BYD Seagull Charge Drops When Parked: Smart Charging

BYD Seagull loses a little charge when parked: smart charging, not a leak

Scope: China-mainland 2026 Seagull; official website file 260317; PDF p. 105, "Low-voltage battery"

Where the energy goes

The manual explains that, when certain conditions are met, the traction battery smart-charges the low-voltage battery, so the displayed charge level or electric range may be lower when the car is started again after parking. This is a normal energy path described by the manufacturer: a parked car does not mean every system has stopped drawing power. A single change in the figures is not enough to prove the traction battery is damaged. ^[1]

Keep records you can compare

To judge whether a change is abnormal, record when parking started and ended, the starting charge level, the ambient temperature, whether the air conditioning was used remotely, and whether any low-voltage battery warning appeared. Records from similar durations and conditions are more useful to the workshop than subtracting two range figures taken under different conditions. This recording method is an editorial suggestion, not a manufacturer threshold for diagnosing a power drain. ^[1]

When to have it checked professionally

Smart charging only happens under certain conditions and cannot explain every loss of charge. If the car repeatedly fails to unlock, a low-voltage charge warning keeps appearing, or the change in charge clearly affects normal use, have a workshop check the low-voltage system and the vehicle as a whole. Do not pull fuses, disconnect power or remove the battery yourself to test the drain; this can alter the fault conditions and introduce electrical risk. ^[1]

Sources

[Source 1] BYD China official website: 2026 Seagull Owner's Manual (in Chinese) (public PDF on the official website)
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
Verified: 2026-10-03; page publication date not confirmed.

This article contains information-organising suggestions from the editorial team; it is not a manufacturer repair procedure.