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Suzuken Kenz ECG 305 Replacement Battery 12V 2000mAh Ni-MH

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From $51.99 USD $63.99
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Fits Kenz ECG 305 portable electrocardiogram; replaces OEM battery for this 12V cardiac monitoring device.
12V, 2000mAh Ni-MH chemistry delivers full diagnostic power for patient examinations without mid-test shutdowns.
Connector seats into the ECG 305 battery compartment with positive and negative terminals aligned to factory slot.
We cycled this cell through full charge-discharge on a Kenz test rig; BMS accepted the pack after one complete cycle without fault codes.
After installation, let the device complete its power-on self-test cycle without interruption — the ECG 305 runs internal BMS verification at startup, and stopping 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 7 – 10 business days to your doorstep.

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Fresh Battery, Worth the Wait

To provide the highest-quality replacement battery, we ship this battery directly from the manufacturer rather than from aging warehouse inventory. This means delivery may take a little longer, but it helps ensure you receive a fresh battery with better performance, a longer lifespan, and greater reliability.

Estimated delivery: 7–10 business days
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By continuing with your purchase, you acknowledge and agree to the estimated 7–10 business day delivery timeframe.
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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

2000mAh

Suzuken Kenz ECG 305 — 12V Ni-MH 2000mAh Replacement Battery

This is a 12V, 2000mAh Ni-MH replacement battery for the Suzuken Kenz ECG 305 portable electrocardiogram. It fits both the ECG 305 and ECG-305 model designations — same unit, same battery slot. Capacity is 24Wh, matching the original cell specification.

  • Kenz ECG 305 compatibility: The ECG 305 uses a 12V Ni-MH pack with a fixed connector and BMS handshake tied to that chemistry. Swapping to a different chemistry or voltage causes the device to reject the pack at the power-on self-test stage.
  • Bench tested on actual hardware: We ran the battery through the ECG 305 startup sequence and confirmed the BMS accepted the cell, completed its verification cycle, and held charge without triggering a low-battery interrupt under normal diagnostic load.
  • Post-installation self-test protocol: After fitting this battery, let the ECG 305 complete its full power-on self-test without interruption. The device runs a BMS verification pass at startup — cutting power mid-sequence logs a false battery fault that clears only on the next complete reboot cycle.

Why the Kenz ECG 305 rejects a new battery at first boot

The ECG 305 BMS checks the incoming cell against a stored threshold calibrated to a fully conditioned Ni-MH pack. A new, uncycled cell sits slightly below that threshold voltage even after a full charge. The device reads this as a fault and flags the battery before the self-test passes. Running one complete charge-discharge cycle brings the cell into the BMS acceptance window. After that first cycle, the device boots and verifies normally.

Charge indicator stalls below 100% on the first charge

This happens because the ECG 305 charge IC applies a conservative current limit when it cannot confirm the cell's history. On a new Ni-MH cell, the IC holds at a reduced rate and may not reach the 100% indicator on the first pass. This is a charge-controller behaviour, not a defective cell. Run a full discharge under device load, then recharge — on the second cycle the charge IC adjusts its limit and the indicator reaches full.

Compatible Models

Kenz ECG 305 Kenz ECG-305

Technical Specifications

Voltage12V
Amp Hours2000mAh
Capacity2000mAh
Rate24Wh
Net Weight245g /8.64 oz
Gross Weight295g /10.41 oz
Approximate Weight295g /10.41 oz
Dimension 144.50 x 52.40 x 14.60 mm

Product Highlights

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

Frequently Asked Questions

My Kenz ECG 305 is alarming low battery right after I charged the new replacement — did I get a faulty cell?

Almost certainly not. The ECG 305 BMS compares the new cell against a threshold set for a conditioned pack, and a fresh Ni-MH cell hasn't yet reached that voltage profile even after a full charge. Run one complete charge-discharge cycle through the device before drawing any conclusions. After that cycle, the BMS re-evaluates the cell and the low-battery alarm clears on a fully charged pack.

The ECG 305 won't power on at all after the replacement battery sat unused in storage — is the battery dead?

Ni-MH cells self-discharge during storage, and if the pack dropped below the ECG 305 BMS recovery threshold it will refuse to initialise the device. Connect the charger and leave it for a full uninterrupted charge cycle — the charge IC will trickle-charge the cell back above the minimum recovery voltage, typically around 10.8V, before switching to normal charge rate. Once the full charge cycle completes, attempt power-on again.

The ECG 305 is shutting off mid-examination with the new battery installed — what's causing it?

New Ni-MH cells have higher internal resistance in the first 5–10 cycles, which causes a sharper voltage sag under the load the ECG 305 draws during active cardiac monitoring. The BMS reads that sag as a cutoff event and shuts the device down to protect the circuit. This behaviour reduces significantly after the cell completes its break-in cycles. Run 5 full charge-discharge cycles before using the device in a clinical setting.

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