Converting a Boat from AGM to Lithium
Convert an AGM house bank to LiFePO4 safely by reviewing alternator charging, shore power, solar, BMS, fuses, cabling and monitoring.
Do not start by removing the AGM batteries.
Start by mapping the boat.
Record every charge source
- alternator
- engine-driven external regulator
- solar
- MPPT controller
- shore charger
- inverter-charger
- generator
- wind generator
- hydro generator
- emergency combiner
Record every major load
- inverter
- windlass
- thruster
- fridge
- freezer
- autopilot
- pumps
- watermaker
- air conditioning
- electric cooking
Review
- cable sizes
- fuses
- battery switches
- busbars
- existing shunt
- AC charger lithium profile
- solar controller lithium profile
- alternator thermal limits
- engine-start isolation
- BMS alarm strategy
- battery location
- ventilation
- fire detection
The alternator is a common trap because a depleted lithium bank can continue demanding substantial current.
Apply this guidance to your boat
Use this page as one input to a vessel-specific plan. Record the actual equipment, cable runs, charging sources and operating pattern aboard before choosing hardware or changing the installation.
- Measure the real load and its operating time instead of relying on a label or a generic boat profile.
- Check every proposed current against the battery, BMS, protection, cable and connection limits.
- Confirm the result against current manufacturer instructions and the rules that apply to your vessel.
Work out your own numbers
Lithium vs Lead-Acid Payback CalculatorWork out how long a marine lithium battery bank takes to pay back its extra cost against AGM or lead-acid, using your own quotes and datasheet cycle life.How to Compare Marine Lithium BatteriesIndependent framework for comparing marine lithium batteries sold in Australia without relying on advertising claims.
Related pages
How to Choose the Right Marine Lithium BatteryCompare LiFePO4 boat batteries by energy, BMS current, IP rating, certification, warranty, communication, temperature and marine suitability.How to Compare Marine Lithium BatteriesIndependent framework for comparing marine lithium batteries sold in Australia without relying on advertising claims.Marine Lithium Battery Brands in AustraliaIndependent directory framework for marine LiFePO4 battery brands available in Australia, including specifications, BMS, warranty and marine features.Cheap vs Premium Marine Lithium BatteriesUnderstand what you may actually be paying for in a premium marine lithium battery: BMS, cells, case, support, IP rating and integration.Marine Lithium Battery Installation GuideUnderstand the full installation process for a LiFePO4 boat battery bank, including design, BMS, charging, fuses, cabling, monitoring and commissioning.Marine Lithium Battery Installation ChecklistDetailed pre-installation and commissioning checklist for a boat LiFePO4 electrical system.