Wiring Starlink to 12V or 24V DC on a boat — and skipping the inverter for good.
The supplied AC power supply is convenient for a house, useless on a boat. Here is how to wire Starlink directly to a marine DC system — fuse sizing, wire gauge, voltage regulator selection, and the inverter losses you eliminate by doing it right.
The Starlink kit ships with an AC power supply because most customers plug it into a wall outlet. Boats don't have wall outlets — they have a 12V or 24V house bank, an inverter that turns DC into AC at a measurable cost, and a long-running engineering tradition of avoiding unnecessary conversion stages. The right way to power Starlink on a boat is to skip the inverter entirely and feed the antenna native DC.
This article is the practical guide. It covers what voltage the antenna actually wants, the converter selection that makes it work, the wire gauge and fuse sizing per ABYC standards, and the cabin-heat and house-bank wins that come from doing it correctly. None of this is exotic — it is just the standard treatment for any 48V load on a marine DC system.
"The antenna wants 48V DC. The wall wart wants AC. The boat wants neither — give it a DC-to-DC converter and step out of the way."
48V to 56V DC — and an honest amperage budget.
Both the Flat High Performance and Maritime antennas operate on 48V to 56V DC at the antenna feed. The supplied AC power supply takes 110V AC and outputs 56V DC over a single Ethernet-PoE-style cable. That last conversion stage — AC back to DC — is the one we eliminate.
- Flat High Performance.Average draw 50 to 75 watts, peak 110 watts during heater operation. At 48V, that is roughly 1 to 2.3 amps on the antenna feed.
- Maritime / High Performance.Average draw 90 to 110 watts, peak 150 watts. At 48V, roughly 1.9 to 3.1 amps on the antenna feed.
- Indoor router (Gen 3).Separate 12V DC feed at roughly 0.5 to 1 amp. Some installs run the router off a step-down from the 24V or 48V rail; either is fine.
For the full power-consumption picture and house-bank sizing, see our power draw and battery sizing article. This article focuses on the wiring path itself.
DC-to-DC step-up: the one component that does the work.
The whole conversion gets handled by a single component — a marine-grade DC-to-DC step-up converter. On 12V boats it goes 12V → 48V. On 24V boats it goes 24V → 48V. Quality matters; cheap eBay step-ups fail in marine environments and take the antenna with them.
- Capacity.Size for 200 watts continuous on a Flat High Performance, 300 watts continuous on a Maritime. Headroom prevents the converter running hot at peak heater load.
- Efficiency.Look for 90 percent or better. A good unit lives in this range; cheap units run 75 to 80 percent and dump the rest as heat.
- Marine certifications.IP67 or better, conformal-coated PCB, and ideally CE/FCC marked. Cheap units fail when condensation hits.
- Brands we install.Victron Orion-Tr, Mastervolt DC Master, Yacht Devices YDIB-04. All three are proven on Connecticut boats.
The converter typically mounts in an electrical locker, a flybridge console, or near the helm-station 48V bus on larger boats. Heat dissipation matters — give it 2 inches of clearance on every side.
ABYC E-11 numbers for the typical marine install.
Wire gauge is set by current and run length, not opinion. ABYC E-11 is the marine standard. The numbers below cover the typical install — confirm against your specific run on a longer or higher-current configuration.
- 12V supply, 10-foot run, 15A continuous worst case.10 AWG marine-grade tinned copper. Holds voltage drop under 3 percent. 15A or 20A ANL/MIDI fuse at the source, sized to the wire — not the load.
- 24V supply, 10-foot run, 7.5A continuous worst case.12 AWG tinned copper. 10A fuse at the source.
- 48V output to antenna, 50-foot run, 3A continuous worst case.The supplied Starlink cable is engineered for this run. Don't substitute. 5A or 7.5A inline fuse on the converter output.
- Indoor router 12V supply.14 AWG, 5A fuse. Keep the run short.
Ground returns are the same gauge as the positive feed. Negative bus to engine block via the boat's existing bonding system. Keep AC and DC routing physically separate per ABYC E-11.
"Wire gauge is set by current and run length. Opinions don't enter into it."
Three measurable wins, all of them real.
The reason we wire DC-direct on every install is not aesthetic. It is three real, measurable wins that show up the first weekend on the hook.
- 10 to 20 percent less power consumed.Inverter losses plus AC-to-DC supply losses stack to 15 to 20 percent on most installs. DC-to-DC at 90 percent is meaningfully cleaner. Over a season of at-anchor use, that is many amp-hours of house-bank capacity recovered.
- Less cabin heat.The wasted watts in inverter-and-supply double conversion show up as heat. Cabins are small and air conditioning is not free. Eliminating the inverter's contribution matters more than owners expect.
- One fewer failure point.The inverter is a complex device with switching electronics and a fan that pulls salt-laden air. Eliminating it from the Starlink path reduces what can fail. The house bank already needs an inverter for galley and AC loads — let it do that job, not also feed Starlink.
None of this is hypothetical. We measure draw on every install at handoff and the DC-direct numbers consistently come in 10 to 20 watts lower than the inverter path.
The four DIY mistakes we fix most often.
Owners who wire Starlink themselves usually run into the same four issues. Each one is preventable.
- Cheap step-up converter.An eBay 12V-to-48V at half the price is half the converter. Marine environments find them in a season. Use Victron, Mastervolt, or equivalent.
- Undersized wire on the supply side.14 AWG to a step-up running 110 watts at 12V is a fire-code problem. The math doesn't lie — current is power divided by voltage, and 12V means a lot of amps.
- No fuse, or fuse sized to the load.Fuses protect the wire. A 5A fuse on a 10 AWG run will trip nuisance; a 30A fuse on a 14 AWG run is dangerous. Match fuse to wire.
- Automotive PVC wire.Doesn't last in salt air. Tinned copper, marine-jacketed — non-negotiable on a boat.
For the broader DIY-vs-pro picture, see our DIY vs. professional install article. The wiring side is one of the four most common DIY failures we end up fixing.
DC-direct is the marine standard. The work is in doing it correctly.
Skipping the inverter is the right call on every Starlink boat install we deliver. The components are off-the-shelf, the math is settled, and the wins are real — less power consumed, less cabin heat, fewer failure points. The work is in choosing the right converter, sizing the wire and fuse correctly, and following ABYC E-11 the way every other 48V load on the boat already does.
Tell us about your boat and we'll specify the right DC path for the kit. Welcome aboard.