Altec Lansing Omni Jacket Replacement Battery 3.7V 10200mAh

Altec Lansing Omni Jacket / iMW678 — 3.7V Li-ion Replacement Battery (INR18650-3S1P)

This is a 3.7V, 10200mAh Li-ion replacement battery for the Altec Lansing Omni Jacket portable Bluetooth speaker, including the iMW678, iMW678-BLK, and iMW678-BLU variants. It restores power to the speaker when the original cell has degraded past usable capacity. Voltage and cell format match the OEM specification exactly.

• iMW678 series fit: All listed iMW678 variants share the same internal cell format, connector pinout, and BMS handshake. The 3S1P configuration — three 18650 cells in series — sets the pack voltage at 3.7V nominal, which the speaker's onboard controller expects for both charging and audio output regulation.
• Bench tested on actual hardware: We cycled this pack through charge, standby, and high-volume audio playback. The BMS held communication with the speaker's fuel gauge circuit throughout, and the protection cutoff triggered correctly at low-cell threshold without nuisance trips during amplifier current spikes.
• Monthly discharge cycle for iMW678 owners: Let the speaker run down below 20% at least once a month before recharging. The iMW678 is typically kept on a desk or shelf and topped off constantly — this shallow-cycle pattern causes fuel gauge drift over time, so the battery indicator reads inaccurate and you lose usable capacity faster than the cells actually degrade.

Bluetooth dropping at high volume on the Omni Jacket

At maximum volume, the amplifier and Bluetooth radio draw current simultaneously, creating combined spikes the degraded original battery cannot sustain without voltage sag. When pack voltage dips under load, the radio module loses stable supply voltage and the Bluetooth connection drops or stutters. This is not a pairing issue — it is a power delivery issue. A fresh pack rated to the full 10200mAh capacity handles the combined draw without the sag that triggers the dropout.

Omni Jacket won't wake from USB-C charge after sitting unused for months

If the speaker sat discharged for an extended period, the individual 18650 cells may have dropped below the USB-C PD minimum acceptance voltage — typically around 2.5V per cell. At that point, the charger cannot initiate a charge handshake and the speaker appears completely dead. Connect it to a USB-A 5V source instead of a USB-C PD charger, which applies a slow trickle charge and can recover cells in the 2.5–3.0V range. Once cell voltage climbs back above 3.0V, normal USB-C charging resumes.