Best off-grid inverters
Off-grid Inverters explained
Modern off-grid solar systems use advanced inverters to manage batteries, solar, and backup AC power sources such as generators. The off-grid inverter, often called an inverter-charger, is the heart and brain of an off-grid system. Its primary job is to supply pure sine wave AC power, and it must be able to meet the power requirements of the appliances under all conditions. Off-grid (multi-mode) inverters are the central energy management system and can be either AC-coupled with solar inverters or DC-coupled with MPPT solar charge controllers.
How to choose a reliable off-grid inverter?
When designing an off-grid power system, the inverter must be adequately sized and selected according to the appliances it will be running. Some equipment, such as water pumps, fridge compressors and air-conditioning units, require very high surge (peak) power during startup, and this is where many cheaper inverters can fail. If multiple appliances are running simultaneously, the inverter must also be able to supply continuous power under all conditions, including higher temperatures. If high temperatures and high loads are common, the inverter must be sized correctly to account for temperature de-rating. Again, this is where cheaper (transformerless) inverters can often trip, especially during high summer temperatures. Learn more in our technical guide to selecting an off-grid inverter.
Best off-grid inverters for home use
Here is our list of the leading off-grid inverters on the market based on reliability, service, continuous and peak (surge) power rating, energy management software, AC source control, flexibility and remote monitoring.
Selectronic - SP PRO series (Australia)
Victron Energy - Multiplus II or Quattro (Netherlands)
Outback Power - Radian series (USA)
SMA - Sunny Island series (Germany)
Schneider Electric - XW Pro (Italy)
Sol-Ark 12K - 15K hybrid & Deye - SUN 8K hybrid (China)
Some of the best off-grid inverters - SMA Sunny Island, Schneider Electric XW Pro, Victron Multiplus II, Selectronic SP PRO, and Outback Radian series from the US.
These inverters are all available in various power ratings (kW) to suit different applications depending on the continuous and peak power requirements. In addition, the top 5 inverters can be AC or DC-coupled using compatible solar inverters or solar charge controllers.
For a direct comparison, see our full list of the leading off-grid inverters.
Inverter cost and power ratings
Off-grid Inverters are available in a wide range of sizes from 2.4kW up to 20kW and can be connected in parallel or three-phase configurations for even greater power requirements. Naturally, these powerful inverters are much more expensive than standard grid-connected solar inverters or compact all-in-one hybrid inverters. They can cost anywhere from $1400 for a small 2.4kW unit to $9000 for a large 15kW inverter, depending on the power rating.
Surge Power Rating - Transformers
High-quality off-grid inverters use large, heavy-duty transformers to handle high surge (startup) loads without overheating and tripping off. Generally, the best off-grid inverters with the highest surge power ratings contain large toroidal core transformers. These high-quality transformers have very low magnetic flux leakage and high inductance, resulting in increased operating efficiency, and generally have a very long lifespan. The inverters from Selectronic, SMA, Schnieder Electric, and Victron all contain large, powerful toroidal core transformers.
Off-grid inverter power comparison chart - Continuous and peak surge power ratings shown
Most off-grid inverters can supply double or more of the continuous rating for a short time to handle surge power spikes from motors, compressors, pumps, etc. The surge rating is critical for off-grid systems to operate under various load conditions without tripping out or shutting down unexpectedly. Note the output power is limited after continuous high loads and under high ambient temperatures. For more detailed information about selecting off-grid and hybrid inverters, see our Technical guide to sizing hybrid inverters and off-grid power systems.
Control software & monitoring
The off-grid inverter is generally the heart and brain of an off-grid power system. No matter how good the hardware and build quality are, if the control software is problematic and unreliable, it will affect the off-grid system's performance and reliability. The best off-grid inverters can be programmed to manage multiple energy sources in various configurations, including AC and DC-coupled solar, backup generators and other AC sources. Backup generator monitoring and remote control are essential, and the inverter must be able to remotely start and synchronise with a backup generator to charge the battery and power AC loads simultaneously.
System monitoring and remote control are also essential, as they allow access in case of a system shutdown or issue. This enables off-grid professionals to remotely troubleshoot any issues and view the operating history to help diagnose any problems.
Selectronic SP PRO
The SP PRO inverter chargers from Selectronic, based in Australia, feature an extremely high 30-minute power rating and an impressive 2.5x peak/surge power rating thanks to the heavy-duty toroidal core transformers. They also feature many control methods, including relays and digital inputs and outputs, which can be configured for load management or generator control. However, it’s not just hardware that’s impressive; the SP PRO also features possibly the industry's most advanced energy management software.
However, premium quality comes at a premium price, and the SP PRO inverters are one of the more expensive options available. Although, considering the high cost of off-grid systems, paying a little more is well worth the power and features needed for a reliable off-grid system. The impressive features, high performance, and a 10-year warranty place the SP PRO at the top of our list.
