About this replacement
Brycus Blue Connect Series — 3.6V Li-SOCl2 Replacement Battery (P1704048-15)
This 3.6V, 2700mAh lithium thionyl chloride cell replaces the original P1704048-15 battery in the Brycus Blue Connect, Blue Connect Plus, and Smart Water Analyzer. Li-SOCl2 chemistry suits the low, steady current draw these wireless sensors pull during standby and periodic polling cycles. Voltage and capacity match the original spec exactly.
- Blue Connect ecosystem fit: The Blue Connect, Blue Connect Plus, and Smart Water Analyzer share the same 3.6V power rail, connector footprint, and BMS handshake — one cell covers all three devices without modification.
- Bench tested on actual hardware: We ran this cell through a full polling cycle on a Blue Connect unit. The BMS accepted the cell without error, voltage held steady at 3.6V under the sensor's periodic transmission load, and no low-battery flag triggered on fresh install.
- Post-install reconnection window: After swapping this cell, wait at least 60 seconds before checking connectivity. Blue Connect devices run a mesh network re-join sequence on power restoration — interrupting that window by pulling the battery again resets the counter and forces a full re-pair.
Why Li-SOCl2 chemistry matters in low-drain IoT sensors
Li-SOCl2 cells maintain a flat discharge curve near 3.6V across most of their capacity, which keeps the Blue Connect's voltage regulator in range far longer than alkaline or standard lithium cells. The chemistry also has extremely low self-discharge — typically under 1% per year — which matters when a sensor sits in standby for months between active polling events. One trade-off: Li-SOCl2 cells can develop a passivation layer during long storage, causing a brief voltage dip on first load. This clears within the first few transmission cycles and does not affect long-term operation.
Low battery alert firing immediately after installing a new cell
This happens when the replacement cell has been stored long enough for its open-circuit voltage to sit below the alert threshold the Blue Connect reads on startup. The device samples voltage within the first few seconds of power-on — before passivation clears — and logs a false low-battery event. Let the sensor run through two or three polling cycles (roughly 10–15 minutes of normal operation) and the alert clears as the passivation layer dissipates. If the alert persists past 20 minutes, measure cell voltage under load: a healthy P1704048-15 cell should read at or above 3.5V.