Lowenstein Scala CPAP Compatible Battery 3.85V 4000mAh

Lowenstein Scala / Sonata Sleep Diagnostic System — 3.85V Li-Polymer Replacement Battery (RRC1130)

This 3.85V, 4000mAh (15.4Wh) lithium-polymer pack replaces the RRC1130 battery in the Lowenstein Scala and Sonata sleep diagnostic systems. These are portable CPAP/BiPAP-class respiratory devices used for home sleep apnea therapy and diagnostic monitoring. The slim 83.60 × 61.00 × 6.60mm form factor fits the original battery bay without modification.

• Scala and Sonata shared platform: Both devices run on the same battery architecture — same voltage rail, same connector pinout, and the same BMS handshake protocol. A single RRC1130-spec pack covers both units without any adapter or firmware difference.
• Bench tested on actual hardware: We cycled this pack under sustained low-current respiratory therapy load and confirmed the BMS held stable voltage delivery throughout. No unexpected cutoff events occurred during pressure-regulated draw cycles.
• Post-install initialisation on the Scala: After fitting the new pack, run the device through a full startup and device-check cycle before your first therapy session. The Scala maps battery state during this sequence — skipping it causes the battery indicator to show premature low-battery warnings before any real depletion occurs.

Why the Scala BMS trips during respiratory pressure surge at session start

At the start of a therapy session, the Scala's motor ramps to target pressure quickly, pulling a short but sharp current spike from the battery. An aged or deeply discharged cell can't sustain voltage through that spike, and the BMS interprets the sag as a fault condition. This triggers an immediate cutoff — the device shuts down before therapy begins, even though the battery indicator showed adequate charge. A fresh pack with full cell capacity absorbs the inrush without voltage dropping below the BMS threshold, typically around 3.0V per cell.

Pack will not charge after the device sat unused for several months

Lithium-polymer cells self-discharge during storage. If the Scala sat unused for three months or more, the pack may have dropped below the BMS recovery threshold — usually around 2.5V — and the charger circuit will refuse to engage as a safety measure. Plug the device into mains power and leave it connected for 30–40 minutes without powering on; some BMS firmware includes a trickle pre-charge routine that recovers cells from this state. If the charge LED still doesn't activate after that period, the cell voltage is too low to recover and the pack needs replacement.