OutBack Power Brand Guide: FLEXmax Controllers, FlexPower Panels, and Radian Inverters
OutBack Power is an American manufacturer of off-grid and grid-interactive power systems, with a legacy spanning over two decades as the recognized standard for reliability in remote and mission-critical solar installations. Known for the FLEXmax charge controller line, FlexPower pre-wired system panels, and the Radian Series grid/hybrid inverter/charger, OutBack has built its reputation on rugged construction, advanced power management, and the ability to perform in the harshest environments. This guide covers OutBack Power's product lines, certifications, warranty terms, and technical specifications.
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Company Overview
OutBack Power is headquartered in Arlington, Washington (17825-59th Avenue NE, Suite B, Arlington, WA 98223), with a European office in Schwabach, Germany. Founded in the early 2000s, OutBack established itself during the formative years of the off-grid solar industry by producing inverter/chargers and charge controllers that could survive in extreme conditions—desert heat, arctic cold, high humidity, and corrosive salt air.
OutBack's market position is that of the off-grid legacy leader. The company's products are specified in remote telecom sites, off-grid homes, agricultural operations, microgrid installations, and backup power systems where failure is not an option. The Radian Series introduced Grid/Hybrid technology, enabling systems to operate in both grid-interactive and standalone modes, while the FlexPower platform brought pre-wired, pre-tested system integration to the off-grid market. OutBack's products are designed to be stacked and scaled, supporting systems from 4kW to 36kW+.
Current Product Lines
FLEXmax Charge Controllers
The FLEXmax line is OutBack's MPPT charge controller series, available in two models:
| Model | Max Output Current | Max PV Voc | Battery Voltages | Peak Efficiency |
|---|---|---|---|---|
| FLEXmax 80 (FM80-150VDC) | 80A @ 40°C | 150VDC (145V operating) | 12, 24, 36, 48, 60V | 97.5% (98.44% peak) |
| FLEXmax 60 (FM60-150VDC) | 60A @ 40°C | 150VDC (145V operating) | 12, 24, 36, 48, 60V | 98.1% (98.31% peak) |
Key FLEXmax features: advanced continuous MPPT tracking, full power output up to 40°C ambient, backlit 80-character LCD display (4 lines, 20 characters each), 128 days of data logging, voltage step-down capability (higher array voltage to lower battery voltage), manual and auto-equalization, programmable auxiliary control output, adjustable current limit (5-80A on FM80, 5-60A on FM60), battery temperature compensation with optional RTS, remote display via MATE3s, standby power consumption under 1W, and operating range of -40°C to 60°C.
FLEXmax 100 AFCI
The FLEXmax 100 is an upgraded model with 100A output current and integrated Arc Fault Circuit Interruption (AFCI). Designed for larger arrays and systems requiring NEC-compliant arc fault protection. Compatible with Radian Series systems through the GSLC load center.
Radian Series Inverter/Chargers
The Radian Series is OutBack's flagship grid/hybrid inverter/charger line:
| Model | Continuous Power | AC Output | DC Input | Efficiency |
|---|---|---|---|---|
| GS8048A | 8000VA | 120/240VAC, 60Hz | 48VDC (40-64V) | 92.5% (CEC weighted) |
| GS4048A | 4000VA | 120/240VAC, 60Hz | 48VDC (40-64V) | 92.5% (CEC weighted) |
| GS7048E | 7000VA | 230VAC, 50Hz | 48VDC (40-64V) | 92% |
| GS3548E | 3500VA | 230VAC, 50Hz | 48VDC (40-64V) | 92% |
Radian key features: seven operating modes including GridZero technology (balances stored energy, solar, and utility power), dual AC inputs (grid + generator with no external switching), modular stackable design (up to 9 inverters in 3-phase, 10 in grid-tied), Advanced Battery Charging (ABC) profiles for lithium-ion, field-upgradable software, unparalleled surge capability, and MATE3s system controller integration.
