BYD Battery Warranty: What's Covered, What 70% Means and What a New Pack Costs

What the battery warranty covers

It covers the high-voltage traction battery against manufacturing defects and against capacity falling below 70% SOH within the term. The drive unit (motor and controller) has its own 8-year cover in the UK and Australia. Plug-in hybrids — the DM-i models and the Shark 6 — also get an 8-year high-voltage battery warranty. It does not cover the 12-volt battery, which is a service item with much shorter cover, or damage from accidents, flooding or misuse.

What 70% state of health means in practice

SOH compares the battery's usable capacity today with its capacity when new. At 70%, a car that covered 400 km on a charge when new would manage about 280 km. If the pack falls below 70% before the warranty ends, BYD repairs or replaces it; loss above that line is treated as normal ageing. Most BYDs don't show SOH on the dashboard — a dealer reads it with diagnostic equipment, and some owners use an OBD2 scanner and an app.

How fast do BYD batteries degrade?

The Blade battery uses LFP chemistry, which generally ages slowly. One Australian owner test of a 2024 Seal measured about 95% SOH after roughly 50,000 km, and owner reports for first-generation Blade packs commonly cite 3–5% loss after around 100,000 km. These are individual results, not BYD data: heat, frequent DC fast charging and long periods sitting at 100% all speed up ageing.

How much does a BYD battery replacement cost?

BYD doesn't publish replacement prices, and a warranty replacement costs the owner nothing. Out of warranty, reported quotes are high: in Thailand in 2023 a service centre quoted about 1.1 million baht (around US$31,700) for a new standard-range Atto 3 pack after an accident, and in Brazil workshops estimated R$60,000–80,000 for a new Dolphin pack in 2025. A full pack can cost a large share of the car's value — which is why battery history matters so much on a used BYD.

BYD's lifetime cell warranty in China

In March 2026 BYD announced a lifetime warranty on the cells of its second-generation Blade battery in China. It covers the cells, not necessarily the rest of the pack (battery management, cooling and wiring), and BYD has not confirmed it for the UK or Australia. Outside China, treat the 8-year terms above as what applies unless a dealer confirms otherwise in writing.

Buying a used BYD: protect yourself

The 8 years run from the car's first delivery, not from the day you buy it, so ask a BYD dealer to confirm the start date from the VIN. Ask for a dealer battery health report, the service history and proof of any battery-related recall work. Be careful with imports: a privately imported BYD may have no local battery cover at all.

• How to check a BYD's battery health →
• Full BYD warranty: UK vs Australia →