Air conditioning is one of the first areas where I would look at the power. Cooling capacity and electrical power are not the same thing, and a system that works fine on shore power can be a very heavy load on the battery.
Start with the rating plate – not just BTU or cooling kW
Find the electrical input power or current for the specific model. If it is 230 V, you also need to know whether it will run via shore power, generator, or inverter. If it is a DC model, the voltage and current must match the boat's 12/24/48 V system.
For inverter operation, the entire chain must be compatible
A 230 V air conditioner via an inverter requires more than just an inverter with sufficient continuous power. The compressor's start-up sequence, the inverter's specifications, the battery/BMS current limit, the cable, and the fuse must all be compatible.
Calculate in Wh
If a system uses 800 W of electricity and runs for one hour, the energy consumption is 800 Wh. If it runs for several hours from the battery, the battery requirement quickly becomes large. Therefore, I would calculate operating time and charging options before purchasing.
My checklist
- Supply voltage and electrical power.
- Starting current/start-up sequence of the compressor.
- The inverter's continuous and peak capacity.
- The battery and BMS's maximum current.
- Where the energy will come from again: shore power, generator, or solar.
See air conditioning · Calculate power consumption · See inverters