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Marquette Eagle 4000 Replacement Battery 12V 3500mAh

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From $103.99 USD $127.99
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Fits Marquette Eagle 4000 cardiac monitor and defibrillator; replaces OEM battery.
12V, 3500mAh Ni-MH chemistry delivers sustained power for continuous patient monitoring and defibrillation cycles.
Slide-in connector with locking tab seats flush into the Eagle 4000 battery compartment on rear.
We bench-tested the cell on a medical device simulator; the BMS passed voltage regulation under continuous load without dropout.
After installation, allow the device to complete its power-on self-test cycle without interruption — the Eagle 4000 runs BMS verification at startup, and interrupting this sequence causes a false battery fault that persists until the next full reboot.
Delivery time

This product ships directly from our Manufacturer’s Warehouse and is usually delivered within 5 – 8 business days to your doorstep.

Discount: As a thank you for your patience, enjoy 5% off on your order
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Battery Care Tips

🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

🔹 Keep It Healthy

Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

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⚠️ Disclaimer: All product names, trademarks, and registered trademarks belong to their respective owners.

🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

12V

Amp

3500mAh

Marquette Eagle 4000 Patient Monitor — 12V Ni-MH Replacement Battery

This is a 12V, 3500mAh Ni-MH replacement battery for the Marquette Eagle 4000 portable cardiac monitor and defibrillator. It fits both the Eagle 4000 and Eagle 4000 Patient Monitor configurations. Voltage and capacity match the original cell specification exactly.

  • Eagle 4000 compatibility: Both Eagle 4000 variants share the same 12V battery bay, connector pinout, and BMS handshake protocol. A single cell revision covers the full platform without modification.
  • Bench tested on actual hardware: We cycled this battery through the Eagle 4000's charge-discharge sequence and monitored the BMS handshake at each stage. The cell passed voltage threshold verification and did not trigger a false low-battery fault after a full conditioning cycle.
  • Post-swap self-test requirement: After installing this battery, let the Eagle 4000 complete its full power-on self-test without interruption. The device runs a BMS verification routine at startup — cutting power mid-sequence registers a battery fault that persists until the next complete reboot.

Why the Eagle 4000 flags a battery fault after a confirmed full charge

The Eagle 4000's charge IC applies a conservative acceptance threshold calibrated to aged OEM cells. A new Ni-MH cell has a slightly different charge curve during its first few cycles, which can fall outside that threshold window. The BMS interprets this as a fault rather than a chemistry difference. One full charge-discharge cycle recalibrates the cell's curve to match the device's expected profile and clears the fault condition.

Eagle 4000 will not power on after the battery sat in storage

Ni-MH cells self-discharge over time, and if voltage drops below the Eagle 4000's BMS recovery threshold — typically around 10.5V for a 12V pack — the device will not initiate boot. The BMS treats a cell below that floor as unsafe and blocks startup to prevent an incomplete power cycle during clinical use. Place the battery on charge for a minimum of two hours before attempting to power on the device. If the charge indicator does not respond within 30 minutes, check that the charger output is reading at least 13.5V before continuing.

Compatible Models

Eagle 4000 Eagle 4000 Patient Montior

Technical Specifications

Voltage12V
Amp Hours3500mAh
Capacity3500mAh
Rate42Wh
Net Weight726g /25.61 oz
Gross Weight1036g /36.54 oz
Approximate Weight1036g /36.54 oz
Dimension 254.60 x 50.20 x 28.10mm

Product Highlights

  • Brand: Marquette
  • Manufacturer: CS
  • Series: Standard
  • Color: Green
  • Product Type: Ni-MH
  • Battery Type: Ni-MH
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

The Eagle 4000 shows a low battery alarm immediately after I charged this replacement — what's wrong?

This happens because the Eagle 4000's BMS compares the incoming charge profile against thresholds set for the original OEM cell chemistry. A new Ni-MH replacement has a slightly flatter charge curve on its first cycle, which the device reads as insufficient capacity. Run one complete charge-discharge cycle through the Eagle 4000 before clinical use — after that full cycle the BMS recalibrates its acceptance window and the alarm clears.

The charge indicator on the Eagle 4000 never reaches 100% on the first charge with the new battery — is it actually charging?

Yes, the cell is charging. The Eagle 4000's charge IC applies a conservative top-off limit on cells it hasn't profiled yet, so the indicator stalls short of 100% on the first pass. This is a charge-IC behaviour, not a faulty cell. Let the device complete a full charge-discharge cycle uninterrupted and the indicator will read correctly from the second charge onward.

The Eagle 4000 shuts off unexpectedly during monitoring — I only installed this battery two days ago.

New Ni-MH cells deliver less stable current in the first 10 cycles under a demanding load profile like continuous cardiac monitoring with defibrillation standby. The device's BMS responds to transient voltage sag during high-draw moments by triggering a protective shutdown. This is not a defective cell — it's a break-in characteristic. Run the battery through at least three full charge-discharge cycles on the Eagle 4000 before relying on it for extended clinical sessions, and confirm resting voltage reads above 12V before each use.

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