Seakeeper Power Issues — Electrical System Audit Guide

Power Requirements by Model

Understanding real-world power draw is essential. Manufacturer specs list continuous draw; spin-up is 2–3x higher for 30–90 seconds.

SK2 / SK6

12V DC · 25–35A cont · 60–90A spin-up

SK9 / SK16

24V DC · 40–55A cont · 100–140A spin-up
or AC 230V · 15–25A cont

SK18+

AC 230V/400V · 30–55A cont
Soft-start required

The #1 Mistake: Sizing the electrical system for continuous draw only. Spin-up transient kills undersized systems.

Common Power Problems

1. Battery Sag

Symptoms: Gyro starts, reaches partial speed, then faults on low voltage. House electronics flicker or reset.

Cause: Battery capacity too small for spin-up transient
Check: Battery voltage under 60A load (should stay >11.5V for 12V systems)
Fix: Upgrade to larger AGM bank or add lithium with BMS rated for peak discharge

2. Alternator Undersized

Symptoms: Battery never reaches full charge. Gyro works when engines are at cruise but faults at idle.

Cause: Standard alternator (60–90A) cannot cover gyro + house loads + charging
Check: Alternator output at 800 RPM idle vs. total vessel load
Fix: Upgrade to high-output alternator (160A+) or add secondary alternator dedicated to gyro/house

3. Genset Brownout (AC Units)

Symptoms: Gyro spool-up causes genset voltage to dip, AVR triggers fault, or other AC loads drop out.

Cause: Genset sized for continuous load, not 3x spin-up transient
Check: Genset transient response spec (voltage recovery time under 100% load step)
Fix: Add soft-start module or VFD to limit inrush to <30% of genset rating

4. 24V Conversion Errors

Symptoms: New 24V gyro on originally 12V vessel. Converter overheats, voltage unstable, or 12V accessories fail.

Cause: DC-DC converter undersized, poorly located (heat), or sharing ground with 12V system
Check: Converter efficiency at rated load (typically 85–92%). Account for heat loss.
Fix: Dedicated 24V battery bank with dedicated 24V alternator or converter rated at 2x expected load

Electrical Audit Checklist

Before any installation, retrofit, or relocation, we audit:

Battery bank: chemistry, age, capacity, internal resistance
Alternator: output curve from idle to max RPM, regulator type (internal vs. external)
Wire sizing: gauge, run length, termination quality, voltage drop <3%
Grounding: single-point ground reference, no ground loops with electronics
Genset (if AC): kW rating, transient response, AVR stability, load step capability
Converter (if 24V): efficiency, heat dissipation, input/output isolation
Monitoring: shunt-based amp counting, voltage trending, fault logging

            Real-World Example: A 35' center console with SK6 and twin 300HP outboards had a 90A alternator. At idle (700 RPM), alternator output was 28A. Gyro spin-up drew 70A. Result: battery sagged to 10.2V, gyro faulted, and chartplotter rebooted. Fix: 180A high-output alternator + 2x Group 31 AGM bank.
        