The SunGoldPower Freedom 12K-B (model FR12K-B) is a 12kW, 48V all-in-one off-grid solar inverter with selectable 120V single-phase or 120/240V split-phase output, two independent MPPT solar inputs, and a built-in battery charger. It combines a pure sine wave inverter, dual solar charge controllers, and a utility/generator charger in one wall-mounted unit, sized for homes, cabins, farms, workshops, and light-commercial backup-power systems.

At a glance: 12,000W continuous / up to 24,000W peak · 120/240V split-phase or 120V single-phase · 13,200W dual MPPT (500VDC max) · 48V battery bank · solar + utility + generator charging · up to 6 units in parallel (72kW) · IP20 indoor · Wi-Fi logger included.

• 12,000W continuous pure sine wave output, with up to 24,000W peak for brief motor and compressor startup surges.
• 120/240V split-phase (or 120V single-phase) output to run both 120V circuits and 240V appliances such as well pumps and dryers.
• Dual MPPT, up to 13,200W PV (6,600W per channel, 500VDC max) for flexible array design.
• 48V battery compatible (LiFePO4, other lithium, lead-acid) with selectable closed-loop BMS communication.
• Charges from solar, utility, or generator, expands to six units in parallel, and includes a Wi-Fi logger for app monitoring.

Free system-sizing help. Runtime, the batteries this inverter needs, and how many panels it supports all depend on your loads. Send us your appliance list and daily energy use and we'll help you spec the battery bank, solar array, and protection devices before you buy.

For permanent installation as part of a solar energy system. Design, wiring, grounding, and protection devices should be handled by a licensed electrician or qualified solar installer per the National Electrical Code and your local authority having jurisdiction (AHJ).

The Freedom 12K-B is a standalone (off-grid) solar storage inverter. Solar and battery energy do the everyday work, while the utility grid or a generator can step in to charge the batteries and pass power through to your loads when solar is low. It is not a grid-tie or grid-export inverter, and the manufacturer documentation does not describe selling power back to the utility. Utility input is used for charging and bypass only.

Why this inverter

• One integrated unit. Inverter, two solar charge controllers, and an AC charger share one enclosure, which simplifies component selection and system layout.
• Real 240V capability. Split-phase output can feed a 120/240V critical-load or off-grid distribution panel, within the inverter's load and phase limits.
• Grows with you. Start with one unit and add up to six in parallel as your needs increase.
• Flexible priorities. Four output modes plus timed charge/discharge let you favor solar, protect batteries, or use time-of-use rates.
• Included Wi-Fi monitoring. A Wi-Fi/GPRS logger ships in the box for remote monitoring via the mobile app.

Who it fits

Homeowners building whole-property or critical-load backup, off-grid and cabin owners, farms, workshops, and installers who want a straightforward off-grid platform. It's the right choice when your goal is energy independence with solar and batteries, with the grid or a generator as a backup charging source. It is not the right choice if you specifically need grid export / net metering or a UL 1741-listed grid-tie inverter.

Power, Solar & Battery

12kW split-phase pure sine wave power

The FR12K-B delivers 12,000W of continuous pure sine wave power, with up to 24,000W peak to accommodate brief starting surges, subject to the manufacturer's operating limits. Continuous output is what the inverter supplies hour after hour; peak output is a short surge reserve that helps start motors, compressors, and pumps that briefly draw far more than their running wattage. Pure sine wave output is suitable for many household electronics and variable-speed appliances; always confirm requirements for specialized or life-safety equipment.

Why 120/240V split-phase matters in the U.S.: Most American homes use split-phase service, 120V for lights, outlets, and small appliances, and 240V for well pumps, water heaters, dryers, ranges, and central air. The FR12K-B produces true 120/240V split-phase output (240V line-to-line, 120V line-to-neutral), so one unit can feed a standard 120/240V panel. It can also be set to 120V single-phase output.

Motors and transfer time: SunGoldPower rates the inverter for a motor load capacity of up to 6HP. Whether it starts a specific motor depends on that motor's locked-rotor (surge) current, so check the nameplate and consider a soft starter for large compressors or pumps. In bypass configurations, the typical transfer time is about 10ms.

Dual MPPT solar charging

Two independent MPPT solar charge controllers accept up to 13,200W of PV total (6,600W per MPPT). Each channel handles up to 22A and operates over a 125-425VDC window, with a hard 500VDC maximum open-circuit voltage. Two trackers let you run two different arrays (for example a south roof and a west roof, or different tilts and panel counts) and optimize each on its own, so shading or orientation on one array doesn't drag down the other. MPPT tracking efficiency is up to 99.9%.

