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GRIDSPEC
Verified Engineering Spec • NEC 2026 / UL 9540

EV, Solar & Battery Compatibility Sizer

Pick any of 35 power stations and 53 appliances or EVs to see verdict, runtime, solar recharge time and the exact breaker and cable size — under NEC or IEC rules.

Configure your system

800 W
25 ft (7.6 m)
100%
Source outlets
NEMA L14-30R / NEMA 6-20R / TT-30R
Load connection
NEMA 14-50P
EV range rate
≈ 24 mi (39 km) of range per hour of charging
Recommended Upgrade

Tesla Powerwall 3 (11,500 W, higher inverter output) runs this load at 67% utilization.

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Continuous Overload

7,680 W continuous draw exceeds the 4,000 W inverter rating.

Short by 3,680 W — the inverter will shut down under sustained load.

Continuous load
192%
Runtime (no sun)
—
Inverter cannot sustain load
Solar recharge
6.4 hrs
1.4 sun-days at 800 W
Min. copper wire
8 AWG
0.5% drop @ 25 ft
Overcurrent device
40A Breaker
32.0A load × 1.25 = 40.0A
Live schematic & breaker sizing diagram 120/240V Split-Phase • NEC 125% Rule
SOLAR PV INPUT 800 W PV MC4 / XT60 · MPPT POWER SOURCE / INVERTER EcoFlow Delta Pro 3 4,096 Wh • 4,000 W 8,000 W surge • 120/240V 192% load 40A OCPD 8 AWG Cu 32.0A @ 240V CONNECTED LOAD Tesla Model Y (Mobile Connector 32A) 7,680 W running 7,680 W surge 240V load
1

Continuous & surge check

Compressors and pump motors pull 2–4× their running power for a split second at start-up. We compare both running and locked-rotor watts against the inverter’s continuous and surge ratings, and flag anything above the 80% sustained-load guideline.

2

240V split-phase check

North American EV chargers, dryers, well pumps and central AC need 120/240 V split-phase power. A 120 V-only station fails these loads regardless of battery size — and we suggest the leanest 240 V-capable alternative automatically.

3

Breaker & cable sizing

Breakers follow the NEC 125% continuous-load rule (or IEC Ib ≤ In ≤ Iz), and copper conductors are upsized until voltage drop stays under 3% for your exact cable run — in AWG or mm².

The leanest fully compatible power source for each load — 1,258 of 1,855 pairings pass all checks.

Power station & home battery directory

35 portable power stations, whole-home batteries and hybrid inverters — each with a full compatibility hub.

Appliance & EV directory

53 high-draw loads with running watts, start-up surge and voltage profiles.

Why sizing a power station is harder than reading the box

Marketing pages lead with battery capacity, but capacity only decides how long something runs. Whether it runs at all depends on three other numbers: continuous inverter output, surge output and output voltage. A 5 kWh battery with a 120 V-only inverter cannot start a 240 V deep-well pump, while a smaller 240 V split-phase unit can. GridSpec evaluates all three for every combination in our database and publishes a dedicated report for each one.

Each report also translates the result into installation terms an electrician will recognise — breaker size, copper gauge, voltage drop and receptacle type — for both North American (NEC) and UK, European and Australian (IEC 60364 / BS 7671 / AS/NZS 3000) wiring rules. Solar recharge times use a realistic 80% harvest factor and 4.5 peak-sun-hours rather than ideal laboratory conditions.

Frequently asked questions

How does GridSpec decide whether a power station can run an appliance?

Every pairing must pass three independent checks: the inverter’s continuous rating must exceed the appliance’s running watts, its surge rating must exceed the start-up (locked-rotor) watts, and its output voltage must match — a 240 V well pump or EV charger cannot run from a 120 V-only unit no matter how large the battery.

Why do runtimes assume 85% efficiency?

Converting DC battery energy into AC household power loses energy as heat in the inverter, and battery management reserves part of the pack. Across independent bench tests of LiFePO4 power stations, 82–90% end-to-end efficiency is typical, so 85% is a realistic planning figure.

What is the difference between the US/NA and UK/EU/AU modes?

US/NA mode applies 120/240 V split-phase voltages, AWG copper sizes and the NEC 125% continuous-load rule. UK/EU/AU mode applies 230 V single-phase supply, metric mm² cable sizes, IEC 60898 MCB ratings and the IEC 60364 / BS 7671 rule that design current must not exceed the breaker rating.

Are GridSpec results a substitute for an electrician?

No. The calculations are engineering estimates for planning and purchasing. Any connection to a home’s wiring requires a listed transfer switch or interlock and should be installed by a licensed electrician under local permit.