Enter your 230 V appliances' power and system voltage to estimate inverter output and DC current. A fuse cannot be selected from that current alone: coordinate it with the conductor and the exact inverter manual.
Inverter, battery, wiring and fuse form the same system: sizing them separately usually leads to errors.
How to interpret the result
The inverter's continuous output must exceed the expected simultaneous load; its surge capacity must cover appliance startup. Size the fuse to protect the wiring and coordinate it with cable size, length, breaking capacity and manufacturer requirements. There is no universal fuse for a given wattage or battery Ah.
Indicative result. For high-current installations, use the manufacturer's diagrams and size cable, terminals and protection together.
This is a sizing aid. Always check the result against the equipment datasheet, conductor current-carrying capacity, temperature, connections and actual circuit protection.
Choose an inverter by separating continuous power, appliance startup and battery current demand.
Formula used by this tool
The tool adds 25% to continuous load and rounds up to hundreds of watts. Estimated DC current = simultaneous W ÷ (battery V × efficiency). The proposed surge rating is guidance, not a guarantee that an appliance will start.
Reproducible example
At 1,000 W simultaneous load, 12 V and 90% efficiency, estimated current is 92.6 A. The indicative continuous power is rounded to 1,300 W. Neither current nor power gives a universal fuse rating.
Build a realistic scenario
List appliances running at the same time, their documented surge and how long it lasts. W and VA are not interchangeable for every load. Also check published continuous output at the expected operating temperature.
Plan the complete circuit
Check BMS continuous and peak current, positive and negative cables, total length, terminals, fuse and breaking capacity. The exact model manual may specify minimum battery capacity and cable size. The 230 V side needs its own design and protection.
Is a higher-wattage inverter always better?
Not necessarily. A larger inverter may need more space and current and use more power at idle. For an occasional load, compare its actual need with the cost and limits of the complete system before upgrading.
