Battery Troubleshooting Guide

Use this guide when batteries are not behaving as expected, even if no fault code is displayed.
This page focuses on real-world symptoms and fast diagnosis.

Quick Start

Select the symptom that best matches the issue:

Battery Not Charging

What you’ll see

  • SOC stays low
  • Inverter shows grid/PV available but battery idle
  • No active battery fault code

Most common causes

  • Charging disabled in inverter settings
  • Battery charge current set too low
  • Battery at temperature limit
  • Grid/PV priority settings blocking charge

Quick checks (start here)

  • Charging disabled in inverter settings
  • Battery charge current set too low
  • Battery at temperature limit
  • Grid/PV priority settings blocking charge

Advanced checks

  • Check battery BMS limits in monitoring app
  • Confirm inverter firmware supports battery model
  • Verify correct battery protocol selected

See brand-specific fault codes here

Fault Codes

Battery Not Discharging

What you’ll see

  • Loads drawing power from grid
  • Battery SOC high but no discharge

Most common causes

  • Discharge disabled
  • Minimum SOC set too high
  • Time-of-use schedule blocking discharge
  • EPS not enabled

Quick checks (start here)

  • Enable battery discharge
  • Lower minimum SOC
  • Disable TOU temporarily for testing
  • Confirm EPS/backup mode enabled (if applicable)

Battery Not Communicating

What you’ll see

  • “BMS fault” or “Battery offline”
  • SOC stuck at 0% or 100%
  • Inverter does not detect battery

Most common causes

  • Wrong communication port
  • Incorrect CAN/RS485 cable
  • Wrong protocol selected
  • Incorrect DIP switch settings
  • Power-up sequence incorrect

Quick checks (start here)

  • Confirm correct CAN/RS485 port
  • Check cable type (straight vs crossover)
  • Select correct battery protocol
  • Power cycle: Battery → Inverter

Advanced checks

  • Firmware compatibility (battery & inverter)

  • Termination resistor installed correctly

  • Test with known working cable

See brand-specific fault codes here

Fault Codes

SOC Incorrect or Jumping

What you’ll see

  • “BMS fault” or “Battery offline”
  • SOC stuck at 0% or 100%
  • Inverter does not detect battery

Most common causes

  • Battery not calibrated

  • Partial charge cycles only

  • Firmware mismatch

  • Parallel battery imbalance

Quick checks (start here)

  • Perform full charge cycle to 100%
  • Allow battery to rest at full SOC
  • Update firmware if available
  • Balance parallel batteries

Battery Online but No Power Flow

What you’ll see

  • Battery shows connected

  • Zero charge or discharge current

Most common causes

  • Battery in protection mode

  • Charge/discharge limits active

  • Inverter operating mode conflict

Quick checks (start here)

  • Check BMS limits in monitoring app

  • Verify inverter operating mode

  • Restart system following correct sequence

Battery Trips or Shuts Down Randomly

What you’ll see

  • “BMS fault” or “Battery offline”
  • SOC stuck at 0% or 100%
  • Inverter does not detect battery

Immediate actions

  • Inspect all DC terminals
  • Check cable sizing vs current
  • Verify ventilation and spacing

Safety Warnings

  • Always isolate DC before disconnecting

  • Never hot-plug communication cables

  • Follow manufacturer torque specs