FXR / VFXR Series Inverter/Chargers
The FXR Series is the latest generation of OutBack's original FX inverter/charger platform, offering both off-grid and grid-tied functionality in a single unit. Available in sealed (FXR) and vented (VFXR) models with 12V, 24V, and 48V options. Features: die-cast aluminum chassis for harsh environments, stackable up to 9 units (3-phase) or 36kW (grid-tied), MATE3s and OPTICS RE integration. Models: FXR2012T, FXR2524T, FXR3048T (sealed); VFXR2812, VFXR3524, VFXR3648 (vented).
FlexPower Pre-Wired Systems
FlexPower systems are OutBack's pre-assembled, pre-wired, and pre-tested inverter system panels, designed for fast "mount, plug, and play" installation:
- FLEXpower Radian (FPR-8048A, FPR-4048A): 4kW or 8kW pre-wired Radian systems including FLEXmax 80 charge controller(s), MATE3 system display, FLEXnet DC monitor, HUB 10.3, surge protection, AC/DC wiring boxes, and remote temperature sensor.
- FLEXpower ONE FXR: Single inverter pre-wired system.
- FLEXpower TWO FXR: Dual inverter pre-wired system.
- FLEXpower THREE FXR: Triple inverter pre-wired system for three-phase applications.
GS Load Center (GSLC)
The GSLC is a pre-wired enclosure designed for Radian Series systems. Features: 175A inverter disconnects, GFDI, PV disconnects for two charge controllers, FLEXnet DC with 3 shunts, 120/240VAC inverter bypass, dual AC inputs. Max input: 600V, 500A. Dimensions: 17" x 16" x 8.5". UL 1741 and CSA C22.2 No. 107.1-01 listed.
MATE3s System Display
The MATE3s is OutBack's system controller and display, providing comprehensive monitoring and control of all connected OutBack devices. Features: LCD display, Ethernet connectivity for OPTICS RE remote monitoring, programming and configuration of inverters and charge controllers, and stacking management for multi-inverter systems.
OPTICS RE
OPTICS RE is OutBack's cloud-based remote monitoring and control platform. Features include: real-time system status, historical performance data, alarm notifications, remote configuration, and multi-site fleet management.
Additional Products
- FLEXnet DC: Battery monitoring system with 3 shunts for precise energy accounting.
- HUB 4 / HUB 10.3: Communication managers for connecting multiple OutBack devices to a MATE3s.
- EnergyCell Batteries: RE-series deep-cycle batteries (170RE, 200RE) designed for renewable energy cycling.
- PSX-240 Auto Transformer: For split-phase balancing and step-up/step-down voltage conversion.
Recent Releases (2025-2026)
OutBack Power has continued to develop the FLEXmax 100 AFCI charge controller, offering 100A output with integrated arc fault protection for larger arrays. The Radian Series has received firmware updates enhancing GridZero energy management and expanding lithium battery charging profiles. The FXR/VFXR Series continues to receive field-upgradable software updates. OutBack has enhanced OPTICS RE with improved alarm management and expanded device compatibility. The FLEXpower platform has been optimized for faster installation with improved pre-wiring and connector standardization.
Certifications & Listings
- UL 1741: FLEXmax charge controllers, Radian Series, FXR/VFXR Series, and GSLC listed to UL 1741 for US applications.
- CSA C22.2 No. 107.1: Canadian certification across charge controller, inverter, and enclosure lines.
- IEC 62109-1: International safety standard for Radian Series inverter/chargers.
- IEC 62477-1: Safety of power electronic converter systems.
- AS4777.2/AS4777.3: Australian grid connection standards.
- CE: European compliance (Radian international models).
- ROHS Compliant: Compliant per directive 2011/65/EU.
- NEC 690 Compliance: Integrated arc fault protection (FLEXmax 100), ground fault protection, and temperature compensation.
