Direct answer
Runtime is comparable only when the product revision, battery, starting charge, volume, audio content, codec/input, wireless conditions, temperature, indicator behavior and stop rule are controlled and recorded.
Test sequence
- Identify the unit, firmware, battery/cell and charger.
- Charge under the documented method and record the rest period.
- Set the source, codec/input, content, EQ/mode and measured volume condition.
- Record temperature, wireless conditions and any active lights or functions.
- Log time, voltage/indicator events and the predefined stop condition.
- Repeat enough units/runs to report variation, not only the best result.
Stop rules
Functional stop
Audio stops or the unit shuts down under the defined mode.
Quality stop
Output falls below a predefined usable threshold.
Protection stop
Low-battery protection or another safety control activates.
The chosen rule must be stated because different stop rules can produce different runtime claims.
Evidence boundary: This page provides a decision framework, not a statement that a selected product has passed a test or holds a certificate. Confirm model-specific specifications, reports, samples and commercial terms in current written documents.