12V vs 230V Watermaker Power Supply
Choose the right power source based on batteries, generator and shore power
Most buyers start with capacity (litres/hour), but the real limiting factor is usually what power is already available on your boat. A 12V unit can run at anchor from the battery bank without a generator; 230V models deliver higher output but require AC power. The wrong voltage choice either leaves the unit unused or drains your batteries in a few hours.
This guide clarifies which Seacraft SCW voltage group fits your setup. For capacity calculations see how to choose watermaker capacity for a yacht; for the full selection flow see our product selection guide.
3 Questions First
- Do you have reliable 230V AC onboard?
- How often does the generator run?
- At anchor, are you battery-only?
Seacraft SCW Series — Power Groups
Each model is designed for a specific voltage and frequency. Models are not interchangeable across voltage groups — selection must match your existing electrical infrastructure.
| Power Supply | Models | Hourly Output | Typical Vessel |
|---|---|---|---|
| 12V DC (24V option) | SCW-30, SCW-50 | 30–60 L/hour | Small sailboat, catamaran, low crew count |
| 230V / 50Hz AC | SCW-100 – SCW-350 | 100–350 L/hour | Motor yacht, gulet, large sailboat |
| 380V / 50Hz AC | SCW-500, SCW-1000 | 500–1000 L/hour | Commercial vessel, large fishing boat, shipyard |
12V DC Watermaker — When Is It the Right Choice?
12V models run directly from the battery bank. No generator or shore power is required, making them the most practical option for sailboats that stay at anchor on batteries alone. Solar or wind charging can support the system — see our 12V watermaker and solar panel guide.
Seacraft offers two 12V capacity options:
- SCW-30 — 30 L/hour, approx. 120 W draw, 8–10 A current. For small boats and 1–3 crew.
- SCW-50 — 50–60 L/hour, approx. 550 W draw, ~43 A current. For mid-size sailboats with higher daily demand.
The critical factor on 12V is battery capacity and charge balance. SCW-50 draws significantly more current than SCW-30; running the watermaker alongside fridge, autopilot or inverter loads can drain the bank quickly. Consider daily run time and how you recharge — not just the watt rating on the spec sheet.
12V Fit Profile
- 8–18 m sailboat or catamaran
- No regular generator, or rarely used
- Shore power at marina nights but anchoring by day
- Daily need around 200 L or less
Compare SCW-30 and SCW-50 in our SCW-30 vs SCW-50 comparison.
230V AC Watermaker — When Is It the Right Choice?
230V / 50Hz models are standard on motor yachts, gulets and large sailboats. When the generator is running or you are connected to marina shore power, you can produce at 100–350 L/hour depending on model — meeting demand that 12V units cannot cover in reasonable run times.
For example, SCW-150 draws approximately 2.2 kW and produces 150 L/hour. That load is not a sustainable scenario from a 12V bank through an inverter — generator or shore power is the practical solution.
The SCW-100 INV PRO is designed for compatibility with inverters of 2000 W and above. Inverter sizing, battery capacity and concurrent loads must still be assessed during a site survey — the same inverter answer does not apply to every boat.
230V Fit Profile
- 16 m+ motor yacht, gulet or large sailboat
- Onboard generator or regular marina shore power
- Daily need above 200 L
- High crew and guest count
Use our capacity guide for daily litres; this article covers power, that one covers output sizing.
Scenarios by Vessel Profile
These examples are starting points; final model selection requires both electrical setup and daily consumption to be assessed together.
Marina nights — mid-size sailboat
16 m catamaran, shore power available, ~220 L/day, anchoring by day.
Power: 12V (anchor) or 230V (marina)
Note: 230V possible on marina shore power at night; 12V limits apply when anchored all day. Both scenarios are planned during survey.
Gulet — blue cruise
24 m gulet, 12+ people, heavy shower use, ~500–600 L/day.
Power: 230V AC (generator)
Direction: SCW-150 or SCW-350. Gulet water needs guide
Running 230V from inverter
12V boat owner wants to run SCW-150 from inverter.
General view: Not practical
2 kW+ continuous load needs a large battery bank and high-amp inverter. Even SCW-100 INV PRO requires survey assessment. Motor yachts typically use generator-fed 230V.
5 Steps to Choose Power Supply
Document existing infrastructure
Battery bank capacity (Ah), generator yes/no, shore power outlet, inverter rating (W) — write down what you have.
Define usage scenario
Where will you run the unit: anchor only, marina nights, during generator hours?
Calculate daily need
Litres per day shows whether 12V is enough. 250 L+ usually points to 230V.
Match voltage group
12V → SCW-30/50 · 230V → SCW-100–350 · 380V → SCW-500/1000. Moving up a voltage group may require infrastructure work.
Confirm with survey
Cable runs, breaker lines, pump location and concurrent loads are only clear after on-site inspection. Request a survey rather than a phone-only model pick.
12V vs 230V — Quick Comparison
| Criteria | 12V DC | 230V AC |
|---|---|---|
| Power source | Battery bank (solar/wind optional) | Generator, marina shore power |
| Typical output | 30–60 L/hour | 100–350 L/hour |
| Independence at anchor | High — no generator required | Low — AC power needed |
| Current / power draw | 8–43 A range (by model) | ~2 kW and above (by model) |
| Via inverter | Not needed (direct DC) | Impractical for large models; SCW-100 INV needs survey |
| Typical vessel | 8–18 m sailboat, small crew | 16 m+ motor yacht, gulet |
Frequently Asked Questions
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