Fault

18

Battery Under Voltage Alarm.

4 Devices that report this code

What does the 18 error code mean?

18 on a Felicity unit indicates: Battery Under Voltage Alarm.. It is a fault-severity event that can appear on 4 different devices in the Felicity catalog. The same code may have slightly different recommended fixes depending on the device — the per-device sections below show the exact wording from each device's official manual.

This is a fault-severity code

Fault codes stop normal operation but the unit may attempt to recover. Common causes are out-of-range conditions (voltage, current, temperature) that require checking inputs and outputs before restart.

What triggers this code

18 is triggered when the unit's protection or monitoring logic detects the specific condition described above. The exact trigger depends on the device — see the per-device sections for the official manual entry for each.

IVGM5KL-P1G1Inverter↗ view on device
18Battery Under Voltage Alarm.Fault
Description

Battery voltage is too low, the battery should be charged.

Recommended fix

1. Restart the system 2~3 times; 2. if the fault still exists, please contact us for help.

Source:Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf · page 51Felicitysolar IVGM Series Hybrid inverter Instruction Manual.pdf · page 53
LUX-S-1600LG01Battery↗ view on device
18SampSensor is error.Fault
Description

Fault event: sampling sensor (current/voltage sensing circuit) error.

Recommended fix

Restart the unit. if the error persists, contact the repair center.

Source:LUX-S-1600LG01.pdf · page 22
LUX-Y-48100HG01Battery↗ view on device
18Relay Adhesion Fault.Critical
Description

Main relay contacts have welded/stuck (relay adhesion).

Recommended fix

Restart, if the fault still exists, contact our engineer.

Source:LUX-Y-48100HG01-Lithium-Battery-User-Guide.pdf · page 20
LUX-Y-48100HG01MNBattery↗ view on device
18Relay Adhesion Fault.Fault
Description

Relay Adhesion Fault.

Source:LUX-Y-48100HG01MN User manual 358-S010025-03 0325(V2.0).pdf · page 27

Frequently asked about 18

What is the 18 error on Felicity?
18 on a Felicity unit means: Battery Under Voltage Alarm.. It can appear on 4 different devices in the Felicity catalog. The cause and recommended fix are listed for each device on this page.
Can I clear the 18 code myself?
It depends on the severity. Warning-level codes can usually be cleared by following the recommended fix. Fault and critical codes often require checking the source condition first; if the code returns immediately after restart, escalate to authorized service.
Is the 18 fix the same on every device?
The cause is consistent — it's the same protection logic. The exact fix wording can differ per device because each official manual addresses model-specific context (input ranges, parallel-config notes, firmware revisions). Use the per-device section that matches your unit.
Where does this information come from?
Every entry is sourced directly from the official Felicity user manual for the affected device. The "Source" line at the bottom of each device's section shows the manual filename and page number.

Compiled from official Felicity user manuals. Always consult your device manual and a qualified technician before performing repairs.