Cisco DPQ3925 10.8V Replacement Battery PB013 3400mAh
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Cisco DPQ3925 10.8V Replacement Battery PB013 3400mAh - is backordered and will ship as soon as it is back in stock.
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Battery Care Tips
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
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
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🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.
Cisco DPQ3925 10.8V Replacement Battery PB013 3400mAh - is backordered and will ship as soon as it is back in stock.
Voltage
10.8V
Amp
3400mAh
Cisco DPQ3925 / DPQ3212 — 10.8V Li-ion Replacement Battery (PB013)
This 10.8V, 3400mAh Li-ion battery replaces the internal backup cell in the Cisco DPQ3925 and DPQ3212 DOCSIS 3.0 cable modems. These modems use a battery backup unit to sustain internet and VoIP service during a mains power outage. OEM part numbers covered: PB013, 4033435, SMPCM1, FLK644A.
- DPQ3925 and DPQ3212 compatibility: Both models share the same 10.8V three-cell battery bay, identical connector pinout, and the same BMS handshake protocol with the modem's firmware. One cell fits both units without modification.
- Bench tested on actual hardware: We ran this cell through full charge cycles on the DPQ3925 platform. The modem's BMS accepted the cell without fault codes after a complete charge cycle, and the battery status LED cleared to solid green.
- First-charge sequence after installation: After fitting the battery, leave the modem plugged into mains power for a full four hours before testing backup function. The modem firmware will not commit the battery to emergency duty until it completes an internal charge-and-verify cycle. Testing before that window will trigger a false self-test failure.
Why the DPQ3925 battery self-test fails after a swap
The DPQ3925 runs an automated self-test roughly 90 seconds after it detects a new battery. If the cell voltage is below the firmware's acceptance threshold — typically around 10.0V — the test trips and logs a fault. A battery shipped in storage-state charge will almost always be below that mark. Plug the modem into mains, allow four hours of charge, then press and hold the battery test button to re-run the check. The test passes once the cell reaches full charge and the BMS confirms cell balance across all three series groups.
Internet stays up during an outage but VoIP calls drop immediately
Data and VoIP draw very different current levels. The DPQ3925's VoIP subsystem requires sustained power headroom that the battery only provides once it is fully charged — a partially charged cell can sustain the lower-draw data circuits but sags under the VoIP amplifier load. If calls drop within seconds of a power cut but the internet link holds, the battery has not completed its charge cycle. Return the modem to mains power, charge for a full four hours, and verify the battery LED shows solid green before testing again.
Compatible Models
Replaces Part Numbers
Technical Specifications
Product Highlights
- Brand: Cisco
- 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 DPQ3925 battery light is flashing amber after I installed the new battery — is it faulty?
A flashing amber LED on the DPQ3925 means the modem's firmware has detected the new cell but has not yet accepted it into active standby. This is normal for up to 24 hours after installation. Leave the modem on mains power and do not run the self-test during this window. Once the cell reaches full charge and the BMS clears, the LED will switch to solid green.
The modem ran a self-test and reported "Battery Failed" 10 minutes after I put the new battery in — what went wrong?
The DPQ3925 triggers its automatic self-test too early for a freshly installed cell. A battery in storage-state charge typically sits below 10.0V, which is under the firmware's pass threshold. The self-test result is not a verdict on the cell — it is a charge-state snapshot taken at the wrong moment. Charge the modem on mains for four hours, then press and hold the battery test button to force a fresh test cycle.
During a power cut, my internet came back on battery but my phone line went dead — why do they behave differently?
The DPQ3925 prioritises the DOCSIS data path because it draws less current; the VoIP amplifier stage requires sustained higher current that a partially charged or degraded cell cannot hold under load. If the phone line drops immediately but broadband stays up, the battery's state of charge is too low to meet the VoIP power budget. Restore mains power, charge for a full four hours until the LED goes solid green, then verify the battery reads at or above 12.0V with a multimeter on the connector terminals before relying on it for voice calls.
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