Consumer Electronics Battery Troubleshooting

I need a seasoned electronics professional to methodically test and troubleshoot a consumer-grade device that is showing persistent battery-related problems. The unit fails to hold charge consistently and occasionally shuts down without warning, so I want a clear diagnosis of the underlying circuitry and a practical repair or redesign recommendation.

Here is what I expect:
• Bench-level testing of the power stage, charging circuit, and protection ICs
• Identification of faulty components or design flaws causing the battery issue
• A concise report summarising test procedures, measured results (voltage, current draw, ripple, thermal behaviour), root-cause analysis, and proposed corrective measures
• Optional: firmware review if the fault points to power-management code interactions

You may use oscilloscopes, multimeters, electronic loads, battery analysers, and any other specialised tools you deem necessary. Deliver all findings in an editable document plus annotated schematics or scope captures where relevant. If replacement parts or layout changes are required, specify them clearly so I can authorise the next step quickly.

Timely communication, precise measurements, and evidence-based conclusions will be the key acceptance criteria for this engagement.