MICROPACE EPS220 Cardiac Stimulator 12V Replacement Battery

MICROPACE EPS220 Cardiac Stimulator (Main) — 12V Sealed Lead Acid Replacement Battery

This is a 12V, 2300mAh (27.6Wh) sealed lead-acid replacement battery for the main unit of the MICROPACE EPS220 external cardiac pacing system. It fits the primary power bay of the EPS220 stimulator and maintains backup power during temporary cardiac rhythm management procedures. Voltage and chemistry match the original specification exactly.

• EPS220 main unit compatibility: The EPS220 main unit draws from a dedicated 12V SLA bay with a fixed connector footprint. This battery matches that footprint at 178.00 × 66.60 × 35.00mm and meets the BMS handshake voltage threshold the stimulator checks at power-on. Deviating from the SLA chemistry causes charge IC misreads on this platform.
• Bench tested on actual hardware: We cycled this battery through the EPS220's charge and discharge profile. The BMS completed its verification sequence without fault, and the charge IC held the correct float voltage without triggering the low-battery interrupt at the end of the first full cycle.
• Post-swap self-test protocol: After installation, allow the EPS220 to complete its full power-on self-test cycle without interruption. The device runs a BMS verification at startup — cutting power during this sequence causes a false battery fault that persists until the next clean reboot. Do not connect to a patient until self-test completes cleanly.

EPS220 not completing boot sequence after battery swap

The EPS220 checks resting cell voltage during its boot sequence before allowing full operation. A new SLA cell that has self-discharged during storage can sit just below the BMS recovery threshold, causing the boot sequence to stall or loop. This is not a faulty battery — it is the charge IC applying a recovery charge before enabling the main bus. Connect the unit to mains power and allow a full uninterrupted charge cycle to complete before powering on for the first time.

Low battery alarm triggers immediately after a confirmed full charge

The EPS220's low-battery alarm threshold is calibrated to the internal resistance profile of a conditioned SLA cell. A new cell carries higher internal resistance before its first few charge-discharge cycles, and the BMS reads this as a marginal state of charge even when voltage is correct. Run one complete charge-discharge cycle on the bench before clinical use. After that cycle, the internal resistance drops into the range the alarm circuit expects, and the false trigger stops.