BYD Seagull Battery Warning Lights: Overheat vs Fault

BYD Seagull battery overheat and fault lights: two warnings, not one diagnosis

Scope: based only on the 2026 Seagull owner's manual identified by its file name on BYD's official China website (file ID 260317; the current official PDF has 354 physical pages). The file-name date and PDF metadata are not treated as the publication date, and the exact publication date is unknown; the manual's foreword says asterisked features apply only to some configurations, and the actual vehicle, the version supplied with it and the market must be checked. This article covers only how owners recognise the two warnings and hand over to professionals; it does not diagnose faulty parts or give procedures for the battery casing, circuits, firefighting or accident rescue.

The two lights mean different things in the manual

When you see a battery icon, first check the exact name on the instrument cluster, when it came on and whether it stays on, rather than recording every warning as "battery broken". Physical page 42 of this Seagull manual explains that the traction battery overheat warning light means the temperature is too high and the car needs to stop and cool down; the separate traction battery fault warning light comes on briefly when the car enters "OK" mode and goes out after a few seconds if the self-check is normal, but may come on again or stay on if the system is abnormal. If it stays on or comes on intermittently while driving, contact an authorised BYD service centre as soon as possible. Overheating and a system fault may occur together, but neither light can stand in for the other, and a single light is no basis for deciding that a cell, a controller or the whole battery needs replacing. ^[1]

Driving conditions explain the circumstances, not the fault

The manual lists situations that may cause overheating, such as climbing hills for a long time in hot weather, and frequent hard acceleration and braking in congestion. Recording the ambient temperature, the road, the exact cluster message, how long it lasted and whether power was limited helps service staff review it; but these scenarios cannot prove that a particular car's warning is just "normal in hot weather". If an overheat warning appears, stop safely and let it cool as the manual says; if the fault light stays on after the self-check, comes on again or comes on while driving, contact an authorised service centre as soon as possible. Do not keep climbing, accelerating repeatedly or waiting for the other light to come on just to tell the two apart. If the warning doesn't clear after stopping, or the car behaves abnormally, stop trying to work it out yourself and ask for professional help. ^[1]

Accidents, smoke and electrical parts have stricter limits

The triage suggestions for normal warning lights do not cover suspected collision damage. The manual's accident section states that the car carries high-voltage electrical hazards, and that owners must not open, move or alter the battery casing or related connectors; people should keep away from orange cables and high-voltage parts, and related work should go to an authorised service centre. If after a collision there is an acidic smell, visible liquid or smoke from the battery area, move away from the car and contact professional rescue immediately; do not treat this as ordinary overheating and wait for it to cool. The manual also gives separate warnings about using water on a fire and about skin contact with leaked fluid; "using water on a fire carries a risk of electric shock" must not be misread as a ban on rinsing skin that has touched leaked fluid. This article does not teach owners to deal with fires or leaks. ^[1]

Sources

[Source 1] BYD Auto Industry Co., Ltd.: BYD China official website: 2026 Seagull Owner's Manual (in Chinese) (file 260317)
https://www.byd.com/material/domestic-official/user-manual/ocean/2026%E6%AC%BE%E6%B5%B7%E9%B8%A5%E7%94%A8%E6%88%B7%E6%89%8B%E5%86%8C260317.pdf
Publication date unknown; information checked at 2026-10-24T00:00:00Z, which is not the publication date.

Suggestions on record-keeping, requesting quotes, stopping attempts and handing over to a service provider are original editorial opinion, not a manufacturer procedure or diagnostic conclusion.