Sizing your strings (important): keep each series string's cold-weather open-circuit voltage (Voc) below 500VDC. Panel Voc rises as temperature drops, so apply the temperature correction for the coldest expected morning at your site, not the standard test rating. A string that's safe on a warm afternoon can exceed 500V on a cold clear morning and damage the inverter, which is not covered by warranty. For full use of a channel, keep the operating voltage within the 125-425VDC window.

Battery compatibility, BMS communication & charging

The FR12K-B runs on a 48V (nominal) battery bank across a 40-60VDC range, and supports LiFePO4 and other lithium chemistries, lead-acid (sealed, gel, flooded), and a user-defined profile, with preset LFP options for 14S, 15S, and 16S packs. A no-battery setting exists, but a battery is required for the inverter to work as an off-grid backup system.

Size the battery for current, not just capacity. This is the detail most product pages skip. Operating near full 12kW output requires roughly 250A or more from a nominal 48V-class bank, depending on actual battery voltage and inverter efficiency, about 255A at 51.2V and rising toward ~272A near 48V (both at ~92% efficiency). The manual specifies battery wiring and protection for a maximum battery current of 260A, using 3/0 AWG (000 AWG) cable and a 300A DC breaker. Your bank and its BMS must be able to deliver around 250A or more continuously to reach full output. A single 48V/100Ah battery with a 100A BMS cannot do this alone, its BMS shuts down under heavy load to protect itself, so full-power systems generally use several batteries in parallel or high-current server-rack modules. Size for both the energy (kWh) you need overnight and the current (amps) your loads demand at once.

Closed-loop BMS communication: the inverter has CAN and RS485 ports and ships with a BMS communication cable. Closed-loop communication lets the battery report state of charge, voltage, and temperature and coordinate charge/discharge limits, which is more precise than voltage-only control. The protocol menu includes SunGoldPower, Pylontech, PACE, Luxpower, Deye, Ritar, Sunwoda, Oliter, Daking, AllGrand, and SNPOWER. Listing a protocol is not a compatibility guarantee. Closed-loop operation must be confirmed for your exact battery model, inverter firmware, protocol selection, and communication-cable pinout. Batteries without a confirmed match still run in open-loop (voltage-based) mode using the lithium or user-defined settings.

Recommended pairing: PowerMax 48V LiFePO4. We stock PowerMax 48V LiFePO4 batteries and pair them with the FR12K-B as a matched system, sized to deliver the ~250A or more this inverter needs at full output. They support closed-loop BMS communication with the FR12K-B using the matching protocol setting. Ask us to spec the right PowerMax bank for your loads.

Charging power:

• Max. solar (PV) charge current: 200A
• Max. utility or generator charge current: 120A
• Max. combined (hybrid) charge current: 200A
• Two charge modes: solar-only, or solar plus utility/generator

Note: LiFePO4 batteries should not be charged below freezing unless they have built-in heating. In cold climates, choose self-heating batteries or a heated enclosure.

Generator, Utility Charging, Monitoring & Parallel Expansion

Charge from utility or generator, without becoming grid-tied

The FR12K-B accepts utility or generator AC input (90-140VAC, 50/60Hz) to top up batteries and pass power through to loads during cloudy stretches or high demand. This does not make it a grid-export inverter; power flows in to charge, not out to the grid.

Match the input phase to your output mode. The AC input's phase configuration must match the selected output mode. A split-phase (120/240V) installation requires a compatible split-phase AC source, a single 120V generator will not correctly feed a 120/240V split-phase system. Plan your generator or utility connection around the output mode you intend to run.

Flexible generator port

The dedicated generator port can be set as a generator input (default) or as a secondary load output for non-critical ("smart") loads that the inverter can shed automatically during overload or low battery, then restore. That makes it easier to protect critical circuits while still powering optional ones when energy is available.

Automatic generator start

The inverter supports remote generator start/stop through its dry-contact port. This requires a generator with an automatic transfer switch (ATS) that supports remote start/stop. Confirm your generator's capability and wiring before relying on auto-start.

Wi-Fi monitoring and communication

A Wi-Fi/GPRS logger is included for monitoring status, production, and battery data from the mobile app. Built-in ports include RS485, CAN, USB, and dry contact. (The parameter table lists the Wi-Fi/GPRS module as external; the current packing list includes one, reflected in "What's Included.")

Parallel expansion and three-phase

Connect up to six matching units in parallel for a combined output of up to 72,000W, useful when loads grow, when you want extra surge headroom, or for redundancy. Units can be configured for single-phase, split-phase, or three-phase operation. A parallel communication cable is included with each unit.

