Nordhavn 40 electric repower: motor, battery and cable sizing

The Nordhavn 40 is a 12.1 m monohull with a 10.8 m waterline and 22,680 kg displacement. From those figures, the configurator's sizing model puts an electric conversion at 25 kW and 80 kWh on a 96 V system.

Boat data: Nordhavn — Nordhavn 40, checked 23 October 2026

Motor power

25 kW

22.6 kW needed at 6 kn

Battery pack

80 kWh

2 h at full rating, with reserve

DC design current

482 A @ 96 V

cabling burden: very heavy

Range on that pack

12 nm

at 6 kn

Open the Nordhavn 40 in the configurator Compare motors for 25 kW

The boat

Length: 12.12 m
Waterline length: 10.8 m
Beam: 4.42 m
Displacement: 22,680 kg
Hull: Full-displacement hull
Builder: Pacific Asian Enterprises (Nordhavn)
Original engine: John Deere 4045AFM85 — 160 hp, single shaft

Power needed by speed

Speed	Shaft power
3 kn	4.2 kW
4 kn	7.9 kW
5 kn	13.7 kW
6 kncruise target	22.6 kW
7 kn	36.2 kW
8 knhull speed	56.6 kW

The configurator's power-per-tonne heuristic, not a tank test — real boats vary by about ±25% with hull form, fouling, sea state and propeller. Near hull speed the power climbs steeply.

48 V or 96 V

48 V system

868 A

design DC current · cabling burden very heavy · 400 mm² for a short run

96 V systemconfigurator's choice

482 A

design DC current · cabling burden very heavy · 240 mm² for a short run

Motor lines that cover 25 kW at 96 V

ePropulsion

I-Series (I-10, I-20, I-40)

Inboard · 10–40 kW · 96 V class

From our motor comparison, matched by power and system voltage only — check drive type and fit with the maker.

What these numbers assume

The published displacement. Your boat loaded for cruising is heavier — use your own figure in the configurator.
Cruise target of 6 kn, which is 75% of the 8 kn hull speed.
A shaft drive, as the source states.
A pack sized for 2 hours at the motor's full rating, 15% reserve and 80% usable depth of discharge.
The configurator's power curve is fitted to this boat's published fuel burn (Nordhavn's around-the-world N40: 1.6 / 2.6 / 4.0 US gal/h at 6 / 7 / 8 kn), so the power-by-speed table matches that data by construction. Displacement is Nordhavn's published figure.

Nordhavn 40

Common questions

How many kW does a Nordhavn 40 need for electric propulsion?+

About 22.6 kW to hold 6 knots — 75% of its 8-knot hull speed — so the configurator suggests a 25 kW motor. Power rises steeply above that: about 56.6 kW at hull speed. These are estimates from the boat's published waterline length and displacement; real boats vary by roughly ±25%.

What size battery does a Nordhavn 40 need?+

The configurator sizes about 80 kWh of LiFePO4 for 2 hours at the motor's full 25 kW rating, with a 15% reserve and 80% usable depth of discharge — about 12 nautical miles at 6 knots. Cruising below full power stretches that.

Should a Nordhavn 40 use 48 V or 96 V?+

At 25 kW the design DC current is about 868 A at 48 V (cabling burden: very heavy) and about 482 A at 96 V (very heavy). The configurator picks 96 V for this boat: it stays on 48 V unless the 48 V current reaches its "very heavy" level.