Choosing an inverter for a caravan or 4WD
Understand continuous power, startup surge and battery-side current before choosing a 12V-to-240V inverter.
Size the inverter for both continuous and startup loads, and confirm that the battery, cabling, fusing and installation can safely support it.
Identify what you need to run
List the watts of each 240V appliance that may run at the same time. Appliances with motors or compressors may need substantially more power when starting.
A large inverter does not create extra battery capacity; higher-power loads can drain a battery quickly.
Continuous power versus surge
Compare the inverter’s continuous rating and surge capability against your appliances’ requirements. Marketing peak ratings alone are not a sound basis for selection.
Pure sine wave output is commonly preferred for sensitive electronics and many appliances, but always check manufacturer requirements.
Understand the 12V side
A 1,000W output load can require roughly 90A or more from a nominal 12V battery after conversion losses. Exact current depends on voltage and efficiency.
High-current DC wiring, protection, ventilation and mounting require appropriate design. In Australia, 240V installation work may require a licensed electrician; do not attempt fixed wiring yourself.
Before you buy: checklist
- Simultaneous appliance watts
- Startup surge requirements
- Continuous and surge inverter ratings
- Battery maximum discharge current
- DC cable sizing and fuse protection
- Qualified electrical installation where required
Frequently asked questions
Can I use a 2000W inverter with a 100Ah battery?
It depends on the battery BMS discharge rating, wiring, expected load and installation. Battery Ah alone does not establish suitability.
Do I need a pure sine wave inverter?
Many electronics and appliances work best with pure sine wave output; follow the appliance manufacturer’s guidance.