Conference Sessions Title: Predictive Replacement Strategy for Defibrillator Batteries: A Longitudinal Analysis of Zoll R Series Battery Longevity (2014–2025)

1. The importance of following the Zoll R series battery p.m. procedure.
2. Correct procedure for testing and reconditioning a Zoll R series battery pack.
3. View a 10 year study of Zoll R series battery testing results.

Title: Predictive Replacement Strategy for Defibrillator Batteries: A Longitudinal Analysis of Zoll R Series Battery Longevity (2014–2025)
Abstract: This paper outlines a data-driven justification for the preemptive replacement of 24 batteries within a fleet of 146 Zoll R series defibrillators. Based on eight years of historical performance data, a predictive maintenance model suggests that current units nearing critical age thresholds will likely fail before the 2027 preventive maintenance (PM) cycle. Preemptive replacement in May 2026 is recommended to maintain device readiness and patient safety.
1. Introduction
Defibrillators are life-critical medical devices requiring 100% operational readiness. The Zoll R series relies on rechargeable lithium-ion batteries, which exhibit predictable degradation over time. While industry standards often suggest a 5-year lifespan for similar Li ion components, real-world longevity varies based on usage and environmental factors. This study evaluates Renown Health’s specific failure rates to optimize the replacement cycle.
2. Methods
A longitudinal cohort study was conducted on 146 R series batteries. Annual testing and reconditioning have been performed every May since 2014. Failure rates were categorized by purchase year (vintage). Predictive analysis was applied to determine the probability of survival for the remaining units through the May 2026 to May 2027 window.
3. Results
Analysis of the provided .xlsx datasets revealed clear age-dependent failure trends:
• Cohort 2014 (n=19): 52.6% failure rate to date. 9 units remain in service.
• Cohort 2015 (n=32): 96.9% failure rate. Only 1 unit remains in service.
• Cohort 2016 (n=3): 100% failure rate observed.
• Cohort 2017 (n=28): 25% failure rate (7 units).
• Cohort 2019 (n=62): 12.9% failure rate (8 units).
• Cohorts 2021–2025 (n=99): 2% failure rate (2 units), indicating high reliability in newer units.
4. Discussion & Prediction
The data demonstrates that batteries exceeding 7 years of service (2014–2017 cohorts) enter a high-risk “wear-out” phase.
• Critical Risk: Based on the near-total failure of the 2015/2016 cohorts, it is statistically improbable that the remaining 2014 and 2015 units (10 total) will survive another 12 months.
• Projected Failures: We predict a 26% failure acceleration for the 2017 cohort and an additional 11% for the 2019 cohort before the 2027 PM cycle.
• Stability: Newer batteries (2021+) do not currently require intervention.
5. Conclusion
To prevent mid-cycle equipment downtime, I have ordered the immediate procurement of 24 replacement batteries for the May 2026 PM cycle. This proactive approach adheres to Predictive Maintenance (PdM) principles, significantly reducing the risk of device failure during emergency clinical use.

James Knight
Clinical Systems Engineer
Clinical Engineering