See the detailed Selectronic SP PRO review.
SP PRO Basic Specifications
Type: Inverter-charger (Multi-mode & bidirectional)
Use: Solar storage, back-up (UPS), off-grid
Sizes available (power output): 3.0kW, 4.5kW, 5.0kW, 7.5kW, 15kW, 20kW
Pass through power: 15kW (63A) built-in (28kW external contactor)
Compatible Battery types: Lead-acid, lithium-ion.
Battery System Voltages: 24V, 48V, 120V
SP PRO Features
63A pass-through power rating (15kW AC) or 125A (30kW)
Very high surge power output (2.5 x rated continuous power)
Battery temperature monitoring for longer battery life (lead-acid)
Battery sense monitoring and a mid-string sensor for precise battery charging
Managed AC-coupling with FIMER, Fronius, and Select-Sun solar inverters
Powerful software package with remote access and monitoring.
Unique pre-charge feature for safer startup
Compatible with many popular lithium battery systems
Generator auto start, control and monitoring
AC / DC-coupling capability
Parallel and 3-phase capability
Disadvantages
Full off-grid capability when used with Selectronic-certified (Scert) Fronius or Fimer solar inverters
An additional AC input contactor is required if used with dual AC sources.
Additional Select-live unit required for remote monitoring and setup.
Price bracket – From AU$5000 (4.5kW)
Download the Selectronic SP PRO series datasheet.
Selectronic 3-phase off-grid system with AC and DC coupled solar - System by Transfer Solar
2. Victron MultiPlus 2
Victron Energy, based in the Netherlands, is a well-known, international, high-quality manufacturer with a comprehensive product range, including battery chargers, sinewave inverters, inverters-chargers, DC/DC converters, transfer switches, battery monitors, charge controllers and more. Victron offers the most cost-effective range of multi-mode inverters with a vast range of sizes, including the new MultiPlus II inverters-chargers from 800W to 15,000W (15kVA). Victron is an excellent, lower-cost option for many applications, especially for DC-coupled systems. The Victron remote system options are highly advanced and offer complete remote access and control and some powerful monitoring features. Victron products are also simple to set up and offer various add-ons and configuration options.
See the full Victron Energy Review.
Victron Basic Specifications
Type: Inverter-charger (Multi-mode & bidirectional)
Use: Solar storage, back-up (UPS), off-grid
Sizes available (power output): 1.6kW, 2.4kW, 4.0kW, 6.5kW, 8.0kW, 12kW (15kVA)
Pass-through power: 3.6kW - 23kW (100A) models available.
Compatible Battery types: Lead-acid, lithium-ion, Redox Flow battery
Battery System Voltage: 12V, 24V, 48V
Victron Multiplus Features
Economical Inverter-charger option
Med-High surge power output
High pass-through power capability
Battery temperature monitoring for longer battery life
Generator auto-start and monitoring available
AC coupling with Fronius, SMA, SolarEdge, and some Delta solar inverters
Dual AC outputs for non-essential loads (high-power units only)
Programmable software with remote access and Wi-Fi app
3-phase capability + parallel for higher power output
Disadvantages
Victron size the inverters in kVA, not kW (ref datasheet)
Full capability only when used with Victron charge controllers and Cerbo GX
Price bracket – from AUD$1600 (2.4kW), US$1100 (2.4kW)
Download the detailed Victron Multiplus 2 inverter datasheet.
Off-grid 3-phase Victron system using three Multiplus 2 5000VA inverters AC-coupled with a Fronius Symo solar inverter. System by Harpoon Electrics and Transfer Solar
24V DC coupled off-grid solar system with 2 x Victron Bluesolar charge controllers, 2.4kW solar array and Victron Phoenix 2.4kW battery inverter.
3. Outback Power Radian A-Series
Best off-grid inverter - Split-phase, North America
Founded in 2001 by three power systems design engineers, Outback Power has become one of North America's leading manufacturers of off-grid power systems. The company produces an advanced range of inverter-chargers designed for off-grid residential and commercial installations, along with the highly regarded Flexmax range of MPPT solar charge controllers. In addition to the popular FXR & vented VFXR series designed for off-grid use, the Radian series of bi-directional inverter-chargers were developed for advanced hybrid (grid-connected) energy storage systems and off-grid use.
Outback Basic specifications
Type: Inverter-charger (DC-coupled)
Use: Solar storage, back-up (UPS), off-grid
A-series sizes available (power output): 8kVA, 4kVA
Pass-through power: 50A at 120V/240V
Compatible Battery types: Lead-acid or lithium-ion
Battery System Voltage: 48V
Outback Radian Features
Outback Power FLEXpower systems - Pre-Wired solar Inverter Systems
Two split-phase models for 120VAC / 230VAC
High surge power output (2 x Power rating)
Dual AC inputs for Grid and Generator
Pass through power capability
Battery temperature monitoring for longer battery life
Generator auto-start and monitoring
Programmable software with remote access.
