Marine Power Systems: Lithium House Banks, Charging & Expert Support
A complete marine power system has four parts working together: a lithium house bank sized to your actual loads, a charging strategy that works both at anchor and underway, monitoring so you always know your state of charge, and correctly sized protection and fusing.
Access Power Solutions builds these as matched kits at three levels, and reviews every marine charging upgrade before it ships.
Who is this for?
- Coastal and weekend cruisers — you want lights, refrigeration and electronics to last the weekend without running the engine.
- Liveaboards at anchor — the boat is home, and marina fees are the thing you are trying to avoid. Power has to work every day, not just on good days.
- Long-distance cruisers — passages, larger banks and multiple charging sources that all have to agree with each other.
What does a complete marine power system include?
Storage (a LiFePO4 house bank, typically built from Victron 12V 200Ah NG Smart batteries), charging (shore power, solar, and alternator charging through a smart regulator such as the ARCO Zeus), monitoring (a Victron BMV-702 at starter level, Cerbo GX with a GX Touch display on larger systems), and protection (battery management, a BatteryProtect disconnect, and correctly rated fusing and busbars).
Which kit level do I need?
Starter — monitoring and visibility
2 × 12V 200Ah NG lithium
Standard shore / engine charging
BMV-702
Talk to a power professional
Mid-Level — better charging reliability
3 × 12V 200Ah NG lithium
ARCO Zeus regulator + high-output alternator + shunt
Cerbo GX + GX Touch 50
System review recommended
Advanced — cruising / complex systems
4 × 12V 200Ah NG lithium
Zeus + A275L alternator + integrated inverter/charger
Cerbo GX + GX Touch 70
Custom design required
Component sizing follows APS engineering revision v0.2, approved by APS engineering. Solar panel models are being confirmed with our vendor.
Why do boat owners upgrade charging before capacity?
Because a bigger bank you cannot refill just cycles half-empty. On a boat the engine is often the fastest charging source available, but a stock alternator cannot safely charge lithium at full output for long. That is why the mid-level path adds external regulation rather than simply more batteries — storage, charging and loads have to be sized together.
Upgrading a boat you already own?
Before changing hardware, work through what the upgrade actually touches — loads, bank sizing, recharging, monitoring, solar, and protection.
Frequently asked questions
Usually yes, and it is our most popular marine upgrade — but it is a system change, not a battery swap. Charging sources (alternator, shore charger, solar controller) all need lithium-compatible profiles, and the bank needs proper battery management and protection. We review the whole system before recommending anything.
That is exactly what these systems are for. A correctly sized lithium bank with solar keeps refrigeration, lighting and electronics running at anchor; the engine or shore power tops the bank back up when you move.
Yes — without one you are guessing. A shunt-based monitor measures current in and out so you know real state of charge rather than voltage, which is misleading on lithium.
Find your marine system
Marine charging upgrades are never sold without a review: alternator, regulator and battery chemistry have to be validated together. Start with the Power Guide, or talk to a power professional.