Time-of-use and energy-saving

Timed charge and discharge (three programmable periods each) let you charge when rates are low and run on battery when rates are high. An energy-saving mode reduces idle draw by shutting off output under very light loads and restarting automatically when demand returns.

What Can This Inverter Power?

With 12kW continuous and up to 24kW peak split-phase output, the FR12K-B can run demanding 120V and 240V loads, often several at once. What it powers at any moment depends on the total of everything running together, each item's startup surge, and your battery bank's ability to supply the current. The ranges below are general planning estimates, not guarantees. Check each appliance's label (usually on the back, bottom, or inside a panel) for its real running watts and its startup surge, listed as locked-rotor amps (LRA), and add up everything that will run at the same time.

These are planning examples only. Your safe simultaneous load must stay within 12kW continuous (brief peak higher) and within your battery bank's continuous discharge rating.

How long will it run? (kW vs kWh)

Runtime is set by your battery energy in kWh, not the inverter's 12kW rating. kW is how fast energy is used; kWh is how much is stored. As a rough guide, divide your usable battery energy by your average load, then expect somewhat less in practice after usable depth-of-discharge limits, inverter losses (up to roughly 8%), temperature, and idle consumption. For example, a 30kWh nominal bank at a 4kW average load provides meaningfully less than 7.5 hours once those factors are applied; lighter loads last much longer, and daytime solar recharging extends it further.

Technical Specifications

All values are from the SunGoldPower Freedom 12K-B (FR12K-B) user manual parameter table.

AC output

Battery

Solar / MPPT input

Utility / generator input

Communication and monitoring

Physical and environmental

Certifications (per manual)

The manual does not list UL, ETL, CSA, IEEE 1547, or UL 1741 certification for this model. If your permit or utility interconnection requires a specific North American safety listing, verify current certification with SunGoldPower before purchasing.

What's Included, Requirements & Installation

In the box (per the manual packing list)

• 1 x Freedom 12K-B (FR12K-B) inverter
• 1 x Wi-Fi / GPRS logger
• 1 x parallel communication cable
• 1 x BMS communication cable
• 4 x SC50-8 copper lugs and 2 x SC95-8 copper lugs (cable terminals)
• Mounting hardware: expansion screws and machine screws
• 2 x screwdrivers (M8 socket driver and flat-head)
• User manual, warranty card, shipment inspection report, certificate of conformity

Sold separately / required for a complete system

The FR12K-B is the control center of a system, not a complete kit. You will also need:

• 48V battery bank sized for both energy (kWh) and current (~250A+) we stock compatible PowerMax 48V LiFePO4 batteries
• Battery cables (3/0 AWG / 000 AWG per manual) and a 300A DC breaker/disconnect (lugs are included; cable is not)
• Solar panels, PV wiring, connectors, and PV disconnects/breakers
• AC input/output wiring, breakers, and a loads subpanel
• Grounding hardware per NEC and local code
• If required by code: module-level rapid-shutdown (RSD) units and an accessible RSD switch
• Optional: generator with ATS for auto-start; soft starters for large motors

We can build the full parts list (batteries, cables, breakers, panels) to match this inverter. Reach out with your loads and site details.

Indoor installation only (IP20)

Rated IP20, indoor use only. Mount on a solid wall in a dry, ventilated space out of direct sunlight, with clearance for airflow. It is not weatherproof. Keep it within its 14°F to 131°F range; output derates above roughly 113°F.

Neutral-ground bonding

Off-grid systems need a single, correct neutral-ground bond for safety devices to work. The FR12K-B includes an automatic N-PE connection function that can be enabled so the bond is correct whether the system is on battery or on utility/generator bypass. Your installer should confirm the bonding scheme for your specific panel and transfer arrangement.

Rapid shutdown (RSD) and AFCI

The inverter includes an onboard PV rapid-shutdown initiator. SunGoldPower states the rapid-shutdown function is designed to meet NEC 690.12 (2017 and 2020) requirements when paired with compatible module-level rapid-shutdown devices and an accessible outdoor RSD switch (the manual references APsmart RSD equipment); those units and the switch are not included. An arc-fault (AFCI) function can also be enabled in the settings. Confirm the complete rapid-shutdown solution and requirements with your AHJ and installer.

Professional installation

This inverter has around 80 configurable settings and connects high-current DC and split-phase AC wiring. For safe, code-compliant, warranty-protected operation, installation and commissioning should be performed by a licensed electrician or qualified solar installer per the manufacturer manual, the NEC, and your AHJ.

Frequently Asked Questions