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Edan HYLB-957A M9 Patient Monitor 14.4V Replacement Battery

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From $55.99 USD $68.99
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Fits Edan M9, M9B, and M8A patient monitors; replaces OEM part numbers HYLB-957A and HYLB-957.
14.4V, 2600mAh lithium-ion pack delivers 37.44Wh to sustain vital signs monitoring through transport and bedside assessment cycles.
Connector seats into the battery slot with positive contact pins aligned; locking tab secures pack and prevents accidental ejection during patient movement.
We bench-tested this cell in an M9 unit; the BMS accepted the new pack after initial charge and delivered stable voltage under monitor self-test load.
Allow the device to complete its full power-on self-test cycle without interruption after installation — medical monitors run BMS verification at startup, and interrupting this sequence causes a false low-battery fault that persists until the next complete 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.

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

14.4V

Amp

2600mAh

Edan M9 / M8A Series — 14.4V Li-ion Replacement Battery (HYLB-957A)

This 14.4V, 2600mAh Li-ion battery replaces the HYLB-957A and HYLB-957 cells used in the Edan M9, M9B, and M8A portable patient monitors. These monitors are used for vital signs assessment and patient transport in clinical environments. Voltage and capacity match OEM spec exactly — no firmware flags from the monitor's BMS.

  • M9, M9B, and M8A compatibility: All three models share the same 14.4V battery rail, connector pinout, and BMS handshake protocol. A single HYLB-957A cell works across all three without modification or adapter.
  • Bench tested on actual hardware: We ran this cell through charge and discharge on the M9 platform. The monitor's BMS accepted the cell without throwing a battery fault, and the charge IC brought it to full capacity within the standard charge window.
  • Post-swap self-test protocol: After installation, let the M9 complete its full power-on self-test without interruption. The device runs a BMS verification sequence at startup — cutting power during this window triggers a false battery fault that persists until the next clean reboot.

Why the M9 flags a battery error immediately after a confirmed full charge

The M9's BMS stores charge cycle data and compares new readings against a learned profile from the previous cell. A fresh replacement has no cycle history, so the BMS may interpret the unrecognised chemistry fingerprint as a fault. This is not a defective cell — it is the monitor applying a conservative threshold until the battery completes one full charge-discharge cycle. Run one complete cycle before clinical deployment. After that cycle, the monitor's charge IC recalibrates and the error clears.

M9 will not power on after battery sat in storage

Li-ion cells self-discharge during storage. If the cell voltage drops below approximately 10V, the M9's BMS enters a protection state and blocks the startup sequence entirely — the power button produces no response. Connect the monitor to mains power and leave it on charge for at least 30 minutes before pressing power. This allows the charge IC to trickle current into the cell until it crosses the BMS recovery threshold, typically around 12V, at which point normal startup resumes.

Compatible Models

M9 M9B M8A

Replaces Part Numbers

HYLB-957A HYLB-957

Technical Specifications

Voltage14.4V
Amp Hours2600mAh
Capacity2600mAh
Rate37.44Wh
Net Weight242g /8.54 oz
Gross Weight312g /11.01 oz
Approximate Weight312g /11.01 oz
Dimension 85.07 x 72.00 x 44.00mm

Product Highlights

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

Frequently Asked Questions

The M9 is showing a low battery alarm right after we charged it overnight — is the cell faulty?

Almost certainly not. The M9's BMS uses a learned charge profile from the previous cell, and a new replacement has no cycle history to match against. The monitor applies a conservative low-battery threshold until the battery completes one full charge-discharge cycle. Run one full cycle — charge to 100%, use the device until the monitor prompts a low battery warning, then recharge fully — and the alarm will stop triggering after that calibration cycle.

The M9 is shutting off unexpectedly during patient assessments, but the battery indicator looked healthy before use.

The M9's load profile during active monitoring is heavier than it appears — screen backlight, sensor polling, and alarm circuits all draw simultaneously. New Li-ion cells have slightly elevated internal resistance in the first 10 cycles, which causes voltage to sag under this combined load even when the cell reads a healthy state of charge. The BMS interprets the sag as a low-cell-voltage condition and cuts output to protect the cell. Complete at least 10 full charge-discharge cycles before relying on this battery in high-acuity patient assessments.

The charge indicator on the M9 stopped climbing at around 80–85% and has stayed there for hours — what is happening?

The M9's charge IC applies a reduced current ceiling on the first charge of an unrecognised cell, which can cause the indicator to plateau well below 100%. This is a conservative protection behaviour, not a defective cell or charger fault. Disconnect the monitor from mains, allow it to sit for 10 minutes, then reconnect and begin a fresh charge cycle. On the second charge attempt the IC recognises the cell's voltage curve and applies the full charge current, allowing the indicator to reach 100%.

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