Forty years ago, the solid-state revolution, which gave us computers and a host of increasingly powerful electronic devices, reshaped boat energy systems in ways that have underpinned a remarkable transition from camping out to enjoying the comforts of home. Initially, this required an AC generator to be run long hours, and sometimes 24/7, often extraordinarily inefficiently and frequently with a duty cycle that was (and still is on many boats with generators) damaging to the generator engine.
Over the years, three technologies have fused to sideline the generator and today are fueling a new revolution in onboard energy systems.
These are DC-to-AC inverters, lithiumion batteries, and alternators with levels of output we could only dream about in the past. Inverters can now handle any AC load on a boat, including substantial air conditioning; lithium-ion batteries store the energy needed to power the inverters (and all other boat systems) for hours and sometimes days; and alternators recharge the batteries with limited engine run times, mostly when underway so no additional run time is required.
Inverters are well understood, and lithium-ion batteries are becoming more affordable and widespread—although many more installation issues need to be thought through and accommodated than with lead-acid batteries.
For now, I want to focus on the evolution of alternators.
The Pioneers
How many readers remember Dave Smead? A brilliant engineer, Dave’s many accomplishments include building the world’s first portable