Warranty Terms
OutBack Power offers a standard 5-year warranty on charge controllers, inverter/chargers, and FlexPower systems, covering defects in materials and workmanship. An optional 10-year extended warranty is available for the Radian Series and FLEXmax controllers. The warranty covers repair or replacement at OutBack's option. OutBack products are known for service lives of 15-20+ years in the field, with many original FX-series inverters still operating after two decades of continuous use.
Popular Products at PES Supply
| Model | Category | Key Specs | Application |
|---|---|---|---|
| FLEXmax 80 (FM80-150VDC) | MPPT charge controller | 80A, 150V, 12-60V battery, 97.5% efficiency | Off-grid and battery-based PV systems |
| FLEXmax 60 (FM60-150VDC) | MPPT charge controller | 60A, 150V, 12-60V battery, 98.1% efficiency | Mid-size off-grid systems |
| Radian GS8048A | Grid/hybrid inverter/charger | 8000VA, 120/240VAC, 48V, 7 operating modes | Grid-interactive and off-grid residential/commercial |
| FLEXpower Radian FPR-8048A | Pre-wired system panel | 8kW, FM80, MATE3s, FLEXnet DC, HUB 10.3 | Complete off-grid/hybrid system |
| MATE3s | System display/controller | LCD, Ethernet, OPTICS RE, stacking management | System monitoring and control |
Technical Comparison: OutBack Power vs. Competitors
| Feature | OutBack (FM80) | MidNite Solar (Classic 150) | Victron (SmartSolar 150/70) |
|---|---|---|---|
| Max Output Current | 80A | 96A | 70A |
| Max Input Voltage | 150V | 150V (HyperVOC) | 150V |
| Battery Voltages | 12-60V | 12-72V | 12-48V |
| Peak Efficiency | 97.5% | ~97% | 98%+ |
| Data Logging | 128 days | 380 days | Cloud (VRM) |
| Built-in Display | Yes (80-char LCD) | Yes (graphical) | No (Bluetooth app) |
| Built-in AFCI | FM100 only | Yes (all Classics) | No |
| Pre-Wired System | FlexPower panels | E-Panel | No (DIY assembly) |
| Grid/Hybrid Inverter | Radian (7 modes, GridZero) | Rosie (7000W) | MultiPlus-II (ESS) |
| Remote Monitoring | OPTICS RE (paid) | My MidNite (free) | VRM portal (free) |
| Warranty | 5 years (10-year optional) | 5 years (extendable) | 5 years |
Installation Notes
Charge Controller Sizing
- FM80 (12V): 80A x 12V = 960W max array
- FM80 (24V): 80A x 24V = 1,920W max array
- FM80 (48V): 80A x 48V = 3,840W max array
- FM60 (48V): 60A x 48V = 2,880W max array
- FM100 (48V): 100A x 48V = 4,800W max array
OutBack recommends keeping array wattage at 80% of maximum for headroom during over-power events (cloud-edge effects, cold weather).
Wire Sizing & Overcurrent Protection
- FM80: Use minimum #4 AWG wire for output between controller and battery bus bar. Install OutBack PNL-80-DC circuit breaker for disconnect and overcurrent protection. Max PV array Isc: 64A under STC.
- FM60: Use OutBack PNL-60-AC/DC or PNL-80-DC circuit breakers. Max PV array Isc: 48A under STC.
- Torque all wire lugs and ground terminals to 4 Nm (35 in-lb).
- Current limit adjustable: 5-80A (FM80), 5-60A (FM60).
Environmental Ratings
- Operating temperature: -40°C to 60°C (full power -20°C to 45°C with passive cooling; -20°C to 55°C with Turbo Fan option).
- Environmental rating: Indoor Type 1.
- Conduit knockouts: One 1" on back, one 1" on left side, two 1" on bottom.
- Standby power consumption: less than 1W typical.
