Engineering report · reviewed against NEC 2026 & BS 7671:2018+A2
Engineering Breakdown: Running a Tesla Model Y (Mobile Connector 32A) on the Selectronic SP Pro AU Off-Grid Inverter
When pairing the Selectronic SP Pro AU Off-Grid Inverter (10,240 Wh LiFePO4 capacity, 7,500 W continuous, 22,500 W surge) with a Tesla Model Y (Mobile Connector 32A) (7,680 W running, 7,680 W starting surge), the system operates at 98% of continuous inverter capacity on a 230 V UK/EU/AU circuit. At a 100% duty cycle and 85% inverter efficiency, a full battery delivers roughly 1.2 hrs of off-grid runtime. Wiring the connection over a 7.5 m run calls for a 32 A MCB and 4.0 mm² copper, terminated at a Type 2 EVSE · IEC 60309 32A Commando connection.
1. Compatibility Verdict & Inverter Load Utilization
In UK/EU/AU 230 V mode the Tesla Model Y (Mobile Connector 32A) loads the Selectronic SP Pro AU Off-Grid Inverter's inverter to 98% of its 7,500 W continuous rating and 33% of its 22,500 W surge rating. The pairing works, but running above 80% for hours raises internal temperatures and fan noise, and leaves little room for other loads. Treat it as a dedicated circuit.
| Check | Load requires | Selectronic SP Pro AU Off-Grid Inverter provides | UK/EU/AU |
|---|---|---|---|
| Continuous output | 7,360 W | 7,500 W | Pass |
| Start-up surge | 7,360 W | 22,500 W | Pass |
| Voltage | 230 V | 230 V | Pass |
| Connection | Type 2 EVSE · IEC 60309 32A Commando | Hardwired consumer unit (RCBO protected) |
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 25 A or less, which keeps the Selectronic SP Pro AU Off-Grid Inverter at roughly 6,000 W. A full battery delivers about 7.8 kWh into the pack after inverter and on-board charger losses, worth roughly 27 miles (44 km) of driving at 3.5 mi/kWh.
The Selectronic SP Pro AU Off-Grid Inverter is a heavy-duty off-grid inverter-charger built for rural properties, with a surge rating of 22,500 W — 3.0× its continuous output — designed to start bore pumps, workshop compressors and other large motors.
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 10,240 Wh rating to about 8,704 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% | 1,840 W | 4.7 hrs | 44.2 kWh |
| 50% | 3,680 W | 2.4 hrs | 88.3 kWh |
| 65% | 4,784 W | 1.8 hrs | 114.8 kWh |
| 100% | 7,360 W | 1.2 hrs | 176.6 kWh |
Even at a 50% duty cycle the battery lasts 2.4 hrs, so plan on solar, grid or generator recharging for anything longer than an evening outage.
3. BS 7671 / IEC 60364 Breaker & Cable Sizing
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% |
Moving the Selectronic SP Pro AU Off-Grid Inverter from 7.5 m to 30 m away forces the conductor up from 4.0 mm² to 6.0 mm² — park the unit as close to the load as ventilation and weather protection allow.
4. Solar Array Recharge Time Breakdown
The Selectronic SP Pro AU Off-Grid Inverter accepts up to 8,000 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% |
|---|---|---|---|---|
| 800 W | 640 W | 16.0 hrs | 3.6 | −3,040 W |
| 1,600 W | 1,280 W | 8.0 hrs | 1.8 | −2,400 W |
| 3,000 W | 2,400 W | 4.3 hrs | 0.9 | −1,280 W |
| 6,000 W | 4,800 W | 2.1 hrs | 0.5 | +1,120 W |
| 8,000 W | 6,400 W | 1.6 hrs | 0.4 | +2,720 W |
A typical 800 W portable array refills the battery in about 16.0 hrs of strong sun, while maxing out the 8,000 W input cuts that to 1.6 hrs. To fully offset the Tesla Model Y (Mobile Connector 32A) at a 50% duty cycle (3,680 W average) during daylight you need roughly 4,600 W of panels, which this unit can accept.
5. Frequently Asked Questions
Can the Selectronic SP Pro AU Off-Grid Inverter run a Tesla Model Y (Mobile Connector 32A)?
Yes. The Selectronic SP Pro AU Off-Grid Inverter delivers 7,500 W continuous and 22,500 W surge, covering the Tesla Model Y (Mobile Connector 32A)'s 7,360 W running and 7,360 W start-up draw at 98% inverter utilization, which is above the 80% guideline, so dedicate the unit to this load.
How many miles of range can the Selectronic SP Pro AU Off-Grid Inverter add to a Tesla Model Y?
A full 10,240 Wh charge delivers about 7.8 kWh to the vehicle battery after inverter (85%) and on-board charger (90%) losses — roughly 27 miles at 3.5 mi/kWh. At the full 7,360 W charge rate that takes 1.2 hrs.
What breaker and wire size do I need to connect a Tesla Model Y (Mobile Connector 32A) to the Selectronic SP Pro AU Off-Grid Inverter?
At 230 V the load draws 32.0 A. Under BS 7671 / IEC 60364 the protective device must be at least the design current (Ib ≤ In ≤ Iz), so use a 32 A MCB with RCD protection on 4.0 mm² copper cable for runs up to 7.5 m (1.0% voltage drop). Connection: Type 2 EVSE · IEC 60309 32A Commando.
How long does it take to recharge the Selectronic SP Pro AU Off-Grid Inverter with solar panels?
With an 800 W array and an 80% real-world harvest factor, a full recharge takes about 16.0 hrs of peak sun (3.6 days at 4.5 peak-sun-hours). At its maximum 8,000 W solar input it drops to 1.6 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.