety when the charging voltage is higher than the battery's working voltage.
- Additionally, the solar panel charge controller prevents overcharging and discharging. Once the battery is full, the controller slows down the charging speed to avoid damage from overcharging.
- Solar charge controllers can also prevent batteries from discharging in reverse to the solar panels.
Almost all solar energy systems that use batteries require a solar charge controller. But that's not always the case. Generally speaking, a solar charge controller is not necessary for small maintenance or trickle charge panels, such as 1 to 5-watt panels.
When choosing a solar charge controller, there are 2 factors that need to be considered:
- the rated voltage of the battery
- the maximum output current of the solar panel
The voltage of the controller should be the same as the voltage of the battery. For example, if the battery is 12V, it is necessary to select a 12V solar charge controller. BougeRV solar charge controller has good compatibility, it recognizes battery voltage automatically and can be used for charging batteries with 12V/24V/36V/48V.
The current rating of the solar charge controller typically ranges from 10A to 60A or more. It needs to match the maximum current of the solar panel. And it would be safer if you increased the margin by 25%.
If you choose the BougeRVsolar charge controller, you only need to consider the impact of the output current of the solar panel. If the rated voltage of the solar panel is 12V, then the size of the required controller can be calculated using the following formula:
Therefore, for a 400-watt solar panel, if your battery voltage is 12V, you can choose a 40Amp solar charge controller. If your battery voltage is 24V, you can choose a 20Amp controller.
In addition, for a 400W solar panel, it is recommended to use an MPPT solar charge controller because it enables the system to charge the battery at maximum power output.
When you increase the charging current by using multiple solar charge controllers at the same time, then you only need to connect each controller in parallel. This way, the charging voltage can meet the battery's requirements, and the increased current can charge the solar battery faster.
In addition, we recommend the use of MPPT solar charge controller, because the MPPT controller is capable of detecting the generation voltage of the solar panels in real time and tracking the highest voltage-current value (VI) to enable the system to charge the battery with maximum power output.