Sol-Ark 18K Hybrid All-in-One Inverter – 18K-2P-N
SKU18K-2P-N
The Sol-Ark 18K (18K-2P-N) is an outdoor-rated 48 V hybrid all-in-one inverter for large homes. One unit combines solar charging (three MPPTs), a battery inverter/charger, a 200 A grid passthrough and backup transfer. Sol-Ark rates it at 18,000 W continuous AC output...
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Product Overview
The Sol-Ark 18K (18K-2P-N) is an outdoor-rated 48 V hybrid all-in-one inverter for large homes. One unit combines solar charging (three MPPTs), a battery inverter/charger, a 200 A grid passthrough and backup transfer. Sol-Ark rates it at 18,000 W continuous AC output with 36,000 W of surge for 10 seconds.
Sol-Ark describes these as 48 V low-voltage hybrid inverters: the battery bank is a 48 V-class system, not a high-voltage battery. Sol-Ark describes them for grid-tied, backup and off-grid use, with automatic generator start.
Sol-Ark lists 120/240 V split-phase and 120/208 V grid voltages for this model, with a maximum output current of 75 A.
Best For
- Large homes on 120/240 V split-phase service that want whole-home backup: 18,000 W continuous and a 200 A grid passthrough.
- Heavy starting loads: Sol-Ark rates surge at 36,000 W for 10 seconds, which helps with well pumps and HVAC compressors.
- Large arrays and large 48 V battery banks: 28,800 W of usable PV power across three MPPTs and 350 A of battery charge/discharge current.
Key Features & Specifications
| Specification | Details |
|---|---|
| Product type | 48 V low-voltage hybrid all-in-one inverter (grid-tied, backup and off-grid operation); outdoor-rated |
| Model | 18K-2P-N (AltE part number); Sol-Ark datasheet PS-00036 Rev 8 covers model 18K-2P-LV (UL listed as Limitless 18K-2P-LV) |
| AC output | 18,000 W continuous at 240 V (15,600 W at 208 V); 36,000 W surge for 10 s; 75 A maximum output current |
| Grid voltage; grid passthrough | 120/240 V or 120/208 V; 200 A grid passthrough |
| PV input | 3 MPPTs, 2 strings each; maximum usable PV power 28,800 W; maximum STC-rated PV power 32,400 W |
| MPPT range; start-up voltage; maximum DC input | 150–425 V; 125 V; 500 V |
| Current per MPPT | 36 A operating; 54 A short-circuit |
| Battery | 48 V nominal (43–59 V operating range); 2 battery inputs (using only one derates output, per Sol-Ark); 350 A charge / 350 A discharge; lead-acid or lithium; CANbus, RS485 and Modbus RTU communication |
| GEN port | Bidirectional AC port for a generator, AC-coupled PV or an AC load; 28,800 W at 240 V (24,960 W at 208 V); 120 A |
| Efficiency | CEC 97.0%; maximum 97.6% |
| Parallel | Up to 12 units |
| Built-in protection | PV DC disconnect, PV arc fault detection, ground fault detection, PV rapid shutdown control, 200 A load breaker; DC Type II / AC Type III surge protection |
| Enclosure; temperature | IP65 / NEMA 3R; −40°C to 60°C, derating above 45°C |
| Dimensions; weight | 863 × 494 × 306 mm (34 × 19.4 × 12 in); 62.14 kg (137 lb) |
| Certifications (per Sol-Ark) | UL 1741 3rd Ed. SB, UL 1741 CRD-PCS, IEEE 1547-2018, UL 1699B PV DC AFCI, UL 1998, CSA C22.2 No. 107 |
| Warranty (per Sol-Ark) | 10 years standard |
| Source | Sol-Ark Limitless 18K-2P-LV datasheet PS-00036 Rev 8 (Sept. 9, 2026); Sol-Ark Premium 18K-2P product page; Sol-Ark's Low Voltage Battery Integration Guide (TB-00012 Rev. 7, effective March 24, 2026) |
What You May Also Need
Usually required
- A 48 V battery bank with closed-loop communication: The battery must fit the inverter's 48 V battery range. Sol-Ark's Low Voltage Battery Integration Guide (TB-00012 Rev. 7, effective March 24, 2026) lists the batteries Sol-Ark has certified, and covers the 18K, 15K and 12K outdoor inverters. One battery on that list is the Briggs & Stratton SimpliPHI 6.6, which connects through a 6.6/Sol-Ark crossover cable to the inverter's CAN port. Sol-Ark says its warranty does not cover damage caused by a battery that is not listed in the guide.
- Battery cables and DC overcurrent protection: Size the cables and fusing for the battery current in the table above, following Sol-Ark's and the battery maker's manuals.
- Solar panels wired in strings: String voltage must stay within the MPPT range and below the maximum DC input voltage at your site's coldest temperature.
May be required
- Disconnects and breakers: Your installation may need additional AC disconnects or breakers depending on whether you back up the whole home or selected loads.
- Module-level rapid shutdown devices: Rooftop arrays generally must meet NEC 690.12. The inverter provides rapid shutdown control; choose module-level devices that Sol-Ark lists as compatible in its current documents.
- A backup loads panel: Needed when you back up selected circuits rather than the whole home.
Optional upgrades
- Generator: Connects to the inverter's generator (GEN) input; Sol-Ark lists automatic generator start for this model.
- Additional 18K units: Sol-Ark lists up to 12 units in parallel.
Check current manufacturer documentation before combining components, especially batteries, inverters, communications equipment and system-control hardware.
Important Considerations
- Battery voltage window and AC-coupling limit. Sol-Ark's current datasheet lists a 43–59 V battery operating range and up to 28,800 W of AC-coupled PV through the GEN port at 240 V (24,960 W at 208 V). Choose a battery whose operating voltage stays inside that window.
- Model number. Sol-Ark's current datasheet names this inverter 18K-2P-LV, and the 18K-2P-N datasheet entry in Sol-Ark's document library now serves that sheet. Confirm the model on the unit label matches the documents you use for permitting.
- Use both battery inputs. Sol-Ark's datasheet notes that using only a single battery input derates the inverter and charger output.
- Check string voltage in cold weather. Keep each string's cold-weather Voc below 500 V and its current within 36 A per MPPT.
- Weight and mounting. At 137 lb, the inverter needs a wall and mounting method that can carry it; plan for at least two people to lift it.
- Battery firmware and settings. For reliable CANbus communication, Sol-Ark's battery integration guide (TB-00012 Rev. 7) says to update the inverter to firmware version C 1.4.5.2 or greater, and to program the inverter with the battery's charge and discharge settings.
- Professional installation. These inverters connect to the utility grid, batteries and the home's main panel. They should be installed by qualified installers under local electrical codes, with utility interconnection approval for grid-tied operation.