MPPT Solar Charge Controller
Controllers 4830/4845 are 30/45 Amp 12/24/36/48 Volt Maximum Power Point Tracking (MPPT) photovoltaic (PV) battery charge controller. Through the use of patented MPPT technology, controllers can increase charge current up to 30% or more compared to conventional controllers. Controller 4830/4845's sophisticated three stage charge control system can be configured to optimize charge parameters to precise battery requirements based on battery electrolyte type, battery size in amp-hours, and battery temperature. The unit is fully protected against voltage transients, over temperature, over current and reverse battery and reverse PV connections. A manual equalize function is provided to periodically condition flooded lead-acid batteries. Controllers 4830/4845 also include an automatic current limit feature which allows use of the full 3045 Amp capability without worrying about overload or nuisance fuse blow from excessive current.
Solar controller 4830/4845 employs series pass Pulse Width Modulation (PWM) for voltage control. The multistage charge control system combined with precise PWM voltage control leads to superior charging and enhanced battery performance. To provide optimum charge control on installations where battery load varies widely during charge, controller 4830/4845 can interface to an external current shunt to provide optimal charge control. The PWM control system uses highly efficient and reliable power MOSFET transistors. The MOSFET's are turned on and off at high frequency to precisely control charge voltage and MPPT. The high reliability relays are used to disconnect the PV array at night to prevent unwanted current drain. Relays are used rather than blocking diodes for improved power conversion efficiency, current boost performance, and true reverse battery polarity protection in an MPPT controller. The relays are not stressed by functioning as part of the voltage control system and continually turning on and off as with other PV controllers. They simply turn on in the morning and off in the evening, and in this application have a life expectancy in excess of 105 operations.
Fully automatic temperature compensation of charge voltage is available as an option to further improve charge control and battery performance. The available battery temperature sensor is built for long term reliability. The sensor element is environmentally sealed and encapsulated into a copper lug which mounts directly to the battery terminal. A user friendly digital display is also available to monitor PV charge performance. The display may be provided in the 4830/4845 controller, as a remote panel, or both.
Maximum Power Point Tracking (MPPT)
The Maximum Power Point Tracking (MPPT) is an optimization method that is used in photovoltaic systems and solar modules and ensures that the operating point of the solar modules is shifted so that they always achieve the highest feed-in power. The MMP changes on the current irradiation intensities and operating temperature.
In order for a photovoltaic system to always achieve under the varying operating conditions the maximum sustainable yield, it is necessary that the solar generator is always working close to or exactly at the Maximum Power Point. This is ensured by an integrated MPP-Controller in the inverter that tracks the maximum operating point through the MPP tracking and the current operating point of the system is adjusted accordingly. Especially important is the MPP-Tracking in partial shading of solar modules. Here we recommend inverter whose MPP-Controller is equipped with a special tracking algorithm.
There are several inverters on the market and their efficiencies have some major differences. This is finally a decisive factor for the choice of the right inverter. Because not only the efficiency of the solar modules, and therefore their best possible functionality, is for the solar electricity output of importance, but also the operation of the inverter. Different inverters with the same Functionality can provide very different profits. If the result of an optimal functioning with an annual efficiency of 97-98 percent, so others can be only at 90 percent - under the same conditions.
These differences in the functionality are significant to the profitability and the function of a PV-system. A sample calculation shows that only three percent of performance difference in voltage transformer can effect about 1200 EUR revenue shortfall in 20 years at a power plant of 8 - 10 kWp .