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Fukuda FX-7402 ECG Compatible Battery 9.6V 3800mAh

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Fits Fukuda FX-7402, Cardimax FX-7402, FCP-7311, and FCP-7401 electrocardiographs; replaces OEM part 8/HRY-4/3AFD.
9.6V 3800mAh Ni-MH chemistry delivers 36.48Wh to sustain continuous cardiac monitoring during portable ECG recording sessions.
Connector seats vertically into the battery slot with a locking tab that engages on insertion and requires slight downward pressure to release.
We bench-tested this cell across full charge-discharge cycles; the Fukuda BMS accepted the pack after the initial learning cycle completed.
Allow the device to run its complete power-on self-test without interruption after installation — the ECG's startup verification cycle confirms battery compatibility, and stopping this sequence triggers a false fault code that clears only on 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

9.6V

Amp

3800mAh

Fukuda FX-7402 / FCP-7401 Series — 9.6V Ni-MH Replacement Battery (8/HRY-4/3AFD)

This is a 9.6V 3800mAh Ni-MH battery for the Fukuda FX-7402, Cardimax FX-7402, FCP-7311, and FCP-7401 electrocardiograph machines, along with eight additional compatible models. It slots into the battery bay and restores portable ECG operation when AC power is unavailable. Voltage and chemistry match OEM spec exactly — 9.6V Ni-MH, 36.48Wh.

  • FX-7402 and FCP series compatibility: These Fukuda ECG models share the same 9.6V Ni-MH battery rail, connector pinout, and BMS handshake protocol. The charge IC in each device is calibrated to this chemistry — swapping to Li-ion is not supported and will trigger a persistent battery fault.
  • Bench tested on actual hardware: We cycled this cell through charge, standby, and load draw on the FX-7402 platform. The BMS completed its capacity verification without triggering a fault code, and the charge IC accepted the cell without requiring a manual reset.
  • Power-on self-test after installation: After fitting the new battery, allow the device to complete its full startup self-test without interruption. The ECG unit runs a BMS verification sequence at boot — cutting power mid-cycle causes a false battery fault that will persist until the next complete reboot.

Why the FX-7402 alarms low battery with a freshly charged replacement installed

The FX-7402 charge IC applies OEM-calibrated thresholds during its initial BMS verification pass. A new Ni-MH cell has not yet established its internal resistance baseline, so the device reads capacity conservatively and can trigger a low-battery alarm even after a confirmed full charge. This is not a faulty cell — it is the BMS treating an uncharacterised cell with the same caution it applies to a degraded one. Running one complete charge-discharge cycle allows the BMS to map the cell's actual capacity curve and clears the false alarm on subsequent boots.

Device not powering on after the battery sat in storage

Ni-MH cells self-discharge at roughly 1–2% per day at room temperature. A battery that has been in storage for several months can drop below the FX-7402's BMS recovery threshold — typically around 8.5V for a 9.6V pack — at which point the device refuses to power on as a protective measure. Connect the battery to a compatible Ni-MH charger externally before reinstalling, or leave the device on charge via AC for a minimum of two hours to allow the charge IC to recover the cell from its low-voltage state. Once the pack reads above the recovery threshold, normal power-on will resume.

Compatible Models

FX-7402 Cardimax FX-7402 FCP-7311 FCP-7401 FCP-7411 FCP-7431 FCP-7431S FX-7412 FX-7432 ECP-7600 ECP-7631 ECP-7641

Replaces Part Numbers

8/HRY-4/3AFD

Technical Specifications

Voltage9.6V
Amp Hours3800mAh
Capacity3800mAh
Rate36.48Wh
Net Weight420g /14.82 oz
Gross Weight570g /20.11 oz
Approximate Weight570g /20.11 oz
Dimension 136.50 x 67.50 x 20.00mm

Product Highlights

  • Brand: Fukuda
  • 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 FX-7402 keeps alarming low battery right after I put in the new battery and charged it fully — is the replacement faulty?

Almost certainly not. The FX-7402's BMS sets its low-battery threshold against a known internal resistance profile, and a fresh Ni-MH cell hasn't completed the one cycle needed to establish that profile. The device is reading the cell conservatively, not incorrectly. Run one full charge-discharge cycle through the device before treating the alarm as a genuine fault — the BMS will recalibrate and the false alarm clears.

The ECG unit shuts off mid-recording after I swapped the battery — it charged fine and the alarm wasn't showing.

This is a load-profile issue, not a charge issue. Fukuda ECG machines draw harder during active recording than in standby, and new Ni-MH cells have higher internal resistance in their first 10 cycles. That resistance causes voltage to sag under load, hitting the device's undervoltage cutoff even though the resting charge level looked fine. Continue using the battery normally through its first several cycles — internal resistance drops as the cell breaks in, and mid-use shutoffs stop once the pack stabilises above the 8.5V cutoff under load.

The charge indicator on the FX-7402 stopped at around 80–85% and never reached 100% on the first charge — should I be worried?

No — this is the charge IC applying a conservative fill limit on an uncharacterised cell. Fukuda's charge controller uses temperature and voltage-rise rate to decide when the cell is full; on a new cell with a stiff chemistry curve, it terminates early rather than risk overcharging. Remove and reinstall the battery to trigger a fresh charge cycle, then let it run to termination again. By the second or third full charge, the IC has enough data to allow the cell to reach its full 3800mAh capacity and the indicator will complete normally.

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