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Cedar CT8 Diagnostic Scanner Replacement Battery 3.8V 7500mAh

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From $66.99 USD $82.99
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Fits Cedar CT8 and CT8X2 diagnostic scanners replacing OEM part number 4990112.
3.8V and 7500mAh capacity supports full diagnostic sessions without mid-scan power loss on automotive fault-code readers.
Connector type and orientation match CT8 factory slot exactly with positive-terminal-forward orientation and integral locking tab.
We bench-tested this cell in the CT8 platform — BMS initialized on first charge cycle with no voltage cutoff errors or communication faults.
Export all saved vehicle profiles to the scanner's cloud storage or USB before removing the battery — CT8 diagnostic data lives in RAM powered by this cell only.
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

3.8V

Amp

7500mAh

Cedar CT8 / CT8X2 — 3.8V Li-Polymer Replacement Battery (4990112)

This is a 3.8V, 7500mAh lithium-polymer battery for the Cedar CT8 and CT8X2 automotive diagnostic scanners. It replaces OEM part number 4990112. Fits technicians running full-day shop sessions where the original cell no longer holds a working charge.

  • CT8 and CT8X2 compatibility: Both models use the same 4990112 cell, share the same 3.8V power rail, and use the same connector and BMS handshake. One battery covers both.
  • Bench tested on actual hardware: We cycled this cell through charge and discharge on the CT8 platform. The BMS accepted the cell without fault codes, held voltage across OBD communication sessions, and did not trigger low-voltage cutoff during live data streaming.
  • Export vehicle profiles before swapping: The CT8 stores saved vehicle profiles and fault code history in RAM backed by the main battery. Pull those records to USB or the Cedar app before you remove the old cell — they will not survive a full power loss.

Why the CT8 BMS rejects a new cell on first boot

A freshly shipped lithium-polymer cell typically arrives at 30–50% state of charge. The CT8 BMS checks cell voltage at power-on and will refuse to boot if it reads below the minimum threshold — usually around 3.2V per cell. This is not a faulty battery. Plug the scanner in before attempting to power it on and let it charge to at least 3.6V. Once the BMS sees voltage above threshold, it will initialise and the unit will boot normally.

Wireless link dropping mid-diagnostic session

BLE and Wi-Fi modules on the CT8 draw a short current spike when polling vehicle ECUs. When the battery is degraded, voltage sags briefly under that load and the wireless stack loses its connection. The scanner may show a timeout error or simply freeze mid-read. This symptom appears before the battery indicator shows critical — the display driver voltage holds up longer than the RF circuitry. A fresh cell at full charge eliminates the sag and keeps the link stable through full OBD sessions.

Compatible Models

CT8 CT8X2

Replaces Part Numbers

4990112

Technical Specifications

Voltage3.8V
Amp Hours7500mAh
Capacity7500mAh
Rate28.5Wh
Net Weight127g /4.48 oz
Gross Weight177g /6.24 oz
Approximate Weight177g /6.24 oz
Dimension 118.00 x 93.80 x 5.60mm

Product Highlights

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

Frequently Asked Questions

My CT8 won't turn on after I put the new battery in — did I get a dead cell?

Almost certainly not. Li-polymer cells ship at partial charge, and the CT8 BMS will not boot if it reads below roughly 3.2V. Connect the scanner to a charger for at least 20–30 minutes before pressing the power button. If the charge LED comes on, the cell is good — the BMS just needed voltage above its boot threshold before it would initialise.

All my saved vehicle profiles disappeared after I swapped the battery — where did they go?

The CT8 keeps vehicle profiles and stored fault code history in RAM that is powered by the main battery. When that battery goes to zero — which happens during a swap — that memory is wiped. Before removing the old cell, export your data to USB or sync to the Cedar app. There is no way to recover profiles after the power has been lost.

My CT8 keeps losing the wireless connection mid-scan even with a new battery installed — what's wrong?

Check that the replacement cell charged fully before use — a partial charge can cause voltage sag under the current spikes the BLE or Wi-Fi module draws during ECU polling. If the issue persists at full charge, check the battery contacts in the housing for oxidation or debris, which creates resistance and amplifies sag. Clean the contacts with isopropyl alcohol, reseat the battery, and charge to 4.2V before retesting.

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