Marine Air Conditioning Shore Power Requirements
A unit that runs happily by itself may trip the pedestal when the charger, hot-water service or kettle joins it. List simultaneous loads before deciding the boat has enough supply.
01
10A and 15A Marina Shore Power Capacity
At a nominal 240 V, a 10 A connection represents about 2.4 kW and a 15 A connection about 3.6 kW before allowing sensible headroom. The label is not a target. Plugs, leads and connections warm under sustained load, and actual voltage can be lower at a busy marina.
These bars illustrate arithmetic, not a safe continuous rating or circuit design. Use the exact nameplate figures and installation manual, then have the vessel’s fixed wiring assessed by a licensed electrician familiar with marine installations.
02
Marine Air Conditioner Running Current and Starting Demand
A fixed-speed compressor briefly asks for substantially more current when it starts. A weak connection, long undersized lead, overloaded inverter or simultaneous charger surge can turn that brief event into a nuisance trip. Soft-start hardware may reduce the peak on compatible equipment, but it does not create more continuous capacity and must be approved for the unit.
| Load | Typical planning question | What to verify |
|---|---|---|
| Air conditioner + pump | Can it start at the lowest expected supply voltage? | Nameplate, manual and measured start/run behaviour |
| Battery charger | Does it return to full output after a night at anchor? | Input current at maximum charge rate |
| Hot water | Can it be interlocked or switched off while cooling? | Element wattage and circuit arrangement |
| Galley appliances | Will people use them without thinking about the AC? | Highest likely simultaneous combination |
03
Boat Air Conditioning Battery Energy and Inverter Limits
A battery bank is measured by usable energy, while the inverter also has a continuous and surge power limit. The overnight calculation must include compressor duty cycle, pump, blower and inverter losses. Cooling one closed sleeping cabin can be practical; cooling an open saloon all night may consume several times as much energy.
- Reduce the load first. Shade windows, cool the cabin before unplugging and close unused spaces.
- Use usable kilowatt-hours. Battery label capacity is not always available capacity, especially for lead-acid banks.
- Check the inverter twice. Continuous rating and surge behaviour are separate constraints.
- Plan replenishment. Solar production varies; generator use brings ventilation, exhaust and marina rules into the decision.
Run the interactive calculation in the main guide, then compare 12 V/24 V DC and 240 V systems. The result is an estimate, not an electrical design.