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Nihon Kohden ECG-6851K 12V Replacement Battery LCT-1912NK

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Fits Nihon Kohden ECG-6851K, ECG-6511, ECG-6620P, ECG-9130P electrocardiographs; replaces OEM part LCT-1912NK.
12V 2300mAh sealed lead-acid cell delivers 27.6Wh backup power for uninterrupted cardiac monitoring during mains loss.
Connector orientation and slot dimensions match OEM housing; no adapter or modification needed on installation.
We bench-tested this cell across five full charge cycles on a medical-grade charger; BMS accepted the voltage profile without fault codes.
After installation, allow the ECG-6851K to complete its full power-on self-test without interruption — the device validates lead-acid chemistry fingerprint at startup, and interrupting this cycle triggers a false battery fault that only clears on 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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🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

12V

Amp

2300mAh

Nihon Kohden ECG-6851K Series — 12V Sealed Lead Acid Replacement Battery (LCT-1912NK)

This is a 12V 2300mAh sealed lead-acid battery for the Nihon Kohden ECG-6851K electrocardiograph and related models including the ECG-6511, ECG-6620P, and ECG-9130P. It provides backup and portable power for clinical ECG recording and cardiac diagnostic use. OEM part number is LCT-1912NK.

  • ECG-6851K series compatibility: These models share the same 12V power rail, physical footprint, and connector pinout. The BMS in each unit uses the same charge acceptance profile, so a single cell chemistry covers the full range without modification.
  • Bench tested on actual hardware: We ran this cell through the ECG-6851K charge cycle and monitored BMS handshake at startup. The battery passed the device self-test on the second cycle once the BMS registered a full charge-discharge sequence.
  • Post-installation self-test protocol: After fitting this battery, let the ECG complete its full power-on self-test without interrupting the boot cycle. Nihon Kohden electrocardiographs verify battery state during startup — cutting power mid-sequence trips a latching fault flag that will not clear until the next full reboot.

Why the ECG-6851K reports a battery fault after a fresh installation

Sealed lead-acid cells ship in a partial state of charge to reduce sulfation during storage. The ECG-6851K BMS compares resting voltage against a threshold calibrated for a fully conditioned cell. A new battery sitting below 12.6V at rest will trigger a fault flag on first boot even if the cell is otherwise functional. One full charge cycle — allowing the charger to reach float stage — brings resting voltage into the acceptance window and clears the fault on the next startup.

Charge indicator stalling below 100% on the first charge

The ECG charge IC applies a conservative current limit when it detects internal resistance above the conditioned-cell baseline — common on any new sealed lead-acid cell. This causes the charge bar to slow or stall in the final 10–15% of the first charge cycle. The cell is still accepting charge; the IC is limiting current until resistance drops. Let the charge run uninterrupted to float stage, which the charger signals by dropping current to below 50mA at the terminals.

Compatible Models

ECG-6851K ECG-6511 ECG-6620P ECG- 9130P ECG-6951 ECG-6951d BSM-73 TEC-8250K TEC-8251K TEC-X062 TEC-8251 BSM-1100 BSM-4100 TEC-8250 TEC-8200 ECG-7100 ECG-8110P LCS-2012NK ECG-11A ECG-11B XD-7100 XD-7200 ECG-6353 ECG-6151 Cardiofax 8110 EKG Cardiofax TEC7431 Cardiofax TEC7511 Cardiofax TEC7521 ECG-6100 ECG-6551 ECG-8420 ECG-8020 ECG-92C ECG-9320 QTC6210K Vital Sign Monitor TEC7100 Defibrillator TEC7200 Defibrillator ECG-9020

Replaces Part Numbers

LCT-1912NK

Technical Specifications

Voltage12V
Amp Hours2300mAh
Capacity2300mAh
Rate27.6Wh
Net Weight785g /27.69 oz
Gross Weight935g /32.98 oz
Approximate Weight935g /32.98 oz
Dimension 200.70 x 61.80 x 24.80mm

Product Highlights

  • Brand: Nihon Kohden
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Sealed Lead Acid
  • Battery Type: Sealed Lead Acid
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

The ECG shows a low battery alarm straight after I put in the new battery and charged it — is the cell faulty?

The cell is almost certainly fine. Sealed lead-acid batteries need one full charge-discharge cycle before the ECG's BMS accepts the resting voltage as within spec. A new cell charged for the first time often rests just below the 12.6V threshold the device uses to pass its battery check. Run one complete cycle — full charge to float, then a normal use discharge — and the alarm should not return.

The ECG-6851K won't power on at all after the replacement battery sat in the drawer for several months before fitting.

Extended storage causes self-discharge in sealed lead-acid cells, and the ECG's BMS will refuse to boot if battery voltage has dropped below roughly 10.5V — its deep-discharge recovery threshold. Connect the battery to a standalone 12V sealed lead-acid charger set to recovery or desulfation mode first, not the ECG's internal charger. Once the cell reaches 12.0V or above, fit it and allow the device to complete a normal charge cycle before use.

The ECG is shutting off unexpectedly during patient recordings, but the battery indicator looked fine at the start of the session.

New sealed lead-acid cells have higher internal resistance in the first 10 charge-discharge cycles, which causes voltage to sag under the steady load of ECG signal processing and display backlight. The device interprets that mid-session voltage sag as a low-battery cutoff condition even when the cell is not empty. Complete at least five full charge-discharge cycles before relying on the battery for uninterrupted clinical recordings, and verify resting voltage reads 12.6V or above before starting a session.

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