Dyson sells a V8 replacement battery. Weak suction can also come from clogged filters or tools, so a battery purchase depends on runtime in normal mode.
What to check before buying
Battery or blocked airflow
Dyson lists reduced runtime outside MAX mode among signs that the V8 battery may need replacement. A full bin, dirty filter, blocked tool or airway can instead reduce pickup while the motor still runs. Test runtime in normal power mode and inspect the airflow path before buying a cell.
Replacement parts
Dyson sells a V8 battery and shows how to install it. Match the machine’s variant and serial details when ordering; “V8-compatible” alone does not establish fit or quality. Filters, brush bars, seals and attachments can also wear. A brush that will not spin may be tangled or have a separate tool fault.
Used-vacuum condition
Inspect the bin latch, filters, charging behaviour and brush head. A new battery can extend use when the motor and tools are sound, but it will not fix a blocked airway or a damaged brush. If several assemblies are failing, compare their combined cost with a working V8 or refurbished alternative.