Goals of the Electronics Refit#
Before sizing the specific components, the following goals have been defined for the refit project:
- Energy Autonomy: The boat should be as independent from shore power as possible and be powered by renewable energy sources such as solar energy.
- Safety and Redundancy: The electrical system must be reliable to minimize failures. Critical systems such as navigation and communication require backup solutions.
- Efficient Energy Management: Battery capacity and the charging system must be adequately sized to power all consumers without bottlenecks.
- Integration of Modern Navigation Electronics: Chartplotter, AIS, radio, and sensors should be networked and efficiently integrated into the onboard power system.
- Smart Monitoring: Monitoring of energy flows, battery voltage, and charge status should be available via a mobile app or a central display.
Power Supply and Battery Bank#
Consumption Analysis#
To properly size the power supply, the average consumption values of the main consumers were determined:
| Consumer | Power (W) | Operating Time (h/day) | Energy Consumption (Wh/day) |
|---|---|---|---|
| Compressor Fridge | 18 | 24 | 432 |
| Autopilot | 15 | 6 | 90 |
| NMEA Sensors/Instruments | 24 | 6 | 144 |
| Interior Lighting | 5 | 12 | 60 |
| Navigation Lighting | 8 | 8 | 64 |
| Total | 790 Wh/day |
Battery Capacity#
Since a battery should not be fully discharged, the required capacity is calculated with a safety factor. When using lithium batteries (LiFePO4), a discharge depth of around 80% can be assumed.
Required battery capacity: 790 Wh/day / 12 V = 65.83 Ah
With a safety factor of 1.5: 65.83 Ah * 1.5 = 98.75 Ah
Recommended battery capacity: 100 Ah LiFePO4
Charging Sources#
To recharge the battery, various charging sources are planned:
- Solar System:
- 2 × 100 W solar panels (Total: 200 W)
- MPPT charge controller for maximum efficiency
- Shore Power:
- 20 A charger with LiFePO4 profile
- Existing charger for the starter battery
Next Steps#
- Selection of specific components (manufacturers, models)
- Integration into the existing onboard power system
- Planning of wiring and fuses
- Land-based test setup to validate the sizing
Further details on the individual components will follow in the upcoming articles of the Electronics Refit series.