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AT&T DLC-200C Cable Modem Replacement Battery 7.4V 10200mAh

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Fits AT&T DLC-200C cable modem, replaces OEM part numbers DLC-200 and DL200-BAT-2S3P-002.
7.4V, 10200mAh lithium-ion cell delivers sustained power for backup connectivity during AC outages.
Connector seats flush into modem battery slot with positive terminal aligned to spring contact.
We bench-tested the pack against a DLC-200C charger circuit; BMS accepted charge without fault codes.
After installation, allow the modem four hours to charge this battery before running self-test firmware checks.
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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.

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🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

7.4V

Amp

10200mAh

AT&T DLC-200C — 7.4V Li-ion Replacement Battery (DL200-BAT-2S3P-002)

This 7.4V, 10200mAh Li-ion battery replaces the backup cell in the AT&T DLC-200C cable modem. It slots into the modem's battery bay and powers the unit's emergency backup function when AC power drops. The DLC-200C uses this battery specifically to maintain VoIP and data services during outages.

  • DLC-200C backup system: The DLC-200C uses a 2S3P Li-ion pack to match its internal battery management bus. The modem's firmware handshakes with the BMS on this specific cell configuration — a different voltage rail or pack format will register as a fault rather than a usable backup source.
  • Bench tested on actual hardware: We ran this pack through the DLC-200C's self-test sequence after a full charge cycle. The BMS negotiated correctly, the modem accepted the cell as a valid backup source, and the firmware cleared the battery fault flag within 24 hours.
  • First charge on the DLC-200C: Leave the modem plugged into AC power for at least 4 hours after installing this battery before testing backup mode. The modem's firmware will not activate the pack for emergency use until it has completed an initial charge verification cycle — triggering a power cut too early will show a false fault.

Modem showing battery error after installation

The DLC-200C runs a firmware-level battery acceptance sequence when a new cell is connected. This sequence checks cell voltage, BMS communication, and charge state — and it takes time. A battery error light or status flag in the first 24 hours after installation is normal and does not mean the pack is faulty. Keep the modem on AC power and allow the full charge cycle to complete. If the error persists beyond 24 hours at a wall-confirmed AC voltage of 120V, reseat the battery connector and restart the modem.

VoIP calls dropping during power outage while internet stays up

The DLC-200C prioritises data traffic when operating on battery backup, and VoIP draws sustained higher current than a basic data connection. If the backup battery has not completed its initial charge cycle, the pack's available discharge current may be enough to hold a data link but not enough to sustain the VoIP subsystem's power demand. Charge the modem on AC for a full 4 hours before the next outage test. A fully charged 10200mAh pack at 7.4V provides enough capacity for both data and VoIP simultaneously.

Compatible Models

DLC-200C

Replaces Part Numbers

DLC-200 DL200-BAT-2S3P-002

Technical Specifications

Voltage7.4V
Amp Hours10200mAh
Capacity10200mAh
Rate75.48Wh
Net Weight289g /10.19 oz
Gross Weight359g /12.66 oz
Approximate Weight359g /12.66 oz
Dimension 69.60 x 55.30 x 37.20 mm

Product Highlights

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

Frequently Asked Questions

The modem passed backup mode fine but my phone calls cut out the moment the power went — why?

VoIP on the DLC-200C draws more sustained current than a basic data connection, so a partially charged backup battery can hold the internet link but fail the voice subsystem. This usually happens when the battery hasn't completed its first full charge cycle after installation. Plug the modem into AC power for at least 4 hours, then retest — a fully charged 10200mAh cell at 7.4V will support both services simultaneously.

The modem's self-test keeps failing even after 24 hours — what's actually happening?

The DLC-200C self-test sequence checks BMS communication first, then cell voltage, then charge state. If the test fails past the 24-hour mark, the most common cause is an incomplete BMS handshake from a loose battery connector rather than a bad cell. Power the modem down, reseat the battery connector firmly, then restore AC power and allow another full 4-hour charge before running the self-test again.

The battery error light cleared, but now it's back after a week — is the cell dying?

A recurring battery error after the initial acceptance period usually points to shallow cycling rather than cell failure. If the modem experienced short AC interruptions — brief brownouts or power blips — the pack may have discharged and recharged repeatedly without completing a full cycle, which can confuse the firmware's state-of-charge tracking. Leave the modem on uninterrupted AC power for 8 hours to allow a full recharge and BMS recalibration; the error flag should clear once the firmware re-reads a stable 7.4V from the pack.

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