RV solar systems are more than just panels on the roof. Any well designed RV solar system has a Charge Controller or Regulator as part of the system. It is the heart of the solar system. Without it, the batteries will not be properly charged and damage to the battery pack will occur. Or, at the very least, shorter battery life will result. One should NEVER EVER connect a solar panel directly to a battery pack without a controller.
MPPT or maximum power point tracking charge controllers are a relatively new product in the solar electricity game. They have a few distinct advantages over the older styles of charge controllers.
in addition to addressing the limitations of the early class of charge controllers, MPPT technology also cuts costs. Previous controllers were only designed with PV voltages in mind that would correspond to the battery bank. For example, a 36-cell "12-volt nominal" PV module was required for a 12-volt battery bank and a 144-cell array was necessary for a 48-volt battery. As module manufacturers have revamped their lines to elevate cell utilization for increased manufacturing efficiencies and reduced costs, 60-cell modules have become the industry norm whereas 36- and 72-cell modules have become increasingly rare and more costly per watt.
However, a designer using an MPPT controller can configure multiple 60-cell modules per string to charge a 12-, 24- or 48-volt battery. With higher voltage and fewer parallel connections, an installer has the advantage of saving costs on wiring and other expenses related to balance-of-system components.
Additionally, the latest charge controllers can add value with its ability to assess system performance and provide integrated communications capabilities for remote troubleshooting. Today's solar charge controllers have made a great deal of progress in efficiency and technology since the early 1980s and now capture greatest amount of solar power for every size of applications.
Maximum Power Point Tracking charge controllers can make your solar array produce up to 30 percent more, this is the original purpose to create the MPPT charge controller. All solar modules have a maximum power point voltage or SWEET SPOT. The SWEET SPOT is the voltage at which a solar module will make the most energy. An MPPT controller will connect to the solar module at the best voltage and then reduce the voltage to charge the battery. By connecting to the module at the mppt voltage, the output will be better by up to 30 percent.
It can make it possible to charge a lower voltage bank of batteries with a higher voltage solar module, before MPPT, customers would have to choose a charge controller and solar modules according to the voltage of the battery. If you had a 48 volt battery bank, you had to use a 48 volt solar module and a 48 volt charge controller. If you decided to decrease the battery bank voltage, you had to swap your solar module and your charge controller. Not anymore. MPPT charge controllers can take a higher voltage from the solar module and reduce it to charge the battery. As long as the solar module produces more voltage than the battery bank, the battery will be charged properly. If you decide to change the battery voltage later, the charge controller can be adjusted to the new voltage.
It also can allow you to transmit high voltage from your solar array ( keeping the amperage and wiring sizes lower) to your charge controller, and then reduce the voltage to the required battery voltage, another great feature of a lot of MPPT charge controllers is that they can accept voltages up to 250 volts. There is even at least one MPPT charge controller that can accept up to 600 volts DC and reduce it to charge a battery bank. Think about this. You have a long transmission distance between your solar array and your charge controller/battery bank. In the past you would have to transmit that electricity at 12, 24 or 48 volts. In a large array such as 10,000 watts, that would equate to 833 amps at 12 volts DC or 416 amps at 24 volts or 208 amps at 48 volts. Up the voltage to 600 and the amperage is only 16 amps. That equates to decreased size wiring and a lot less loss to resistance in the wire.
Solar modules must make high enough volts to charge a given battery. For example: A 12 volt battery bank requires at least 15 or 16 volts from a solar panel in order to charge. If the solar panel's voltage is lower than the battery, the battery will not charge. Even with MPPT, a solar panel's voltage must be higher to charge the battery. There is one new product being designed right now that will actually boost the voltage making it possible to charge a 24 volt battery with a 12 volt module, welcome to contact wellsee solar controller!