Marine Lithium Battery Glossary
Plain-English glossary of marine lithium battery, solar, inverter and boat electrical terms.
Ah: Amp-hour, a unit of charge capacity.
Alternator: Engine-driven electrical generator used to charge batteries and power DC loads.
BMS: Battery Management System.
Busbar: Conductive distribution point for multiple high-current circuits.
C-rate: Charge or discharge current expressed relative to battery capacity.
CAN bus: Digital communication network used by batteries, chargers and monitoring systems.
Cell: Individual electrochemical unit inside a battery.
DC-DC charger: Device that converts and regulates DC power from one DC source to another battery.
Depth of discharge, DoD: Percentage of battery capacity removed.
Fuse interrupt rating: Maximum fault current a fuse can safely interrupt under specified conditions.
Inverter: Converts DC power into AC power.
Inverter-charger: Combined inverter, charger and often transfer switch.
IP rating: Ingress-protection classification for solids and water.
kW: Kilowatt, 1,000 watts of power.
kWh: Kilowatt-hour, 1,000 watt-hours of energy.
LiFePO4: Lithium iron phosphate chemistry.
MPPT: Maximum Power Point Tracking solar controller.
Parallel: Battery connection that increases Ah while keeping voltage the same.
Series: Battery connection that increases voltage while keeping Ah the same.
Shunt: Precision low-resistance device used to measure current.
SoC: State of charge.
Voltage drop: Loss of voltage caused by resistance in wiring and connections.
Wh: Watt-hour, a unit of energy.
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.