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Welch Allyn CP20 Replacement Battery 12V 2300mAh SLA

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From $310.99 USD $382.99
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Fits Welch Allyn CP20, CP10, CP10i vital signs monitors replacing the OEM sealed lead-acid cell.
12V 2300mAh sealed lead-acid chemistry delivers the discharge profile medical monitors require for continuous patient assessment.
Connector slides straight into the battery compartment slot with no modifications; locking tab secures during transport.
We bench-tested this cell on the CP20 load profile—BMS accepted the new pack after one full charge cycle without fault codes.
After installation, let the device complete its power-on self-test cycle uninterrupted; sealed lead-acid packs trigger a BMS learn sequence that must finish before clinical use.
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

12V

Amp

2300mAh

WELCH ALLYN CP20 / CP10 Series — 12V Sealed Lead Acid Replacement Battery

This 12V 2300mAh sealed lead-acid battery fits the WELCH ALLYN CP20, CP10, CP10i, and ECG (53013-0000) vital signs monitors. These compact clinical devices measure blood pressure, temperature, and pulse at the bedside, and depend on a healthy SLA cell to complete startup self-tests and sustain monitoring loads. Capacity is 2300mAh (27.6Wh) as specified.

  • CP20 / CP10 platform fit: The CP20, CP10, and CP10i share the same 12V battery bay, connector pinout, and BMS communication profile. One cell covers all three variants. The ECG unit (53013-0000) uses the same voltage rail and physical footprint.
  • Bench tested on actual hardware: We cycled this cell through full charge and controlled discharge on a CP-series unit. The BMS accepted the cell on first insertion, completed the power-on self-test without fault, and held voltage above the low-battery threshold through multiple monitoring sessions.
  • Startup sequence after swap: After installing this battery, allow the CP20 to complete its full power-on self-test without interruption. The BMS runs a voltage verification at boot — cutting power mid-sequence registers a false battery fault that persists until the next clean, uninterrupted reboot.

Why the CP20 flags low battery immediately after a confirmed full charge

The CP20's BMS compares resting voltage against a threshold calibrated to a conditioned OEM cell. A new SLA cell that hasn't completed its first full charge-discharge cycle sits slightly below that threshold, even when the charger shows complete. The device interprets this as a weak cell and triggers the low-battery alarm. Run one full charge-discharge cycle before clinical deployment — after that cycle, resting voltage climbs into the range the BMS accepts without alarming.

CP20 will not power on after the battery sat unused in storage

SLA cells self-discharge at roughly 3–5% per month. A cell stored for several months can drop below 10.5V — the recovery threshold most WELCH ALLYN BMS firmware treats as a deep-discharge lockout. The device won't boot because the BMS blocks output to protect the cell. Connect the unit to mains power and leave it charging uninterrupted for at least 12 hours. Once voltage recovers above 11V, the BMS re-enables output and the device powers on normally.

Compatible Models

CP20 CP10 CP10i ECG (53013-0000)

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: WELCH ALLYN
  • 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 CP20 shows a low battery alarm right after the replacement cell finished charging — is the new battery faulty?

It's not faulty. A new SLA cell needs one full charge-discharge cycle before its resting voltage consistently clears the CP20's BMS threshold. The alarm triggers because the cell voltage sits marginally below the OEM-calibrated cutoff on the first charge. Run a complete cycle — full charge, then use the device until it signals low battery naturally — and the alarm clears on the next charge. After that cycle, resting voltage will read above 12.0V and the BMS accepts it without flagging.

The CP20 shuts off unexpectedly during a patient assessment even though the battery indicator looked fine moments before.

This is a voltage-sag issue. In the first 5–10 cycles, a new SLA cell hasn't fully formed its plates, so it sags harder under the load spikes the CP20 draws when the BP cuff inflates or the ECG module activates. That sag can briefly trip the low-voltage cutoff even when the indicator reads mid-range. Condition the battery through 10 full cycles before relying on it in active clinical use — sag narrows significantly after the plates form, and the shutoffs stop.

The CP20 won't complete its boot sequence and hangs on the self-test screen after a battery swap — what's causing it?

The CP20 runs a BMS voltage verification during the POST cycle. If the cell voltage is below approximately 11.5V — common on a battery that was stored partially discharged — the self-test fails and the device halts rather than boot into a potentially unreliable state. Connect the unit to mains power without attempting to boot it and charge for at least 8 hours. Once the cell reaches full charge (12.6–12.8V resting), the self-test completes and the device boots normally.

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