Sirius SXi1 Replacement Battery 3.7V 1250mAh Li-ion

Sirius SXi1 / XM Lynx — 3.7V Li-ion Replacement Battery (SX-6900-0010)

This is a 3.7V, 1250mAh Li-ion replacement battery for the Sirius SXi1 and XM Lynx portable satellite radio receivers. It slots directly into the original battery bay and uses the same OEM part number SX-6900-0010 footprint at 54.50 × 33.90 × 5.50mm. Both devices share the same battery bay, connector orientation, and voltage requirement.

• SXi1 and XM Lynx compatibility: These two receivers use the same battery bay, voltage rail, and connector pinout. Sirius cross-listed the SX-6900-0010 across both platforms — the hardware is electrically identical at the battery interface, so one replacement covers both units.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the SXi1 platform. The BMS accepted the charge handshake without fault flags, held voltage through the DAB decoder load, and cut off cleanly at the low-voltage threshold without triggering a hard shutdown loop.
• Post-swap scan on DAB receivers: After fitting this battery, let the radio complete a full auto-scan before manually tuning. DAB receivers store station lists in volatile memory — any power interruption clears that list. A fresh auto-scan rebuilds it and restores normal station access.

Radio cutting out mid-station at low battery on the SXi1

The DAB decoder in the SXi1 requires a stable voltage supply to process the OFDM stream. When the cell voltage sags below roughly 3.4V under RF load, the decoder loses enough headroom to sustain stream decoding and the audio drops. This looks like poor reception or a weak signal, but the actual cause is voltage sag — not aerial position. A fresh cell with low internal resistance holds voltage steady under that combined RF and decoder load.

Shorter battery life when the SXi1 is used in weak signal areas

In areas with marginal satellite signal, the SXi1 increases its RF search and acquisition power draw to maintain lock. That extra current draw accelerates cell depletion compared to use in strong-signal areas. If the original battery was lasting well at home but draining fast on the move, this is the cause — not a defective replacement. Keeping the aerial unobstructed reduces the power the radio needs to maintain signal lock.