Up to 10 units in parallel for larger-scale systems
Radian GS Load centre (optional) for easy setup
AC-coupling using frequency shifting
Disadvantages
Inverters sized in kVA, not kW (ref datasheet)
Mate3 is required for full remote control and monitoring
Price bracket – from US$4000 (8kVA)
Download the Outback Radian A-Series datasheet.
4. SMA Sunny Island
SMA Solar Technology is a leading German solar energy equipment supplier founded in 1981 and is one of the world's largest manufacturers of solar inverters. The well-regarded Suny Island inverters are proven performers in harsh outdoor environments, particularly sub-zero temperatures. It’s also one of the only off-grid inverter chargers with an IP54 weather rating, enabling it to be installed in semi-exposed locations.
See the full SMA inverter Review.
SMA Basic specifications
Type: Inverter-charger (Multi-mode & bidirectional)
Use: Solar storage, back-up (UPS), off-grid
Sizes available (power output): 3.3kW, 4.6kW, 6.0kW
Pass-through power: 11.5kW
Compatible Battery types: Lead-acid, lithium-ion (refer to manufacturer)
Battery System Voltage: 48V
SMA Sunny Island Features
High pass-through power capability
High surge power output
Battery temperature monitoring for longer battery life
Powerful software package with remote monitoring
Generator auto start and monitoring (optional)
Dual AC inputs (grid and generator)
Excellent IP54 weather rating
AC / DC-coupling capability
3-phase capability + parallel for higher output
Disadvantages
Full capability when used with SMA or compatible solar inverters
External automatic transfer switch required to enable battery backup (hybrid systems)
When configured as a hybrid inverter, grid isolation (backup mode) is not instantaneous - 2-3 sec delay.
Price bracket – From AU$3800, US$2900
Download the detailed SMA Sunny Island datasheet.
Off-grid solar power system using a SMA sunny Island inverter/charger coupled with a Sunny boy solar inverter - System designed and installed by Off-grid Energy Australia.
5. Schneider Electric XW Pro
Schneider Electric is a well-known European corporation and an industry leader in electrical product development. The company is focused on designing and developing products for solar power conversion. They offer a range of high-quality inverters designed for off-grid and hybrid (grid-tie) applications, including the compact SW range and powerful XW Pro series described below.
XW Pro Basic specifications
Type: Inverter-charger (Multi-mode & bidirectional)
Use: Solar storage, back-up (UPS), off-grid
Sizes available XW Pro (power output): 5.5kW, 6.8kW
Pass-through power: 14kW (60A)
Compatible Battery types: Lead-acid, Lithium-ion (XW Pro only)
Battery System Voltage: 48V
XW Pro Features
High surge power output
Very high pass-through power capability
Battery temperature monitoring for longer battery life
Generator auto-start and monitoring (optional)
Dual AC inputs (grid and generator)
Programmable software with remote access
AC / DC-coupling capability
3-phase capability + parallel for higher output
Disadvantages
Full capability only when used with Schneider DC charge controllers.
No built-in battery state of charge (SOC) control system
Inverter can be difficult to configure for hybrid self-use installations
Price bracket – From AU$4000, US$3000
Download the detailed Schneider Electric XW Pro datasheet.
6. Sol-Ark 12K & 15K (Deye)
Sol-Ark is a relatively new US-based company that distributes an all-in-one hybrid/off-grid inverter manufactured by Deye Inverter Technology Co. The Sol-Ark inverter is available in two varieties, a 12K and a 15K model. It has been customised to suit the US market with many features, including ground-fault, arc-fault and lightning protection built-in, an integrated load centre with DC and AC isolators, and remote access, including monitoring. While feature-packed, it does have some compromises; the Sol-Ark inverter is transformerless, meaning it does not contain a toroidal core transformer. This common hybrid inverter design typically results in a limited surge power output and may struggle to power large inductive loads such as pumps and compressors. However, Sol-Ark (Deye) has engineered a large rear heat sink and cooling system, enabling a high surge power output.
Note the real-world loads (a combination of inductive and basic resistive or heating loads) are about 20% lower than the specifications listed. Each 120V leg is also limited to 4.8kW (12K model) & 6kW (15K model), so the loads must be managed and balanced accordingly.
