Beneteau Oceanis 40 — 24V Bluewater Cruiser
sailboat · 24V system · Lagos, Portugal
Trans-Atlantic-ready 40-footer running a 24V house bank with 600Ah LiFePO4. Staged in Lagos, Portugal preparing for an Atlantic crossing. Heavy watermaker + Starlink + AIS + autopilot 24/7.
Daily load
6,811 Wh
Daily Ah
284 Ah
Battery
1600 Ah LiFePO4
Solar
2000 W
Load budget
| Load | Watts | Qty | Hrs/Day | Wh/Day |
|---|---|---|---|---|
| Starlink | 75 | 1 | 20 | 1,500 |
| Watermaker Feed Pump | 60 | 1 | 4 | 240 |
| Watermaker | 300 | 1 | 3 | 900 |
| Chartplotter | 25 | 1 | 10 | 250 |
| AIS TransponderCRITICAL | 5 | 1 | 24 | 120 |
| Autopilot | 40 | 1 | 12 | 480 |
| Radar | 40 | 1 | 3 | 120 |
| VHF Radio (Standby)CRITICAL | 5 | 1 | 24 | 120 |
| Navigation LightsCRITICAL | 15 | 1 | 12 | 180 |
| 12V Marine Fridge | 45 | 1 | 18 | 810 |
| Chest Freezer | 80 | 1 | 12 | 960 |
| Laptop | 60 | 2 | 4 | 480 |
| Induction Cooktop | 1800 | 1 | 0.25 | 450 |
| Interior LED Strip | 12 | 2 | 5 | 120 |
| Wind Instrument | 3 | 1 | 24 | 72 |
| Bilge PumpCRITICAL | 30 | 1 | 0.3 | 9 |
Battery bank
16 × 200Ah (2S8P) for 24V/1600Ah
Your daily consumption is 284Ah. With 4 days of autonomy, you need 1135Ah of usable capacity. LiFePO4 (Lithium Iron Phosphate) batteries should only be discharged to 80% depth of discharge, so you need 1419Ah of total capacity. We recommend a 1600Ah bank (16 × 200Ah (2S8P) for 24V/1600Ah), giving you 1280Ah of usable capacity — enough for 4 days without any charging.
Solar array
10 × 200W panels · 105A charge controller
Your daily consumption is 6811Wh. With 5 peak sun hours, a 75% system efficiency factor, and LiFePO4 (Lithium Iron Phosphate) round-trip efficiency of 96%, you need 1892W of solar panels. We recommend 10 × 200W panels (2000W total). This array will produce approximately 313Ah per day at 24V. You'll need a charge controller rated for at least 105A. MPPT recommended — higher efficiency at this array size.
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