Grid-Tied with Battery Backup 4320Watt
Residential Packaged System
Solar Panel Package (Photovoltaic) Tied into the Utility Grid with Battery Backup
4320W Peak Watts DC Solar Electric Panel System Featuring 24 Mitsubishi 180 Watt Solar Panels Outback FLEXware system with two GVFX3648.
Grid-Tie with Battery Backup
These full-service renewable energy systems give you all the benefits of utility innerconnection and net metering plus energy independence. With these grid-tie systems, backup AC power is made available in the even of a utility outage, providing reliable power and peace of mind. An average conversion efficiency of 89% – 91% using the California Energy Commission (CEC) test protocol provides greater savings and a shorter time period for system payback than previous designs.
Battery-backup grid-tie systems come with modules, array wiring, combiner boxes, roof mounting structures, inverters/control systems with all required over-current protection and disconnects. (Your specific installation or utility may require additional AC disconnects, which we can supply as needed). They require a 48 Volt battery bank to operate. The size of the battery determines the amount of back up power available during power failure.
1. Photovoltaic Modules (aka solar panels, solar electric panels)
The PV modules are the individual building blocks for providing power from the sun. They are typically made from silicon cells, glass, tedlar, and aluminum. PV modules can vary in type, size, shape, and color. The common nominal voltages for modules are 12V and 24V, but newer modules that are intended for grid tie systems, often now have much higher voltages to accommodate the voltage windows of grid tie inverters. Costs for PV modules are currently ranging between $4.40 and $5.40 USD per rated watt.
2. Racking/Mounting System for PV modules
The mounting system for the PV modules includes the hardware to permanently affix the array to either a roof, a pole, or the ground. These systems are typically made of aluminum and are customized to the mounting surface and the model of module used. It is important to consider distance from roof for flush-type roof mount installations. Restricting airflow under the modules results in higher module operating temperatures that reduce power output. With pole mounts wind loading must be considered and proper civil works must be done with the foundation for the pole as well as the possible addition of supplementary wind supports for the array frame. The cost of a mounting system can vary drastically based upon the number of modules and type of mount. The average cost is between $250 and $1000 USD.
3. Combiner Box
A combiner box is an electrical box where series strings of PV modules are then spliced in parallel. This is also the place where the PV series string fuses or circuit breakers are located. This allows the installer to bring the separate strings together and combine them into one positive and one negative conductor, change wire types and leave the area of the modules in conduit. They are usually outside and weather rated, so they can be right next to the array. Combiner boxes usually cost between $80 and $140 USD.
4. Charge Controller
A charge controller is a device that regulates the amount of current the PV modules feed into a battery bank. Their main function is to prevent over-charging of the batteries, but charge controllers also block reverse current from a battery bank from leaking backwards into the photovoltaic array. There are a few varieties of charge controllers, but the two main types are PWM (pulse width modulated) and MPPT (maximum power point tracking). PWM technology is older and more common on smaller solar arrays. With PWM, the controller is sized based on nominal PV voltage (which must match battery bank nominal voltage) and the total solar array output current. PWM controllers typically have two to three stages for battery charging and maintenance. MPPT controllers can typically take much higher voltages (but not lower) than the battery bank that they are charging. They “track” the performance of the solar array and can find the maximum power point from a module even when converting excess voltage to usable current. MPPT charge controllers can allow for a 10% to 25% increase in power sent to the batteries over a standard PWM controller. Charge controllers typically cost between $50 and $500 USD depending on size and type.
5. DC and AC Disconnects
The DC and AC disconnects are manual switch units that are capable of cutting off power to and from the inverter. Some inverters have disconnects integrated into the unit with switches, others can have them integrated into a power panel assembly, and some inverters leave you on your own to provide suitable disconnecting means. The disconnects are used by service personnel or authorized persons (fire/police/electric workers) to disable power from a renewable energy system (in this case PV) so that there are no live electrical parts associated with the inverter, and that no current is going to the grid that could harm utility employees in the event that they are working in your area. Homeowners or authorized personnel can use the disconnects to de-energize a system for maintenance or service. Disconnects can range in cost from $100 to $300 USD.
6. Grid Tie with Battery Backup Inverter
A grid tie with battery backup inverter takes current from batteries (DC) and turns it to alternating current (AC) to run any common loads like an off-grid inverter. Unlike an off-grid inverter, when there is an excess of current going to the batteries from solar or wind, the charge controller allows the inverter to sell the excess to the grid like a grid tie inverter instead of wasting the excess energy that the battery bank could not otherwise hold. Input voltages for these systems are usually 24V or 48V nominal. If there are no demands on the inverter (from AC loads pulling from the inverter /batteries) and the batteries are full because of this, then the inverter sells the extra energy that is made by the solar or wind system. When the power goes out, a grid tie with battery backup inverter disconnects from the grid, and supplies any loads tied to it from the existing battery bank, just like an off grid inverter. It will continue providing for those loads until it exhausts the energy stored in the battery bank. The inverter will not sell any power back until the grid returns to normal for five minutes straight under strict parameters. Grid tie with battery backup inverters typically cost between $1500 and $5000 USD.
Batteries store the energy in renewable energy systems. Batteries can come in different voltages, but the most common varieties are 6 volt and 12 volt. The three types of batteries that are most common to renewable energy systems are Flooded Lead Acid, Sealed Absorbed Glass Mat (AGM), and Sealed Gel Cell. Flooded lead acid batteries are the most cost effective variety of batteries. They require maintenance that involves monitoring voltage, adding water, and equalize charging. Flooded lead acid batteries vent hydrogen under heavy charging and they must be stored in a ventilated enclosure. Sealed AGM batteries do not require maintenance. Since they are sealed, they do not require watering, nor do they typically vent gasses. AGM batteries cost slightly more and are more sensitive to overcharging. Gel Cell batteries are also sealed and therefore do not require maintenance and they do not typically vent gasses. Gel batteries are the most expensive of the three most typical types. Depending upon size, batteries can cost anywhere from $20 to $1200 USD each.
8. Cables, Connectors and Brackets
Everything you need to connect all the pieces and parts together safely and securely!