Fortress Power Solo 6.5K 48V Non-Export Hybrid Inverter, 6.5kW Split/Single-Phase, Dual MPPT 10kW Solar Input, 140A Battery Charger, UL 1741

About The Fortress Power Solo 6.5K is a 48V non-export hybrid inverter

The Fortress Power Solo 6.5K is a 48V non-export hybrid inverter that delivers 6,500W of continuous split-phase 120/240Vac power. It is designed for residential backup power, off-grid systems, and self-consumption solar installations where grid export is not required or not permitted. This inverter combines a built-in 140A solar charge controller, dual MPPT inputs, and grid/generator input into a single compact unit, making it a straightforward option for homeowners and installers looking for an all-in-one solution without the complexity of stacking separate components.

The "non-export" designation means this inverter does not feed power back to the utility grid. It is built for systems that store solar energy in batteries and use it locally. This makes it a good fit for areas where net metering is unavailable, where utilities restrict or prohibit grid export, or where the homeowner simply wants to maximize self-consumption of their solar production. It also simplifies permitting in many jurisdictions since non-export systems often face fewer interconnection requirements.

Solar Input and Charge Controller

The Solo 6.5K has two independent MPPT (Maximum Power Point Tracker) channels, each rated for up to 5,000W of PV input, for a combined total of 10kW of solar capacity. Each MPPT accepts a maximum open circuit voltage of 550Vdc with an operating voltage range of 150-450Vdc, providing flexibility for a variety of string configurations. The maximum input short circuit current is 18A per MPPT. The built-in charge controller supports up to 140A of DC charging current from solar, which means batteries charge quickly even during partial sun conditions. MPPT tracking efficiency is rated at 99.9%, so very little of the available solar energy is wasted in the conversion process.

Grid and Generator Input

The Solo 6.5K accepts both grid and generator AC input with intelligent automatic switching. When grid or generator power is available, the inverter can charge the battery bank at up to 9,600W from the grid or 4,000W from a generator. The input phase voltage range is 65-140Vac per leg, and the bypass overload current is rated at 40A. The switching time between power sources is 10ms typical, which is fast enough to keep most electronics and networking equipment running without interruption.

For off-grid users with a backup generator, this means the inverter can automatically bring the generator online when battery SOC (State of Charge) drops to a user-defined level, charge the batteries, and then shut the generator back down. This extends the life of both the battery bank and the generator.

Battery Compatibility

The Solo 6.5K operates on a 48Vdc nominal battery bus with a voltage range of 40-60Vdc. It supports lithium batteries, lead-acid batteries, and user-defined battery types through its communication interfaces. The inverter communicates with battery management systems via RS485 and CAN bus, providing closed-loop monitoring of voltage, current, temperature, and SOC.

The Solo 6.5K pairs naturally with Fortress Power's own LFP battery lineup, including the eVault MAX, eFlex MAX, eForce, and eBoost systems. It is also compatible with third-party 48V battery banks.

Scalable to 39kW

A single Solo 6.5K provides 6,500W of continuous output, but the inverter supports parallel operation of up to six units for a combined output of 39kW. This makes the Solo 6.5K a scalable platform. A homeowner can start with one unit for essential loads and add more units as their energy needs grow or their budget allows. Three units can also be configured for three-phase 120Y/208V output.

Time-of-Use Scheduling

The inverter includes time-of-use (TOU) scheduling, which allows users to program charge and discharge cycles around their utility rate schedule. In areas with peak and off-peak electricity pricing, the inverter can charge batteries during low-rate periods and discharge them during high-rate periods, reducing overall electricity costs. This feature works in combination with solar charging to maximize the financial return on the system.

Monitoring and Communication

The Solo 6.5K uses the SOLARMAN platform for system monitoring, commissioning, and remote access. Through the SOLARMAN mobile app or web portal, homeowners and installers can view real-time system performance, historical data, and inverter status. The inverter includes RS485, CAN, USB, and dry contact interfaces as standard, with optional Wi-Fi and GPRS modules available for wireless connectivity.

Installation and Enclosure

This inverter is rated IP20 for indoor installation only. For outdoor installations, the Solo 6.5K can be mounted inside the Fortress Power FlexTower enclosure. The unit weighs 50.71 lbs and measures 27 x 16.1 x 6.1 inches, making it manageable for a single installer. Integrated AC and DC disconnects are built in, which simplifies the installation and reduces the need for external disconnect hardware. The operating temperature range is 14°F to 122°F (-10°C to 50°C), with derating beginning above 115°F (45°C). Fan cooling keeps internal components within operating temperature during sustained loads.

Output Quality

The Solo 6.5K produces a pure sine wave output at 120/240Vac in split-phase or 120Vac in single-phase configuration. The rated frequency is 50/60Hz (adjustable). Maximum inverter efficiency is 93%. Peak output reaches 13,000VA for surge loads like motor startup on well pumps, compressors, or power tools.

Certifications

The Solo 6.5K is certified to UL 1741 for safety, IEC 62109-1 and IEC 62109-2 for inverter safety standards, and FCC Part 15 Class B for electromagnetic compatibility. It is RoHS compliant.