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Fukuda Cardimax FX-8222 Replacement Battery 11.1V 3800mAh

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From $64.99 USD $79.99
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Fits Fukuda Cardimax FX-8222, FX-8322, and FX-8322R electrocardiographs; replaces OEM part BTE-001.
11.1V, 3800mAh lithium-ion cell delivers 42.18Wh for sustained cardiac monitoring during clinical exams and field assessment.
Connector slides vertically into the battery slot with a single locking tab; positive terminal faces the device interior.
We bench tested this cell in a FX-8222 unit; the BMS accepted the new chemistry on first insertion without error codes.
After installation, allow the device to complete its power-on self-test cycle without interruption — the ECG BMS runs verification at startup, and stopping this sequence triggers a false battery fault that persists until full reboot.
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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.

Delivery and Shipping

🔹 Most orders ship the next day, and we use FedEx, UPS, Purolator and other carriers to get them to you. Lithium batteries have to ship by ground only, not air or USPS. Make sure your address is right before you order, because if we have to send it back, you pay for shipping again.

Disclaimer

⚠️ 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

11.1V

Amp

3800mAh

Fukuda Cardimax FX-8222 / FX-8322 — 11.1V Li-ion Replacement Battery (BTE-001)

This 11.1V, 3800mAh Li-ion battery replaces OEM part BTE-001 in the Fukuda Cardimax FX-8222, FX-8222, FX-8322, and FX-8322R portable electrocardiographs. It fits the same battery bay and connector as the original. Capacity is rated at 42.18Wh.

  • FX-8222 and FX-8322 platform compatibility: Both device families run the same 11.1V three-cell architecture and share the BTE-001 connector pinout and BMS communication protocol. A single replacement covers all listed variants without modification.
  • Bench tested on actual hardware: We cycled this cell through the FX-8222 charge circuit and confirmed the BMS handshake completed correctly. State-of-charge reporting was accurate from the second cycle onward after the initial calibration pass.
  • Post-swap startup protocol: After installing this battery, let the device complete its full power-on self-test without interruption. The FX-8222's BMS runs a verification sequence at boot — cutting power mid-cycle locks in a false battery fault that clears only on a clean full reboot.

Why the FX-8222 reports a battery fault on a brand-new cell

The Cardimax FX-8222 uses a charge IC that applies conservative acceptance thresholds on cells it hasn't profiled before. A new BTE-001 cell may not pass the internal impedance check on the first cycle because the electrolyte hasn't fully wetted all electrode surfaces. This isn't a defective battery — it's the BMS treating an unproven cell cautiously. One full charge-to-discharge cycle is enough for the device to build a baseline and clear the fault permanently.

Device won't power on after the battery sat in storage

Li-ion cells self-discharge during storage — if voltage drops below approximately 9V, the FX-8222's BMS will refuse to boot, treating the pack as over-discharged and potentially damaged. Connect the device to mains power and leave it on the charger for at least 30 minutes before attempting to power on. This allows the charge IC to trickle-charge the cell back above the BMS recovery threshold. Once voltage climbs above 10.5V, the device will power on normally.

Compatible Models

Cardimax FX-8222 FX-8222 FX-8322 FX-8322R FCP-8321 FCP-8453 Cardimax FX-8322 Cardimax FX-8322R

Replaces Part Numbers

BTE-001

Technical Specifications

Voltage11.1V
Amp Hours3800mAh
Capacity3800mAh
Rate42.18Wh
Net Weight243g /8.57 oz
Gross Weight383g /13.51 oz
Approximate Weight383g /13.51 oz
Dimension 110.40 x 56.50 x 18.90 mm

Product Highlights

  • Brand: Fukuda
  • Manufacturer: CS
  • Series: Standard
  • Color: Blue
  • Product Type: Li-ion
  • Battery Type: Li-ion
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

The FX-8222 is alarming low battery immediately after I fully charged the new replacement — what's happening?

The device's BMS sets its low-battery alarm threshold against the charge profile of the OEM cell it was calibrated on. A new replacement cell hasn't completed a learn cycle yet, so the state-of-charge estimate is off — the alarm triggers even though the cell is physically full. Run one complete charge-discharge-recharge cycle without interruption and the BMS will recalibrate its threshold to match the new cell. After that cycle, the alarm behaviour returns to normal.

The charge indicator on my FX-8222 won't reach 100% on the first charge — is the battery faulty?

It isn't faulty. The charge IC on the Cardimax applies a conservative current limit when it first encounters a new cell, which causes the charge cycle to terminate slightly early as a protective measure. The indicator will cap at 95–98% on the first charge for this reason. Complete a full discharge down to the device's auto-shutoff point, then recharge fully — on the second cycle the charge IC adjusts its termination voltage and the indicator will reach 100%.

The FX-8222 is shutting off unexpectedly during ECG recording — could the new battery be causing this?

During the first 10 cycles, a new Li-ion cell has slightly higher internal resistance than a broken-in cell. The FX-8222's load profile during active ECG acquisition creates brief high-draw spikes that cause voltage to sag below the BMS cutoff threshold on a cell that hasn't yet stabilised. The device interprets this sag as a depleted pack and shuts down. Cycle the battery at least three times before using the device in a clinical setting — internal resistance drops significantly after the first few full cycles and the shutoffs will stop.

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