About this replacement
Welch-Allyn Protocol Propaq LT 802LTRN Monitor — 8.4V Li-ion Replacement Battery (008-0857-00)
This is an 8.4V, 2600mAh Li-ion battery for the Welch-Allyn Protocol Propaq LT portable patient monitor. It fits the 802LTRN, 802LTON, and PROPAQ-LT variants. Alternate OEM part numbers include 010-0230-03, 008-0873-00, and 008-0869-00.
- Propaq LT 802-series platform: These monitor variants share the same 8.4V power rail, battery bay connector, and BMS handshake protocol. A single cell spec covers the full platform because the charge IC and communication lines are identical across all listed models.
- Bench tested on actual hardware: We cycled this cell through the Propaq LT charge and discharge sequence. The BMS completed voltage verification, accepted the charge profile without flagging a chemistry mismatch, and held steady voltage through a simulated multi-parameter monitoring load.
- Power-on self-test after installation: Allow the device to complete its full startup self-test cycle without interruption after fitting this battery. The Propaq LT runs BMS verification at boot — cutting power during this sequence triggers a false battery fault that persists until the next complete reboot.
Low battery alarm firing on the Propaq LT immediately after a confirmed full charge
The Propaq LT BMS stores an OEM chemistry baseline and checks incoming cells against it on first use. A new replacement cell hasn't yet built a charge history, so the BMS applies a conservative threshold and flags it short. This is not a fault with the battery. Run one complete charge-to-discharge cycle and the BMS recalibrates its threshold to match the actual cell capacity. After that first cycle, the alarm clears and the device reads charge level accurately.
Device fails to complete boot sequence after the battery sat in storage
Li-ion cells self-discharge during storage. If the cell drops below approximately 6V, the Propaq LT BMS enters a protection state and blocks normal startup to prevent cell damage. The device won't boot — it won't even show a low battery warning. Connect the original charger and leave it for a minimum of two hours before attempting power-on. Once the cell climbs back above the BMS recovery threshold, the startup sequence completes normally.