Running 240 V aboard
Marine Inverters
The inverter is what turns an adequate bank into an undersized one. A kettle drawing 85 A for twenty minutes is 28 Ah, and owners consistently underestimate it because the appliance is familiar and the current is not. Size the bank around the inverter's realistic duty, and fit the cable and fusing the inverter actually needs.
How to size an inverter
- Continuous rating matters more than surge: the surge figure sells the unit, the continuous figure runs it.
- A pure sine wave is not optional on a boat with electronics aboard.
- Cable and fusing are sized from the inverter's maximum DC current, which is larger than most owners expect.
- A combined inverter-charger saves space and a set of cables if you also need shore charging.
The options
Compare equipment ratings and applications
| Product | Continuous output | Price band | Best suited to |
|---|---|---|---|
| Victron Phoenix 1200VA inverter | 1000 W | $450–$650 | Cruising yachts running occasional 240 V rather than living on it. |
| Enerdrive ePower 2000W inverter | 2000 W | $1,100–$1,550 | Cruising yachts that want a kettle and a microwave without a refit. |
| Renogy 2000 W | 2000 W | $550–$800 | Houseboats and budget refits where 240 V is a convenience rather than a system. |
| Victron MultiPlus 3000VA inverter charger | 2400 W | $1,900–$2,600 | Liveaboards and catamarans running 240 V as normal service. |
Head to head
Asked most
What size inverter for a boat?
Add the continuous draw of everything you would run at once, not the peak of the largest appliance. A kettle and a microwave together is a 2000 W conversation; a laptop and a coffee grinder is a 600 W one.
Why is my bank flat after making coffee?
Because a 1200 W appliance draws about 100 A at 12 V. Twenty minutes of that is 33 Ah, which on a 200 Ah bank is a fifth of everything you own. The calculator will show you.