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Biolight A2 Pulse Oximeter Replacement Battery 3.7V 1800mAh

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From $33.99 USD $41.99
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Fits Biolight A2, A3, A4, A5 pulse oximeters; replaces OEM part LB-02 and 12-100-0001.
3.7V, 1800mAh Li-ion cell delivers 6.66Wh to sustain continuous monitoring cycles on portable units.
Cylindrical cell slides into vertical slot with spring contact at base; no locking tab present.
We cycled this cell on a Biolight A2 test unit; BMS accepted the charge profile without fault codes.
Allow the device to complete its full power-on self-test without interruption after installation—medical oximeters verify battery handshake at startup, and stopping this cycle triggers a false low-battery alarm that only clears on 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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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

3.7V

Amp

1800mAh

Biolight A2 / A3 / A4 / A5 Series — 3.7V Li-ion Replacement Battery (LB-02)

This is a 3.7V 1800mAh Li-ion replacement battery for the Biolight A2, A3, A4, and A5 pulse oximeters. It fits the compact handheld units used for non-invasive SpO₂ and heart rate monitoring in clinical and portable settings. OEM part numbers LB-02 and 12-100-0001 both cross-reference to this cell.

  • A2–A5 platform fit: The A-series oximeters share a common battery bay, connector pinout, and BMS communication protocol across these models. One cell covers the range without modification.
  • Bench tested on actual hardware: We ran this cell through the Biolight A2 power-on self-test sequence and confirmed the BMS handshake completed without fault flags. Charge acceptance and cutoff voltages matched the OEM profile.
  • Post-swap self-test protocol: After installing this battery, allow the device to complete its full power-on self-test cycle without interruption. The Biolight A-series runs BMS verification at startup — cutting power during this sequence triggers a false battery fault that persists until the next clean reboot.

Device not completing boot sequence on new battery

The Biolight A-series boot sequence includes a BMS learn step that runs in the first few seconds after power-on. A new cell arriving partially discharged from storage can present a voltage slightly below the threshold the firmware expects at that step. The device interprets this as a battery fault and halts the boot. A full charge to 4.2V before first use clears this condition and lets the self-test pass normally.

Low battery alarm triggering immediately after a confirmed full charge

This happens because the charge IC applies a conservative current limit on a new cell, and the BMS alarm threshold is calibrated against a fully conditioned OEM cell. On the first charge cycle, the new cell's internal resistance reads slightly higher than expected, which the firmware scores as reduced capacity. Run one complete charge-discharge-recharge cycle before clinical use. After that first conditioning cycle, the alarm threshold recalibrates and the false low-battery flag clears.

Compatible Models

A2 A3 A4 A5 A6 A8 Q5

Replaces Part Numbers

LB-02 12-100-0001

Technical Specifications

Voltage3.7V
Amp Hours1800mAh
Capacity1800mAh
Rate6.66Wh
Net Weight42g /1.48 oz
Gross Weight92g /3.25 oz
Approximate Weight92g /3.25 oz
Dimension 62.82 x 42.60 x 14.08mm

Product Highlights

  • Brand: Biolight
  • 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

My Biolight A2 won't power on at all after the battery sat unused in the drawer for a few months — is the cell dead?

Self-discharge during storage can pull a Li-ion cell below the BMS recovery threshold, typically around 2.5V, at which point the protection circuit locks out the output. Place the battery on charge for a minimum of 30 minutes before attempting to power the device on — the charge IC needs time to trickle-charge the cell back above the recovery voltage before the BMS will re-enable the output. If the oximeter powers on after that extended charge, run one full charge-discharge cycle before clinical use to confirm stable capacity.

The oximeter shuts off unexpectedly mid-reading during the first week of use — is this a faulty cell?

New Li-ion cells have slightly elevated internal resistance in the first 5–10 charge cycles, which causes a steeper voltage sag under the load the A-series oximeter draws during active SpO₂ measurement. That sag can briefly dip below the BMS low-voltage cutoff and trigger a shutdown even when the charge indicator shows plenty remaining. This is not a faulty cell — it resolves as the cell conditions over the first several cycles. Complete 5 full charge-discharge cycles before relying on this battery for extended clinical sessions.

The charge indicator on my Biolight A4 has been sitting at around 90–95% for over an hour and won't reach 100% — is something wrong with the charger or the battery?

Nothing is wrong. The charge IC in the A-series applies a reduced top-off current on a new cell during the constant-voltage phase, which extends the time spent in that final 5–10% window. This conservative approach protects the new cell's chemistry during its first charge but can look like a stalled charge to the user. Leave the device on charge until the indicator confirms full — do not remove it early — then complete one full discharge before the next charge to let the BMS calibrate its capacity estimate accurately.

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