If your budget is limited, or you are trying to enter the solar field with a smaller system, then a pulse width modulation (PWM) controller is the best choice. The maximum solar input of the PWM controller is usually 25-50 volts DC, so the panels must be connected in parallel. The maximum efficiency of PWM controllers is 79% due to the way they regulate the power generated by solar panels.
The efficiency of the maximum power point tracking charge controller ( MPPT charge controller ) is about 90%. It will maximize the output of the solar system. The MPPT charge controller usually accepts 100-150V DC solar input. It will give you the option to connect the panels in series or in parallel. We recommend using the MPPT charge controller for series configuration because it is easier to install. Having an MPPT charge controller and connecting the panel in series will reduce the wiring resistance. A smaller resistance means that there can be a greater distance between your solar panel and the charge controller. If you are trying to set up the system and plan to make the distance between the solar panel and the charge controller greater than 30 feet, then you must use an MPPT charge controller.
What is the recommended component connection method for PWM and MPPT controllers?
Answer: The PWM controller is recommended to be installed in parallel; the MPPT controller is recommended to be installed in series, parallel or series-parallel.
Should I connect the solar panels in parallel or series?
If you have a PWM charge controller and plan to charge a 12V battery pack, you must connect the solar panels in parallel.
If you have an MPPT charge controller, you can connect the panels in series or parallel. To determine which setting is better, let's take a look at the following questions:
- What is the distance between your solar panel and the charge controller?
If the distance between the solar panel and the charge controller exceeds 20 -25 feet, we recommend that you connect the panels in series. When your panels are connected in series, the working voltages of the panels will be added together. If you connect two 100-watt panels in series and each output is 18V, you will end up with 200W (36V and 5.55A under optimal conditions). The higher voltage helps to eliminate the voltage drop caused by the large distance and allows the amperage to reach the controller effectively.
- Will your solar panel experience any type of continuous shadows throughout the day?
If your answer to this question is yes, we recommend that you connect the panels in parallel. When your panels are connected in parallel, you add the amperage together, but the voltage remains the same. For example, if you have two 100-watt solar panels, each panel will produce approximately 5.55A. Connecting these panels in parallel will generate 200 watts (18V and 11.1 A under optimal conditions).
- What type of battery pack do you want to charge: 12V or 24V?
If you want to charge a 24V battery pack", you must connect the panels in series to reach the charging voltage required to charge the 24V battery pack.
We hope this information will help you make wiring decisions. If you need any other information, please feel free to contact us.