FlexPower System Installation
FlexPower systems are designed for wall mounting as a single pre-assembled unit. The system includes all AC and DC wiring, breakers, disconnects, and communication cables pre-wired and pre-tested at the factory. Installation requires: mounting the panel to the wall, connecting battery cables, connecting PV input, connecting AC input/output, and installing the MATE3s display. The pre-wired design eliminates the need for on-site assembly of individual components, reducing installation time from days to hours.
Radian System Configuration
Radian systems are configured through the MATE3s system controller, which provides a setup wizard for system commissioning. The seven operating modes can be selected and customized: Grid-Interactive, Grid-Tied, Mini Grid, Support, Backup, Off-Grid, and GridZero. GridZero technology provides precise balancing between stored energy, solar, and utility power, enabling smaller battery systems to perform like larger ones during peak demand. Multiple Radian units can be stacked for 3-phase or higher-power configurations using the HUB 10.3 communication manager.
String Sizing
OutBack provides a String Sizing Tool on their website for determining compatible PV string configurations. The tool accounts for: system DC voltage (12/24/48/60V), Voc temperature correction, maximum input current, and module specifications. The FM80's 150V absolute maximum (145V operating) must not be exceeded, with the controller shutting down at 100A output for over-current protection.
Frequently Asked Questions
1. What is OutBack's GridZero technology and when should I use it?
GridZero is one of the Radian's seven operating modes, designed to provide the perfect balance between utility power and stored renewable energy. It enables a smaller inverter and battery system to perform like a much larger one by blending grid power with stored energy to overcome surges and load spikes. GridZero is ideal for complex utility environments like California and Hawaii, where self-generation and self-consumption programs require precise energy management. It minimizes grid dependence while ensuring system stability.
2. What is the difference between the FM80 and FM60 charge controllers?
The FM80 outputs up to 80A continuous at 40°C ambient, while the FM60 outputs up to 60A. Both share the same 150V maximum input voltage, 12-60V battery support, 80-character LCD display, 128-day data logging, and voltage step-down capability. The FM80 is recommended for larger arrays (up to 4000W at 48V) while the FM60 is suitable for mid-size systems (up to 3000W at 48V). Both can be used with the MATE3s for remote monitoring via OPTICS RE.
3. Can OutBack systems be expanded after initial installation?
Yes. OutBack's modular, stackable design allows systems to grow over time. Radian inverters can be added for increased capacity (up to 9 units in 3-phase, 10 in grid-tied). Additional FLEXmax charge controllers can be added for larger arrays. The HUB 10.3 supports up to 10 connected devices. FlexPower systems can be expanded by adding GSLC enclosures and additional controllers. The MATE3s automatically recognizes new devices when they are connected.
4. How does the FLEXmax voltage step-down capability work?
The FLEXmax can step down from any acceptable array voltage to any battery voltage. For example, a 72VDC array can charge a 24V battery bank, or a 60VDC array can charge a 48V battery. This allows installers to design PV strings at higher voltages to reduce wire losses and use smaller gauge wire, while still charging lower-voltage battery banks. The controller automatically manages the voltage conversion through its MPPT DC-to-DC converter.
5. What warranty options does OutBack Power offer?
OutBack offers a standard 5-year warranty on all products including charge controllers, inverter/chargers, and FlexPower systems. An optional 10-year extended warranty is available for the Radian Series and FLEXmax controllers, providing double the standard coverage period. The warranty covers repair or replacement at OutBack's option. Products are known for their longevity, with many original FX-series inverters still operating after 20+ years of continuous service in demanding off-grid environments.
Shop OutBack Power at PES Supply
PES Supply carries the complete OutBack Power product line, including FLEXmax charge controllers, Radian Series inverter/chargers, FlexPower pre-wired systems, FXR/VFXR inverters, GSLC load centers, MATE3s controllers, and accessories. With 50,000+ SKUs from 169 authorized brands, we provide the off-grid and grid-hybrid power components you need. Orders typically arrive within 7-10 business days.
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Written by the PES Supply Editorial Team. Last updated July 2026.