Grid-Tied Inverters
| Advanced Energy Inverters (PV Powered) |
Wattage | CEC -Rated Efficiency | Price (US $) |
|---|---|---|---|
| PV Powered 2.0 Kw Inverter with disconnect (240V) | 2000 | 92% | 1772.24 |
| PV Powered 2.5 Kw Inverter with disconnect (240V) | 2500 | 94.5% | 1970.26 |
| PV Powered 3.0 Kw Inverter with disconnect (240V) | 3000 | 93.5% | 2140.86 |
| PV Powered 3.5 Kw Inverter with disconnect (240V) | 3500 | 95.5% | 2330.50 |
| PV Powered 4.8 Kw Inverter with disconnect (240V) | 4800 | 96% | 2867.42 |
| PV Powered 5.2 Kw Inverter with disconnect (240V) | 5200 | 96% | 3009.39 |
| Fronius Inverters |
Wattage | CEC-Rated Efficiency (240 volts) |
Price (US $) |
|---|---|---|---|
| Fronius IG 2000 Inverter | 2000 | 93.5% | 1284.64 |
| Fronius IG 3000 Inverter | 3000 | 94% | 1616.16 |
| Fronius IG Plus V 3.0 Inverter | 3000 | 95.5% | 2171.68 |
| Fronius IG Plus V 3.8 Inverter | 3800 | 95.5% | 2320.64 |
| Fronius IG Plus V 5.0 Inverter | 5000 | 95.5% | 2998.11 |
| Fronius IG Plus V 6.0 Inverter | 6000 | 96% | 3285.60 |
| Fronius IG Plus V 7.5 Inverter | 7500 | 95.5% | 3532.02 |
| Fronius IG Plus V 10.0-1 Inverter | 10,000 | 95.5% | 4510.30 |
| Fronius IG Plus V 11.4-1nverter | 11,400 | 95.5% | 5106.00 |
| Fronius IG Plus V 11.4-3 Inverter (3-phase) |
11,400 | 96% | 5106.00 |
| Fronius IG Plus V 12.0 (3-phase) |
12,000 | 96% (277 volts) | 5191.10 |
| SMA Sunny Boy Inverters |
Wattage | CEC-Rated Efficiency | Price (US $) |
|---|---|---|---|
| Sunny Boy SB700 Inverter with display | 700 | 91.5% | 861.00 |
| Sunny Boy 3000US Inverter with display | 3000 | 95% | 1549.80 |
| Sunny Boy 3800US Inverter with display | 3800 | 96% | 1911.41 |
| Sunny Boy 4000US Inverter with display | 4000 | 96% | 1911.41 |
| Sunny Boy 5000US Inverter with display | 5000 | 95.5% | 2496.89 |
| Sunny Boy 6000US Inverter with display | 6000 | 95.5% | 2651.88 |
| Sunny Boy 7000US Inverter with display | 7000 | 96% | 2867.13 |
| Sunny Boy 8000US Inverter with display | 8000 | 96% | 3123.12 |
| Sunny Boy High Frequency Inverter SB2000HFUS | 2000 | 95% | 1463.69 |
| Sunny Boy High Frequency Inverter SB2500HFUS | 2500 | 95% | 1536.02 |
| Sunny Boy High Frequency Inverter SB3000HFUS | 3000 | 95% | 1618.68 |
| Schneider Electric (Xantrex) |
Wattage | CEC-Rated Efficiency (240 volts) |
Price (US $) |
|---|---|---|---|
| Schneider Conext GT2.8 Inverter 208/240V | 2800 | 94 | 1505.28 |
| Schneider Conext GT3.3 Inverter 208/240V | 3300 | 95 | 1774.08 |
| Schneider Conext GT3.8 Inverter 208/240V | 3800 | 95 | 1899.52 |
Off-Grid and Battery-Based Inverters
| Outback Power Inverter | Cont. Watts |
Price (US $) |
|---|---|---|
| Outback GTFX2524 2.5 kw 24V Inverter | 2500 | 1698.10 |
| Outback GTFX3048 3.0 kw 24V Inverter | 3000 | 1698.10 |
| Outback GVFX3524 3.5 kw 24V Inverter | 3500 | 1841.46 |
| Outback GVFX3648 3.6 kw 24V Inverter | 3600 | 1841.46 |
| Outback FX2524T 2.5 kw 24V turbo inverter | 2500 | 1698.10 |
| Outback FX3048T 3.0 kw 48V turbo inverter | 3000 | 1698.10 |
| Outback VFX2812 2.8 kw 12V inverter | 2800 | 1841.46 |
| Outback VFX3648 3.6kw 48 V inverter | 3600 | 1841.46 |
| Schneider Electric Inverters (Xantrex) | Cont. Watts |
Price (US $) |
|---|---|---|
| Schneider Electric XW4024-120-240-60 Inverter | 4000 | 2806.08 |
| Schneider Electric XW4548-120-240-60 Inverter | 4500 | 2806.08 |
| Schneider Electric XW6048-120-240-60 Inverter | 6000 | 3196.80 |
| Schneider Electric XW Power Distribution Panel | 1075.20 | |
| Schneider Electric XW Connection Kit (for inv2) | 609.28 | |
| Schneider Electric XW Conduit Box | 188.80 | |
| Schneider Electric XW Auto Generator Start | 151.04 | |
| Schneider Electric XW System Control Panel | 226.56 | |
Grid-Tied Inverters
Inverters change direct current (DC) to alternating current (AC). Stand alone inverters can be used to convert DC, from a battery, to AC to run electronic equipment, motors, appliances, etc. Grid intertie inverters are used to convert the DC output of a photovoltaic module, a wind generator or a fuel cell to AC power that has the same phase angle as your electrical supplier. The energy goes back into your utility grid and your meter credits you with the amount of electricity you produce. Storage batteries are not needed, as all power produced is either used directly during production by the owner's electrical loads or is fed into the utility grid to be used elsewhere.
