Engineering report · reviewed against NEC 2026 & BS 7671:2018+A2
Engineering Breakdown: Running a Kia EV9 (32A Level 2 EV Charger) on the EcoFlow Delta Pro 3
When pairing the EcoFlow Delta Pro 3 (4,096 Wh LiFePO4 capacity, 4,000 W continuous, 8,000 W surge) with a Kia EV9 (32A Level 2 EV Charger) (7,680 W running, 7,680 W starting surge), the system operates at 192% of continuous inverter capacity on a 240 V North American circuit and 184% on a 230 V UK/EU/AU circuit. Our North American verdict is Continuous Overload, so the runtime figures below are theoretical battery-energy values only. Wiring the connection over a 25 ft run calls for a 40 A breaker and 8 AWG copper, terminated at a NEMA 14-50P connection.
1. Compatibility Verdict & Inverter Load Utilization
In North American mode the Kia EV9 (32A Level 2 EV Charger) loads the EcoFlow Delta Pro 3's inverter to 192% of its 4,000 W continuous rating and 96% of its 8,000 W surge rating. Because continuous demand exceeds the inverter by 3,680 W, the unit will shut down within seconds of starting the load. The Tesla Powerwall 3 is the smallest compatible upgrade.
| Check | Load requires | EcoFlow Delta Pro 3 provides | US/NA | UK/EU/AU |
|---|---|---|---|---|
| Continuous output | 7,680 W (7,360 W @ 230V) | 4,000 W | Fail | Fail |
| Start-up surge | 7,680 W | 8,000 W | Pass | Pass |
| Voltage | 240 V / 230 V | 120/240 V / 230 V | Pass | Pass |
| Connection | NEMA 14-50P | NEMA L14-30R / NEMA 6-20R / TT-30R | UK/EU/AU: Type 2 EVSE · IEC 60309 32A Commando | |
An EVSE is a constant-current device: the vehicle draws exactly the current advertised by the J1772/NACS pilot signal, so the 7,680 W figure is both the running load and the start-up load — there is no motor inrush. That makes the calculation unusually clean. If you want to stay under the 80% sustained-load guideline, set the charge current in the vehicle app to 13 A or less, which keeps the EcoFlow Delta Pro 3 at roughly 3,120 W. A full battery delivers about 3.1 kWh into the pack after inverter and on-board charger losses, worth roughly 11 miles (18 km) of driving at 3.5 mi/kWh.
As a portable power station, the EcoFlow Delta Pro 3 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 L14-30R / NEMA 6-20R / TT-30R outlet.
Compatible alternative: the Tesla Powerwall 3 with the Kia EV9 (32A Level 2 EV Charger) report shows the full sizing for a unit that passes all three checks.
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 4,096 Wh rating to about 3,482 Wh of deliverable AC energy (85% system efficiency). EV charging runs at a fixed current, so the 100% row is the realistic figure; lower rows apply only if you schedule charging in intervals.
| Duty cycle | Average draw | Runtime (no solar) | Energy per 24 h |
|---|---|---|---|
| 25% | 1,920 W | 1.8 hrs | 46.1 kWh |
| 50% | 3,840 W | 54 min | 92.2 kWh |
| 65% | 4,992 W | 42 min | 119.8 kWh |
| 100% | 7,680 W | 27 min | 184.3 kWh |
Even at a 50% duty cycle the battery lasts 54 min, so plan on solar, grid or generator recharging for anything longer than an evening outage. Because the inverter cannot actually run this load in North American mode, treat these numbers as an energy-budget reference for a compatible inverter of the same capacity.
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: 7,680 W ÷ 240 V = 32.0 A, × 1.25 = 40.0 A, which rounds up to the next standard NEC 240.6 size of 40 A. The conductor must be protected by that breaker (75 °C ampacity at least 40 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) | 40 A | 8 AWG | 0.51% | Sized by ampacity |
| 50 ft (15.2 m) | 40 A | 8 AWG | 1.02% | Sized by ampacity |
| 75 ft (22.9 m) | 40 A | 8 AWG | 1.53% | Sized by ampacity |
| 100 ft (30.5 m) | 40 A | 8 AWG | 2.04% | Sized by ampacity |
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 32.0 A (the EVSE's 32 A pilot current at 230 V), so a 32 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) | 32 A | 4.0 mm² | 0.96% |
| 15 m (49 ft) | 32 A | 4.0 mm² | 1.92% |
| 22.5 m (74 ft) | 32 A | 4.0 mm² | 2.89% |
| 30 m (98 ft) | 32 A | 6.0 mm² | 2.57% |
Because the current is modest, 8 AWG copper stays within the voltage-drop target all the way to 100 ft.
4. Solar Array Recharge Time Breakdown
The EcoFlow Delta Pro 3 accepts up to 2,600 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 | 12.8 hrs | 2.8 | −3,520 W |
| 800 W | 640 W | 6.4 hrs | 1.4 | −3,200 W |
| 1,600 W | 1,280 W | 3.2 hrs | 0.7 | −2,560 W |
| 2,600 W | 2,080 W | 2.0 hrs | 0.4 | −1,760 W |
A typical 800 W portable array refills the battery in about 6.4 hrs of strong sun, while maxing out the 2,600 W input cuts that to 2.0 hrs. To fully offset the Kia EV9 (32A Level 2 EV Charger) at a 50% duty cycle (3,840 W average) during daylight you need roughly 4,800 W of panels, which exceeds this unit's 2,600 W input limit — solar can slow the drain but not eliminate it.
5. Frequently Asked Questions
Can the EcoFlow Delta Pro 3 run a Kia EV9 (32A Level 2 EV Charger)?
Not reliably in North America — our verdict is "Continuous Overload". The 7,680 W running load exceeds the 4,000 W inverter. The Tesla Powerwall 3 is a compatible alternative. In UK/EU/AU 230 V mode the verdict is "Continuous Overload".
How many miles of range can the EcoFlow Delta Pro 3 add to a Kia EV9?
A full 4,096 Wh charge delivers about 3.1 kWh to the vehicle battery after inverter (85%) and on-board charger (90%) losses — roughly 11 miles at 3.5 mi/kWh. Charging at this profile is not possible on this unit without reducing current or changing voltage.
What breaker and wire size do I need to connect a Kia EV9 (32A Level 2 EV Charger) to the EcoFlow Delta Pro 3?
In the US, 7,680 W at 240 V is 32.0 A; applying the NEC 125% continuous-load rule gives 40.0 A, so use a 40 A breaker and 8 AWG copper for runs up to 25 ft (0.5% voltage drop). In 230 V markets the load draws 32.0 A, protected by a 32 A MCB on 4.0 mm² cable for runs up to 7.5 m. Receptacle: NEMA 14-50P (US) or Type 2 EVSE · IEC 60309 32A Commando (UK/EU/AU).
How long does it take to recharge the EcoFlow Delta Pro 3 with solar panels?
With an 800 W array and an 80% real-world harvest factor, a full recharge takes about 6.4 hrs of peak sun (1.4 days at 4.5 peak-sun-hours). At its maximum 2,600 W solar input it drops to 2.0 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.