People frequently search for battery charger error codes to identify connection issues, battery health problems, or internal charger faults. While some chargers use numerical codes, others use specific LED flashing patterns.

1. Schumacher Error Codes (Numerical)

These are among the most searched codes for consumer automotive chargers.

F01

Internal shorted cell in the battery.

F02

The charger cannot desulfate the battery (desulfation failed).

F03

The battery failed to reach full charge voltage, often due to charging a large battery on too low a current setting.

F04

Reverse polarity; the clamps are connected to the wrong terminals.

F05

The charger cannot keep the battery fully charged in "maintain mode".

F06

Thermal runaway detected; the battery is getting too hot.

2. NOCO Genius (LED Flashing Patterns)

NOCO chargers typically use LED signals instead of alphanumeric codes to communicate "Advanced Diagnostics".

Single Flash (Error & Standby LEDs)

The battery will not hold a charge.

Double Flash (Error & Standby LEDs)

Indicates a possible short circuit in the battery.

Triple Flash (Error & Standby LEDs)

Battery voltage is too high for the selected charging mode.

Red Error LED (Solid/Flashing)

Typically indicates reverse polarity or that the battery voltage is too low for detection.

Hot LED Flashing

Internal or external temperature is too high.

3. Victron Energy (Err Codes)

These codes are frequently searched for MPPT solar chargers and professional-grade units.

Err 2

Battery voltage is too high.

Err 14

Battery temperature is too low (charging stopped to prevent damage to LiFePO4 batteries).

Err 17

Controller has overheated despite output reduction.

Err 20

Maximum bulk-charging time has been exceeded.

Err 33

PV (solar panel) over-voltage.

4. Common EV Charger Faults

Users of electric vehicle (EV) charging stations often search for these standard fault indicators.

E001

Communication error between the charger and the vehicle.

E002

Overcurrent protection has been triggered.

E003

Ground fault (electrical leakage) detected.

E004

Overheating protection activated.