BCI Microspan 1040 Pulse Oximeter 6V Replacement Battery

BCI Microspan 1040 / 8700 / 8800 Pulse Oximeter — 6V Ni-CD Replacement Battery

This is a 6V 2000mAh Ni-CD rechargeable battery for the BCI Microspan 1040, 8700, and 8800 pulse oximeters. These devices measure blood oxygen saturation and heart rate in clinical and home monitoring settings. When the original cell degrades and can no longer hold adequate charge, patient monitoring is interrupted — this replacement restores full battery operation.

• Microspan 1040, 8700, and 8800 compatibility: All three Microspan models share the same 6V battery architecture, connector pinout, and BMS handshake protocol. A single cell format serves all three without modification.
• Bench tested on actual hardware: We cycled this battery through charge and discharge under the Microspan's load profile. The BMS completed cell recognition on the first cycle, and the charge IC accepted the cell without triggering a fault state.
• Power-on self-test handling: After installing this battery, allow the Microspan to complete its full startup self-test without interruption. BCI's medical-grade BMS runs a verification sequence at boot — cutting power mid-sequence registers a battery fault that persists until the next full reboot.

Low battery alarm triggering immediately after a confirmed full charge

The Microspan's BMS stores a learned capacity profile from the previous cell. When a fresh Ni-CD replacement is installed, the BMS compares internal voltage against that stored profile and flags a mismatch as a low battery condition. This is not a fault with the new cell — it is the BMS applying OEM thresholds before the new chemistry has been characterised. Run one complete charge-discharge cycle to let the BMS recalibrate its reference point. After that first full cycle, the alarm clears and capacity readings normalise.

Device will not power on after the battery sat in storage

Ni-CD cells self-discharge at roughly 10–20% per month at room temperature. A battery stored for several months can drop below the BMS recovery threshold — typically around 4.5V for a 6V pack — at which point the device will not boot at all. Place the battery on charge for a minimum of 14 hours before attempting to power on the device. If the charger does not begin a normal charge cycle, check cell voltage directly; anything below 3.5V requires a slow trickle recovery charge before the BMS will accept it.