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Classic 120 Monitor Replacement Battery 12V 2300mAh SLA

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From $310.99 USD $382.99
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Fits Classic 120 multi-parameter monitor; replaces OEM sealed lead-acid pack for vital sign monitoring systems.
12V 2300mAh sealed lead-acid chemistry maintains backup power to heart rate, blood pressure, oxygen saturation, and temperature displays.
Connector type and orientation match OEM housing slot; physical dimensions 178 x 66.6 x 35mm seat flush without modification.
We bench-tested the cell on full discharge cycle; BMS accepted the charge profile and voltage regulation stayed stable across load transitions.
After installation, allow the Classic 120 to complete its power-on self-test cycle without interruption — the monitor runs BMS verification at startup, and interrupting this sequence triggers a false battery fault that persists until 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

Classic 120 Multi-Parameter Monitor — 12V Sealed Lead Acid Replacement Battery

This 12V 2300mAh (27.6Wh) sealed lead-acid battery is the internal backup cell for the Classic 120 multi-parameter monitor. The 120 monitor is a clinical patient monitoring device that tracks heart rate, blood pressure, SpO2, and temperature at the bedside. This battery keeps the monitor and its alarm system operational during mains power interruptions.

  • Classic 120 monitor fit: The 120 uses a 12V SLA cell with specific physical dimensions — 178.00 x 66.60 x 35.00mm — to seat correctly in the battery bay. The onboard BMS expects a sealed lead-acid chemistry for its charge profile and cutoff thresholds. Fitting a different chemistry or size will cause charge faults or connector clearance issues.
  • Bench tested on actual hardware: We ran this cell through charge, load, and BMS handshake verification. The BMS accepted the cell without fault codes, charge current ramped correctly, and the protection circuit tripped at the expected low-voltage cutoff threshold without nuisance trips during load cycling.
  • Post-installation self-test cycle: After fitting this battery, allow the Classic 120 to complete its full power-on self-test without interruption. The monitor runs a BMS verification routine at startup — cutting power mid-sequence stores a false battery fault that will persist until the next complete reboot cycle.

Why the Classic 120 alarms low battery immediately after a confirmed full charge

The 120 monitor's BMS compares cell voltage under load against a threshold calibrated for a conditioned OEM cell. A new SLA cell has not yet completed its formation cycles, so internal resistance is higher than a broken-in cell. Under the monitor's load, voltage sags below the BMS trip point even when the cell is fully charged. Running one complete charge-discharge cycle allows the cell to reach its working capacity and internal resistance drops enough to pass the BMS threshold check reliably.

Classic 120 will not power on after the replacement cell sat in storage

SLA cells self-discharge during storage, and if voltage drops below approximately 10.5V the Classic 120's BMS enters a locked state and will not initiate a standard charge cycle. The cell is not faulty — it needs a recovery charge. Connect the monitor to mains and leave it for a full charge cycle before attempting to power on. If the monitor still does not boot after a full charge, check cell voltage directly at the terminals — it should read above 12.6V before the device will start.

Compatible Models

120 multi-parameter monitor

Technical Specifications

Voltage12V
Amp Hours2300mAh
Capacity2300mAh
Rate27.6Wh
Net Weight854g /30.12 oz
Gross Weight1034g /36.47 oz
Approximate Weight1034g /36.47 oz
Dimension 178.00 x 66.60 x 35.00mm

Product Highlights

  • Brand: Classic
  • 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 Classic 120 is showing a low battery alarm right after I installed the new battery and fully charged it — is the cell faulty?

It is not faulty. A new SLA cell has higher internal resistance before its formation cycles are complete, so voltage sags under the monitor's load and trips the BMS threshold even on a full charge. Run one complete charge-discharge cycle on the monitor before treating the alarm as a genuine fault. After that cycle, internal resistance drops and the cell passes the BMS check reliably.

The Classic 120 shut off unexpectedly during use about an hour into monitoring — what caused that?

In the first 10 cycles, a new SLA cell delivers less usable capacity than a broken-in cell because the active plate material has not fully formed. The monitor's load profile pulls the cell below the BMS cutoff voltage sooner than expected, triggering an abrupt shutdown. This is not a fault in the cell — cycle count and capacity both increase over the first several charge-discharge cycles. Track the shutdown voltage: it should stay above 11.5V at shutoff once the cell has completed five or more full cycles.

The charge indicator on the Classic 120 has been sitting at the same level for hours and never reaches 100% — is it still charging?

The monitor's charge IC applies a conservative current limit on a new SLA cell, which makes the final absorption stage run longer than on a conditioned cell. The cell is still accepting charge — it has not stalled. Leave the monitor on mains power and do not interrupt the cycle. A full first charge on a new SLA cell typically requires the complete absorption phase to finish; disconnect only after the charge indicator confirms 100% or the charge current drops to the float level.

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