Cummins Onan · HGLAA and compatible controllers; verify model applicability

Code 29Battery over voltage

Battery voltage exceeded the inverter/controller protection limit.

Published by RV Fault Finder · Independent referencePrimary source checked August 2026How this guide is researched →

What it means

Plain-English answer

The generator control saw excessive DC supply voltage. A charging-system, battery-bank, or connection problem may be present.

Owner-safe checks

What to check first

01
Turn the generator off.
02
Confirm the RV battery-bank voltage and configuration match the manufacturer specification.
03
Disconnect an external charger only through its normal safe shutdown procedure.

Safety boundary

Stop and call a technician when

A battery is hot, swollen, leaking, or smells of sulfur.
Voltage remains high or the code returns.

Primary reference

Check the exact manual

Applicability: HGLAA and compatible controllers; verify model applicability. The data plate and specification letter determine which procedure is correct.

Open Cummins Onan operator manual ↗Source reviewed August 2026