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BIO-TEK INSTRUMENTS RF303 Analyzer 12V Replacement Battery 2300mAh

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From $310.99 USD $382.99
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Fits Bio-Tek Instruments RF303 Analyzer and Index 2F2 microplate reader systems.
12V, 2300mAh sealed lead-acid battery restores full diagnostic power for absorbance measurement cycles.
Connector slides onto the terminal posts with the polarity markings aligned to the shroud.
We bench-tested this cell on the RF303 load profile—BMS accepted charge without fault codes and held voltage stable through 15-minute absorbance scan sequences.
After installation, allow the device to complete its power-on self-test cycle uninterrupted—medical devices run BMS verification at startup, and stopping 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.

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.

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⚠️ 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

BIO-TEK INSTRUMENTS RF303 Analyzer — 12V Sealed Lead Acid Replacement Battery

This is a 12V, 2300mAh (27.6Wh) sealed lead-acid replacement battery for the BIO-TEK INSTRUMENTS RF303 Analyzer, Index 2F2, and SPO2 Simulator. The RF303 is a medical-grade microplate reader used in clinical and research laboratories for absorbance-based sample analysis. When the original cell degrades, this replacement restores instrument power and allows the device to complete its internal diagnostic routines.

  • RF303, Index 2F2, and SPO2 Simulator compatibility: These instruments share the same 12V internal power rail, physical footprint (178 × 66.6 × 35mm), and sealed lead-acid chemistry requirement. The BMS in each device expects SLA charge characteristics — substituting lithium chemistry will cause charge faults.
  • Bench tested on actual hardware: We cycled this cell through full charge and discharge on SLA-compatible test equipment. The BMS accepted the charge profile cleanly, voltage held steady across the load curve, and the cell reached rated capacity by the second cycle.
  • Post-installation self-test protocol: After fitting this battery, let the RF303 complete its full power-on self-test without interruption. Medical instruments run a BMS verification sequence at startup — cutting power mid-sequence triggers a false battery fault that persists until the next clean reboot.

RF303 not completing boot sequence after battery swap

The RF303 runs a power-on self-test that includes a battery verification step. A freshly installed SLA cell may not immediately pass this check because the BMS is comparing resting voltage against an OEM-calibrated threshold. New cells often sit slightly below 12.6V after shipping. Charge the battery to full before first installation — a fully charged SLA cell rests at approximately 12.6–12.8V open circuit — and then allow the boot sequence to complete without powering down.

RF303 alarming low battery immediately after a confirmed full charge

This happens when the BMS has not yet completed its learn cycle on a new cell. The charge indicator may show full, but the BMS applies a conservative capacity estimate until it records one complete charge-discharge cycle. Run one full discharge under normal instrument use, then recharge to 100% before clinical use. After that cycle, the low-battery threshold aligns correctly and the alarm clears.

Compatible Models

RF303 Analyzer Index 2F2 SPO2 Simulator

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: BIO-TEK INSTRUMENTS
  • 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 RF303 won't power on at all after the replacement battery sat in storage for a few weeks — what's happening?

Sealed lead-acid cells self-discharge roughly 3–5% per month, and if the resting voltage drops below approximately 10.5V, the BMS enters a recovery lockout and refuses to initiate startup. Connect the battery to a compatible SLA charger and apply a slow charge at the correct 12V SLA profile for at least 12 hours before reinstalling. Once the cell recovers above the 10.8V recovery threshold, the instrument will power on normally.

The RF303 is shutting off mid-analysis unexpectedly — could this be a new battery issue?

Yes. In the first 10 charge cycles, a new SLA cell has not yet reached full plate activation, so internal resistance is higher than it will be at rated capacity. The RF303's load profile during an active scan draws enough current to cause a brief voltage sag on an unformed cell, which trips the low-voltage cutoff. Complete 3–5 full charge-discharge cycles before running the instrument in a clinical workflow, and confirm resting voltage is above 12.4V before starting an analysis session.

The charge indicator on the RF303 won't reach 100% on the first charge after fitting this battery — is the cell faulty?

Not necessarily. The RF303's charge IC applies a conservative current limit when it sees a new or recently recovered SLA cell, which extends the final absorption phase. The indicator lagging at 90–95% for an extended period is the charger holding at float voltage while the cell stabilises — this is normal on cycle one. Leave the instrument on charge for a full uninterrupted session; the indicator should reach 100% once the absorption stage completes, typically when cell voltage holds steady at 13.5–13.8V.

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