PowerLabGallery · Community design

Westsail 32 — Full-Time Liveaboard on AGM

sailboat · 12V system · Sausalito, CA

Classic Westsail 32 kept on a mooring in Sausalito Bay. Three 100Ah AGMs feeding minimal liveaboard loads year-round. Deliberately simple — no watermaker, propane cooking, minimal electronics. 3 days autonomy sized for Bay Area fog stretches.

Daily load

2,266 Wh

Daily Ah

189 Ah

Battery

1200 Ah AGM

Solar

800 W

Load budget

LoadWattsQtyHrs/DayWh/Day
12V Marine Fridge45114630
Anchor LightCRITICAL10110100
LED Cabin Light53575
Laptop6013180
Phone Charger101330
WiFi Router10124240
Freshwater Pump6010.318
Bilge PumpCRITICAL3010.515
Reading Light32318
Dehumidifier20014800
VHF Radio (Standby)CRITICAL5124120
Hatch Fan101440

Battery bank

6 × 200Ah in parallel

Your daily consumption is 189Ah. With 3 days of autonomy, you need 566Ah of usable capacity. AGM (Absorbed Glass Mat) batteries should only be discharged to 50% depth of discharge, so you need 1133Ah of total capacity. We recommend a 1200Ah bank (6 × 200Ah in parallel), giving you 600Ah of usable capacity — enough for 3 days without any charging.

Solar array

4 × 200W panels · 84A charge controller

Your daily consumption is 2266Wh. With 4.8 peak sun hours, a 75% system efficiency factor, and AGM (Absorbed Glass Mat) round-trip efficiency of 83%, you need 758W of solar panels. We recommend 4 × 200W panels (800W total). This array will produce approximately 240Ah per day at 12V. You'll need a charge controller rated for at least 84A. MPPT recommended — higher efficiency at this array size.

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