Sol-Ark Basic specifications
Type: Hybrid Multi-mode Inverter (All-in-one unit)
Use: Solar storage, backup (UPS), Off-grid
Power rating 12K (9kW continuous): 4.8kW per leg/Phase (120V)
Power rating 15K (12kW continuous): 6kW per leg/Phase (120V)
Compatible Battery types: Lead-acid or lithium-ion
Battery System Voltage: 48V
Sol-Ark Features
All-in-one inverter with integrated dual MPPTs
Max Solar PV input 13kW (12K unit) and 19.5kW (15K unit)
Split phase - 120VAC or 240VAC
200A pass-through power rating (15K)
Higher power output available with parallel configuration
Inbuilt Ground-fault and Arc fault detection (GFD)
Inbuilt lightning protection (PV)
Integrated battery DC isolator and AC source/load isolator
Generator auto-start and monitoring built-in
Programmable software with remote access.
Colour touch-screen display
Disadvantages
Transformerless Inverter with limited surge power rating
Power is split between each leg - 50% per leg when powering 120V loads
Unbalanced loads on individual phases (legs) can limit performance.
Sol-Ark Price bracket – 12K from US$6800, 15K from $8200
Download the Sol-Ark 12K datasheet or the Sol-Ark 15K datasheet.
Deye SUN Inverters
The Deye Inverter Technology Company manufactures a range of inverters designed for hybrid and off-grid applications at a very affordable price. The Deye SUN-SG hybrid inverters are available in sizes from 3kW to 16kW in single-phase and 3-phase varieties. All Deye Hybrid inverters are built on a transformerless architecture, which does not contain toroidal core transformers. This standard hybrid inverter design results in a limited surge power output. However, Deye has engineered a large heat sink and fan-forced cooling system, enabling a surprisingly high surge power rating.
Features include a colour touch-screen display, generator auto-start control, and dual AC inputs for a grid supply and backup generator. While packed with features, the MPPT operating voltage is limited to 150V - 425V, and the maximum PV (Voc) voltage is a little low at only 500V on the single-phase models.
See more detailed information in the Deye Hybrid inverter review in our Forum.
Deye SUN-8K Basic specifications
Type: Hybrid Multi-mode Inverter (All-in-one unit)
Use: Solar storage, backup (UPS), Off-grid
Power rating (continuous output): 8kW
Compatible Battery types: Lead-acid or lithium-ion
Battery System Voltage: 48V
Deye SUN-8K Features
Integrated dual MPPTs - Max PV 10.4kW combined
50A pass-through power rating (12kW)
Higher power output available with parallel configuration
Inbuilt Ground-fault and Arc fault detection (GFD)
Integrated PV DC isolator
Generator auto-start and monitoring built-in
Programmable software with remote access
Colour touch-screen display
Disadvantages
Transformerless Inverter with limited surge power rating
The LCD user interface is not very intuitive, especially the generator settings
Remote monitoring software is challenging to set up and use
Deye SUN Price bracket – from AU$3000 US$2000
Download the detailed Deye SUN-8K datasheet.
Grid Interactive off-grid inverters
Most modern off-grid inverters can operate in on-grid (hybrid) or off-grid modes and can be used to build AC or DC-coupled solar systems. Different terminology is often used to describe these inverters due to the various applications and designs; this includes the term multi-mode inverter and, more recently, grid-interactive inverter due to the ability to synchronise with the grid and export or import energy. A common term is inverter-charger, as most modern off-grid inverters have integrated chargers.
Standard terms used to describe modern multi-mode / off-grid inverters
Multi-mode inverter - On-grid and off-grid modes
Grid-interactive inverter - Similar to a common hybrid inverter
Inverter-charger - Combination inverter and charger
Grid-interactive inverters contain an internal grid isolator (transfer switch), which enables the system to isolate from the grid during a blackout, known as islanding. Standard (all-in-one) hybrid inverters can also island and operate in off-grid mode, but they do not feature backup generator control and are not designed for continuous off-grid use. However, the Deye Hybrid inverter is one of the few exceptions.
Multi-mode inverters function much like simple battery inverters but also control grid connection and can be set up to start and run a backup generator automatically. In addition, these inverters can handle very high surge loads and pass-through additional power directly from the grid if the batteries are low or the load is very high. This pass-through power capability has many advantages, including the ability to power an entire home without the need to separate essential and non-essential loads or circuits.
Off-grid AC-coupled solar
For off-grid installations, it is critical the solar inverter is compatible with the inverter-charger to optimise battery charging; for example, when the battery is full and the loads are low, the solar output must be ramped down or managed by the (master) inverter-charger to prevent overcharging and damaging the battery system. SMA, Victron, and Outback Power use what is known as ‘frequency ramping’ to achieve this, which works but is not ideal. The most accurate method is direct communication control - for more detail, see our technical guide to designing off-grid power systems.
Solar questions?
Visit our community discussion about off-grid systems in our solar info forum.
