Marine Lithium Battery Not Charging
Diagnose a LiFePO4 house bank that will not charge from solar, alternator, shore power or generator.
Check in this order:
- Is the BMS allowing charge?
- Is battery temperature within allowed range?
- Is the charger powered?
- Is the charger configured for lithium?
- Is the fuse intact?
- Is the isolator on?
- Is there voltage at charger input?
- Is there voltage at charger output?
- Is the bank already near the configured charge limit?
- Has a cell reached high-voltage protection?
- Is CAN communication healthy?
- Is a remote-enable wire disabling the charger?
Do not bypass the BMS to "test whether it charges".
Diagnose before replacing parts
A shutdown or low-output symptom can begin in the battery, charging source, protection, cable path, monitor configuration or the load itself. Record evidence before resetting equipment so the original cause is not lost.
- Capture alarms, BMS history, state of charge, voltage at the battery and voltage at the affected equipment.
- Inspect for heat, looseness, corrosion, damage or water ingress before attempting another high-current test.
- Stop and isolate the system if there is swelling, unusual heat, odour, smoke, damaged cabling or repeated protection operation.
Related pages
Marine Lithium Battery MaintenanceMaintain a boat LiFePO4 bank by checking terminals, BMS history, charging, temperature, corrosion, balance and physical installation.BMS Shutdown TroubleshootingDiagnose common causes of marine lithium BMS shutdown including overload, low voltage, high voltage, heat, cold and current imbalance.Alternator Overheating After a Lithium ConversionUnderstand why alternators can overheat charging LiFePO4 banks and how current limiting, temperature sensing and regulation help.Boat Solar Not Charging Lithium Batteries ProperlyDiagnose low solar output on a yacht using LiFePO4 batteries and MPPT controllers.Marine Inverter Shutdown TroubleshootingDiagnose inverter trips caused by low voltage, BMS current limits, cable voltage drop, surge loads and overheating.Storing Marine Lithium BatteriesStore a marine lithium battery safely during winter, haul-out or long periods away from the boat.