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Numerous system voltages on the same Boat?? | Ask The Expert with NIGEL CALDER
2 May 2026 · 3 min · 1K views
Nigel Calder explains boat electrical systems in cabin
What this video covers
A 1983 Harris with mixed 12V, 24V, and 32V electrical systems — where the two engines each run on a 32V bank and one 32V bank doubles as the house battery — prompts the question of whether a single 48V lithium-ion battery in each engine room could replace the whole arrangement.▶ 0:38 Nigel Calder explains that the 32V standard is rare on boats and likely derived from a railway industry specification.▶ 1:03 Dropping a 48V system in without a full rewire is not viable: DC-to-DC converters would be needed to step down to both 24V and 32V, and a programmable converter to 32V is difficult to source.▶ 1:10 More critically, no DC-to-DC converter is large enough to supply the cranking current needed to start an engine, so a dedicated 32V cranking bank must remain regardless.▶ 1:46 Using lithium-ion for engine starting requires a battery specifically rated and designed for cranking — and it would still be the wrong voltage.▶ 2:25 The practical choice is either a substantial rewire to bring the boat to a single modern voltage standard or retaining the existing multi-voltage setup and adding 48V on top, which only introduces a fourth voltage rather than simplifying anything.▶ 2:02
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