Generator vs Shore Power Charging
6 min read · Updated
Owners often ask why the generator runs so much when shore power is available — or vice versa. The honest answer is that neither is universally 'better'. Each has a role, and the right strategy depends on the vessel, the itinerary and the battery chemistry.
Where shore power wins
In a marina berth with an adequate pedestal, shore power is quiet, cheap and low-maintenance. It also lets you run high-continuous loads (HVAC in the Mediterranean summer, for example) without cycling the bank.
Where a generator wins
At anchor and underway, the generator is the only high-power source. For lithium banks, running the generator hard for a short bulk absorption is far more efficient than long low-load hours — the classic mistake on legacy AGM installations.
Designing a hybrid strategy
The goal is to keep the bank in its healthy state-of-charge window with the fewest generator hours possible. That usually means a combination of shore power in port, solar and DC-DC charging underway, and short high-power generator runs at anchor to top up.
Need advice on your own vessel? Read more about our services, explore MarinePower.app or request a consultation.