Engineering report · reviewed against NEC 2026 & BS 7671:2018+A2
Engineering Breakdown: Running a 12,000 BTU Inverter Ductless Mini-Split (120V) on the EcoFlow Delta Pro (Gen 1)
When pairing the EcoFlow Delta Pro (Gen 1) (3,600 Wh LiFePO4 capacity, 3,600 W continuous, 7,200 W surge) with a 12,000 BTU Inverter Ductless Mini-Split (120V) (1,050 W running, 1,350 W starting surge), the system operates at 29% of continuous inverter capacity on a 120 V North American circuit and 29% on a 230 V UK/EU/AU circuit. At a 100% duty cycle and 85% inverter efficiency, a full battery delivers roughly 2.9 hrs of off-grid runtime. Wiring the connection over a 25 ft run calls for a 15 A breaker and 14 AWG copper, terminated at a Hardwired 120V / NEMA 5-15P connection.
1. Compatibility Verdict & Inverter Load Utilization
In North American mode the 12,000 BTU Inverter Ductless Mini-Split (120V) loads the EcoFlow Delta Pro (Gen 1)'s inverter to 29% of its 3,600 W continuous rating and 19% of its 7,200 W surge rating. Both figures are under the 80% sustained-load guideline, so this is a comfortable, verified match with 2,550 W of spare capacity for lights, a router or a refrigerator on the same unit.
| Check | Load requires | EcoFlow Delta Pro provides | US/NA | UK/EU/AU |
|---|---|---|---|---|
| Continuous output | 1,050 W | 3,600 W | Pass | Pass |
| Start-up surge | 1,350 W | 7,200 W | Pass | Pass |
| Voltage | 120 V / 230 V | 120 V / 230 V | Pass | Pass |
| Connection | Hardwired 120V / NEMA 5-15P | NEMA TT-30R / 5-20R | UK/EU/AU: Hardwired via DP isolator · IEC 60309 32A | |
Compressor-driven HVAC equipment is the hardest category for any inverter because of locked-rotor amperage (LRA): for a fraction of a second the motor pulls 1.3× its running power (1,350 W here). The EcoFlow Delta Pro (Gen 1) is rated for 7,200 W of surge, which covers that inrush. Thermostat cycling means the compressor rarely runs 100% of the time; mild weather typically produces 30–50% duty cycles, while peak summer afternoons push toward 80–100%. Fitting a soft-start module (Micro-Air EasyStart, SoftStartRV or a variable-speed inverter compressor) is the single cheapest way to make a marginal pairing reliable.
As a portable power station, the EcoFlow Delta Pro (Gen 1) integrates the LiFePO4 battery, inverter, MPPT solar controller and AC outlets in one chassis, so it can be wheeled to the load or connected to a transfer switch through its NEMA TT-30R / 5-20R outlet.
2. Real-World Runtime by Duty Cycle
Nameplate capacity is not usable capacity. DC-to-AC conversion, battery management overhead and cell protection reduce the 3,600 Wh rating to about 3,060 Wh of deliverable AC energy (85% system efficiency). Duty cycle is the share of each hour the load actually draws its running power — thermostats, pressure switches and intermittent use all lower it.
| Duty cycle | Average draw | Runtime (no solar) | Energy per 24 h |
|---|---|---|---|
| 25% | 263 W | 11.7 hrs | 6.3 kWh |
| 50% | 525 W | 5.8 hrs | 12.6 kWh |
| 65% | 683 W | 4.5 hrs | 16.4 kWh |
| 100% | 1,050 W | 2.9 hrs | 25.2 kWh |
Even at a 50% duty cycle the battery lasts 5.8 hrs, so plan on solar, grid or generator recharging for anything longer than an evening outage.
3. NEC 125% Breaker & Copper Wire Gauge Sizing
NEC 210.19(A) and 210.20(A) require conductors and overcurrent devices for continuous loads — anything running three hours or more, which includes EV charging and HVAC — to be rated at 125% of the load current. For this pairing: 1,050 W ÷ 120 V = 8.8 A, × 1.25 = 10.9 A, which rounds up to the next standard NEC 240.6 size of 15 A. The conductor must be protected by that breaker (75 °C ampacity at least 15 A) and keep round-trip voltage drop at or below 3%, so longer runs are upsized.