There are two major types of grid-tie inverters: string inverters and microinverters (such as the Enphase series). Most battery-less inverters (such as those in the tables below) are string inverters. The name string comes from the way the PV modules are wired together in series to achieve higher voltage. These inverters are designed to run at voltages up to 600 VDC. String wiring is faster to install, more efficient and allows the use of smaller gauge wire. DC voltage this high can be very dangerous so string inverters should usually be installed by qualified persons.
All grid-tie photovoltaic inverters use the utility company as a storage battery. When the sun shines, the electricity produced from the solar array powers onsite appliances via the inverter. If excess power is produced, the power is sent back to the utility company to run the meter backwards. Some utility companies credit the owner's electric bill and this is known as "net metering." Unfortunately, in many cases consumers are not reimbursed for excess power generated. Also, remember that grid-tied photovoltaic systems will not have power in the case of a utility outage; if the power goes down, a grid-tied inverter will go off as well, regardless of whether the sun is shining.
Off-Grid and Battery-Based Inverters
Off-grid, or battery-based inverters, convert DC power stored in batteries to AC power that is used by household appliances and other electrical loads. Select an inverter for the power system based on the maximum load it will be powering, AC output voltage required, input battery voltage and featured needed. High quality battery-based inverters are available in sizes from 120 watts, for powering notebook computers and fax machines from your car, to 60 kilowatts, for powering a commercial operation. The size of an inverter is measured by its maximum continuous output in watts. This rating must be larger than the total wattage of all the AC loads you plan to run at one time. (See system loads worksheet.)
Off-grid inverters are available with two basic power output waveforms: sine wave and modified sine wave (modified square wave). Sine wave inverters have a higher cost but they can operate almost anything that can be operated on utility power. The Outback and Xantrex XW inverters can be ganged together for up to 36 kW of output and can operate off-grid and grid-tied.
Dual Function Inverters
Using a dual-function inverter allows the inverter to sell excess power to the utility and also to maintain a battery bank for standby power in the event of a utility power failure. In a typical installation, the inverter is connected to a battery bank, a subpanel for critical loads that will be powered during a power outage and the building's load center. If the utility fails, the inverter will supply power to the loads from the battery. When the utility is available again, the inverter will switch back to the utility and recharge the batteries. If the batteries become fully charged by another power source, such as the photovoltaic modules, or a wind generator, excess power may be sold back to the utility in locations which are fortunate enough to allow net metering.
The Xantrex XW and the Outback GFX series inverters are primarily off-grid inverters that can function as an intertie inverter at the same time, but with a slightly lower efficiency than a battery-less inverter designed for grid-tie only. They are designed to provide battery backup power when the utility fails. The PV array charges the batteries through a charge controller. Once the batteries are full, excess power produced by the PV system is returned to the grid.
The SMA Sunny Island inverter is designed to work with a Sunny Boy inverter in an "AC-coupled" system to provide utility intertie with batter backup. In an AC-coupled system, the PV array is connected to a battery-less Sunny Boy inverter, just like a standard grid-tie system, except that the Sunny Boy's AC output goes to the critical loads panel subpanel connected to the AC output of the Sunny Island inverter. Normally, power produced by the grid-tie system passes through the Sunny Island and out to the grid. If the grid fails, power is drawn from the batteries to energize the subpanel. The Sunny Boy inverter can now re-activate and provide power from the PV array to help power loads and charge the batteries.
Output Voltage
Most of the battery-based inverters supply standard 120VAC/60Hz single-phase outputs. The SMA Sunny Island and Outback inverters can be stacked in pairs for 240VAC, such as is available from the utility companies. Pairs of Outback and Sunny Island inverters can also be wired in parallel to provide more output power at 120VAC single-phase, or 120/240VAC split-phase.
