Battery bank sizing
Size lithium or AGM battery banks against realistic onboard load profiles and autonomy targets.
MarinePower.app
Marine power calculator.
Battery, cable, charging.
An advanced online calculator for marine electrical systems. MarinePower.app lets boat owners, engineers and yacht professionals accurately size battery banks, inverters, cabling, shore power, generators and solar systems — in one place.
Features
Every calculation the DC system needs.
Inverter sizing
Match inverter capacity to continuous, peak and surge loads across galley, HVAC and entertainment systems.
Shore power calculations
Check shore power draw, breaker sizing and voltage drop for Mediterranean and Caribbean marinas.
Generator sizing
Right-size gensets against actual load duration, avoiding low-load running and unnecessary hours.
Marine cable sizing
Cross-sections and voltage drop over run length, checked against ABYC and ISO 10133/13297 practice.
Charging systems
Alternator, shore charger and DC-DC — matched to battery chemistry, bank size and use case.
Solar power systems
Panel arrays, MPPT selection and daily yield estimates for realistic marine solar contribution.
Power requirements
Aggregate consumption, load duration and daily energy budgets — all in one place.
Behind the calculations
Lithium, AGM, charging and cable sizing — done right.
MarinePower.app is grounded in the same day-to-day marine electrical consultancy that MS Ocean provides to yachts and commercial vessels. The topics below sit under the calculators.
Lithium batteries
Sizing, BMS integration and safe DC architecture for LiFePO4 house banks.
AGM batteries
Traditional AGM banks — bulk/absorption/float profiles and realistic depth-of-discharge planning.
Charging systems
Coordinated alternator, shore and solar charging matched to bank chemistry and daily energy budget.
Marine electrical calculations
Cable sizing, voltage drop, breaker selection and DC distribution — checked against recognised marine standards.
For deeper reading see our Insights — including sizing a lithium battery bank and marine cable sizing.
Benefits
Better decisions,
earlier in the project.
Purpose-built for marine work — accurate, fast, and made to be shared with the people paying the bill.
Save engineering hours
Replace spreadsheets and back-of-envelope maths with a purpose-built tool.
Reduce specification risk
Catch undersized cabling and under-scoped battery banks before installation.
Move faster with owners
Turn technical decisions into clear, shareable outputs owners can sign off.
Try it now
Size your next system in minutes.
Web-based No install Built for marine use