About this replacement
ARRIS TM602G/115 Series — 7.4V Li-ion Replacement Battery (BPB022S)
This is a 7.4V, 2600mAh Li-ion battery for the ARRIS TM602G/115 cable modem and related models including the TM02AC1G6, TG862G, and TG852G. It slots into the modem's backup bay and provides power during outages so VoIP calls and internet access stay up. The battery also cross-references OEM part numbers BPB026S, BPB024, BPB024H, 49100160JAP, and ARCT00777M.
- Multi-model compatibility: These ARRIS modems share the same 7.4V backup battery architecture, connector pinout, and BMS handshake protocol — so one cell works across the TM and TG series listed above without modification.
- Bench tested on actual hardware: We ran this battery through a full charge cycle on an ARRIS TG862G and confirmed the BMS accepted the cell, cleared fault flags, and held voltage within the modem's expected 7.2–7.5V operating window under simulated outage load.
- First-charge protocol for cable modem backup cells: After installing, leave the modem powered on and connected for at least 4 hours before triggering any backup test. The modem's firmware runs a charge-acceptance sequence before it registers the battery as ready — skipping this step causes false battery error codes.
Why VoIP calls drop during a power outage even with a new battery installed
VoIP requires higher sustained current than the data connection. If the battery hasn't completed its initial charge-acceptance cycle, the modem firmware won't route power through the backup cell when mains power drops. The modem may stay online for basic data but cuts VoIP because that subsystem draws more current and the firmware treats the battery as unverified. Install the battery, leave the modem on mains power for 4 hours, and then confirm the battery LED shows solid green before testing outage performance.
Modem showing a battery error light after swapping the cell
A battery error indicator immediately after installation is normal and does not mean the battery is faulty. ARRIS modem firmware runs a timed charge-verification routine — it won't clear the error until the new cell has charged and passed an internal self-test. This process takes up to 24 hours on some firmware versions. If the error light is still on after 24 hours of continuous mains power, check that the battery connector is fully seated and confirm voltage at the terminals reads 7.2V or above.