Voltage drop % = (2 × L × I × R) ÷ V × 100
North America (NEC, THHN copper, 75 °C)
| One-way distance | Breaker | Min. copper | Voltage drop | Note |
|---|---|---|---|---|
| 25 ft (7.6 m) | 15 A | 14 AWG | 1.12% | Sized by ampacity |
| 50 ft (15.2 m) | 15 A | 14 AWG | 2.24% | Sized by ampacity |
| 75 ft (22.9 m) | 15 A | 12 AWG | 2.11% | Upsized for voltage drop |
| 100 ft (30.5 m) | 15 A | 12 AWG | 2.81% | Upsized for voltage drop |
UK / EU / Australia (IEC 60364 / BS 7671, PVC copper, method C)
IEC-based codes size protection by design current rather than a blanket 125% multiplier: Ib ≤ In ≤ Iz. At 230 V the load draws 4.6 A, so a 6 A Type B/C MCB with RCD protection applies. In the UK, BS 7671 Section 722 additionally requires a dedicated circuit and Type A or Type B RCD for EV charge points.
| One-way distance | MCB | Min. cable | Voltage drop |
|---|---|---|---|
| 7.5 m (25 ft) | 6 A | 1.5 mm² | 0.36% |
| 15 m (49 ft) | 6 A | 1.5 mm² | 0.72% |
| 22.5 m (74 ft) | 6 A | 1.5 mm² | 1.08% |
| 30 m (98 ft) | 6 A | 1.5 mm² | 1.44% |
Moving the EcoFlow Delta Pro (Gen 1) from 25 ft to 100 ft away forces the conductor up from 14 AWG to 12 AWG — park the unit as close to the load as ventilation and weather protection allow.
4. Solar Array Recharge Time Breakdown
The EcoFlow Delta Pro (Gen 1) accepts up to 1,600 W of photovoltaic input. Real arrays rarely deliver nameplate output, so we apply an 80% harvest factor for MPPT conversion, cell temperature and soiling, and convert hours to days using 4.5 peak-sun-hours — a conservative annual average for the US, southern Europe and Australia (UK winters can fall below 1.5).
| PV array | Real harvest | 0–100% recharge | Sun-days @ 4.5 PSH | Net with load @ 50% |
|---|---|---|---|---|
| 400 W | 320 W | 11.3 hrs | 2.5 | −205 W |
| 800 W | 640 W | 5.6 hrs | 1.3 | +115 W |
| 1,600 W | 1,280 W | 2.8 hrs | 0.6 | +755 W |
A typical 800 W portable array refills the battery in about 5.6 hrs of strong sun, while maxing out the 1,600 W input cuts that to 2.8 hrs. To fully offset the 12,000 BTU Inverter Ductless Mini-Split (120V) at a 50% duty cycle (525 W average) during daylight you need roughly 700 W of panels, which this unit can accept.
5. Frequently Asked Questions
Can the EcoFlow Delta Pro (Gen 1) run a 12,000 BTU Inverter Ductless Mini-Split (120V)?
Yes. The EcoFlow Delta Pro (Gen 1) delivers 3,600 W continuous and 7,200 W surge, covering the 12,000 BTU Inverter Ductless Mini-Split (120V)'s 1,050 W running and 1,350 W start-up draw at 29% inverter utilization.
How long will the EcoFlow Delta Pro (Gen 1) run a 12,000 BTU Inverter Ductless Mini-Split (120V)?
With 3,600 Wh of capacity and 85% inverter efficiency, expect about 2.9 hrs of continuous operation and 5.8 hrs at a 50% duty cycle. Adding solar input during the day extends this further.
What breaker and wire size do I need to connect a 12,000 BTU Inverter Ductless Mini-Split (120V) to the EcoFlow Delta Pro (Gen 1)?
In the US, 1,050 W at 120 V is 8.8 A; applying the NEC 125% continuous-load rule gives 10.9 A, so use a 15 A breaker and 14 AWG copper for runs up to 25 ft (1.1% voltage drop). In 230 V markets the load draws 4.6 A, protected by a 6 A MCB on 1.5 mm² cable for runs up to 7.5 m. Receptacle: Hardwired 120V / NEMA 5-15P (US) or Hardwired via DP isolator · IEC 60309 32A (UK/EU/AU).
How long does it take to recharge the EcoFlow Delta Pro (Gen 1) with solar panels?
With an 800 W array and an 80% real-world harvest factor, a full recharge takes about 5.6 hrs of peak sun (1.3 days at 4.5 peak-sun-hours). At its maximum 1,600 W solar input it drops to 2.8 hrs.
Methodology & safety note
Specifications come from manufacturer datasheets in our open dataset; ampacity and resistance values follow NEC Table 310.16 and Chapter 9 Table 8, and BS 7671 Appendix 4. Calculations assume copper conductors, 30 °C ambient and no bundling derating. Inverter-to-panel connections require a listed transfer switch or interlock to prevent back-feeding the grid. These results are an engineering estimate, not a substitute for a licensed electrician and local permit. See our methodology and safety disclaimer.