About this replacement
Edan M3 / M3A Vital Signs Monitor — 14.8V Li-ion Replacement Battery (TWSLB-009)
This is a 14.8V, 2600mAh (38.48Wh) Li-ion replacement for the TWSLB-009 battery used in the Edan M3 and M3A Vital Signs Monitors. These are portable clinical patient monitors used to track SpO2, NIBP, ECG, and temperature at the bedside or during patient transport. Voltage and cell chemistry match the OEM specification.
- M3 and M3A compatibility: Both monitors share the same 14.8V battery bay, connector pinout, and BMS handshake protocol — the TWSLB-009 part number covers the full M3 platform without modification.
- Bench tested on actual hardware: We cycled this battery through the M3's power-on sequence and confirmed the BMS completes charge authentication, reports state-of-charge correctly to the monitor's battery icon, and holds the 14.8V nominal rail under the device's combined sensor load.
- Post-swap startup procedure: After installing a new battery, allow the M3 to complete its full power-on self-test without interruption. The monitor runs a BMS verification pass at boot — cutting power during this sequence locks in a false battery fault that persists until the next clean reboot cycle.
Device not completing boot sequence after battery swap
The M3 runs a multi-stage self-test at startup that includes a BMS authentication check against the installed battery. A cell that has been in storage can sit below the threshold the monitor expects at boot, causing the sequence to stall or loop. This is not a fault with the battery or the device — it is the BMS flagging a low state-of-charge before the cell has been brought up to a verified level. Charge the replacement battery to full before the first installation, then power on without removing the charger until the self-test completes.
Battery icon not reaching 100% on the M3 display after first full charge
The M3's charge IC applies a conservative current limit on new cells during the first charge cycle — this is intentional. The charge algorithm recalibrates its capacity estimate against actual cell behaviour over the first full charge-discharge cycle, so the reported percentage may cap below 100% initially. Run one complete charge-to-full, use the monitor until the low battery alert triggers, then recharge fully. After that cycle, the state-of-charge display tracks accurately to the 2600mAh cell capacity.