LG RESU Battery Deep Discharge Recovery – Troubleshooting... | solardiagnostics.org

Technical Background:

Deep discharge occurs when the battery voltage falls below a critical threshold, often triggered by prolonged high loads or insufficient solar production. The inverter monitors battery voltage and can initiate a fault condition to protect both the battery and the inverter. This is typically managed through the battery management system (BMS), which assesses parameters such as insulation resistance (RISO) and ground faults. If the BMS detects conditions that could lead to battery damage, it will prevent further discharge and may trigger alerts to the user.

Symptoms:

Homeowners may observe the following visual indicators: the LED indicators on the LG RESU battery may flash red or remain off, indicating a fault condition. Additionally, monitoring applications may display alerts related to battery status, such as 'Battery Discharged' or 'Battery Fault.' System performance may also drop, with a noticeable decrease in energy output from the solar array.

Possible Causes:

The battery was subjected to prolonged periods of low voltage due to excessive load or insufficient solar production.
Inverter settings may not have been configured to prevent deep discharge, leading to battery depletion beyond safe levels.
A malfunction in the battery management system (BMS) failed to detect and mitigate deep discharge conditions.
Ineffective insulation resistance (RISO) measurements indicated poor insulation, causing the inverter to trigger a fault to protect the system.
Ground faults in the system may have caused unexpected current draw, leading to battery over-discharge.
External factors such as extreme temperatures may have impacted battery performance and led to deep discharge conditions.

Solution:

1

Disconnect the battery from the inverter using an MC4 disconnect tool to ensure safety during the recovery process.
2

Use a multimeter to measure the voltage of the battery. If the voltage is below the manufacturer's specified recovery threshold, proceed to the next step.
3

Connect the battery to a compatible charger or the inverter’s recovery mode, if available, to initiate a controlled charge cycle.
4

Monitor the voltage levels closely during charging to ensure they rise steadily without exceeding the maximum voltage limit.
5

Once the battery voltage reaches the acceptable range, reconnect it to the inverter and check for error codes or alerts in the monitoring app.
6

Perform a string voltage verification to ensure that all components are functioning properly and that no additional faults are present.
7

Reconfigure inverter settings to prevent future deep discharge situations by setting appropriate low voltage disconnect parameters.

Safety Warning:

Always consult a licensed electrician or certified solar installer for troubleshooting and repairs to ensure compliance with safety standards and local codes.

Prevention:

To avoid deep discharge in the future, regularly monitor battery performance through the inverter's app, ensuring that the system is configured to prevent discharge below the manufacturer's recommended voltage. Schedule routine maintenance checks to assess the BMS and inverter settings, and consider upgrading to a more robust energy management system if frequent deep discharge events occur.

Frequently Asked Questions

•What causes deep discharge in batteries?

Deep discharge occurs when a battery is drained below its recommended voltage level, which can damage its cells. This can happen due to prolonged inactivity or excessive load.

•How can I prevent deep discharge in my battery?

To prevent deep discharge, regularly monitor battery levels and set up alerts for low voltage. Additionally, ensure proper usage and maintenance of the battery system.

LG RESU Battery Deep Discharge Recovery – Troubleshooting & Technical Fix Guide

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention:

Frequently Asked Questions

•What causes deep discharge in batteries?

•How can I prevent deep discharge in my battery?

Related questions

Technical Background:

Symptoms:

Possible Causes:

Solution:

Safety Warning:

Prevention: