# LG RESU battery not charging: what it means and what to do

If your LG Chem RESU battery's ON light is lit but it never shows Charging or Discharging, LG's manual points first to the inverter: firmware versions and the inverter's battery settings. On SolarEdge systems, a battery state of energy below 10% that keeps falling while solar is producing is a related symptom. SolarEdge's first step for that is a battery self-test, which your installer runs.

## Common causes

- Outdated inverter or battery firmware.
- Incorrect battery settings in the inverter.
- Battery communication or wiring problems between the battery and inverter.

## Safe steps to try

1. **Check the battery lights** ON should be lit. Charging or Discharging should light while the battery is in use. If FAULT is lit, follow the FAULT light guide instead.
2. **Check your app** In your inverter's monitoring app, note the battery charge level, whether it changes over a sunny day, and any error such as 3x6B.

## When to call a professional

Contact your installer if the battery stays idle or keeps draining. LG's fixes are firmware updates, inverter battery settings and rechecking the wiring, all done at the equipment by a technician.

## Frequently asked questions

### Can low temperatures stop charging?

LG lists battery under temperature as one of the warning states that stop operation, which would also light the FAULT LED.

### Does my RESU need a firmware update?

LG's first troubleshooting step for a battery that will not charge or discharge is updating both inverter and battery firmware.

Canonical page: https://otovo.com/repair/lg/resu-not-charging