Honeywell BAT-IAQ HAQSPA Replacement Battery 3.7V 2600mAh

Honeywell HAQSPA / HAQSPA-R Air Quality Meter — 3.7V Li-ion Replacement Battery (BAT-IAQ)

This is a 3.7V, 2600mAh Li-ion replacement battery for the Honeywell HAQSPA and HAQSPA-R portable air quality meters. It replaces OEM part number BAT-IAQ. The HAQSPA series is a handheld indoor environmental monitoring instrument used for surveying particulate matter, CO₂, humidity, and temperature across occupied spaces.

• HAQSPA and HAQSPA-R compatibility: Both variants run the same 3.7V power rail and use an identical connector and BMS handshake. The BAT-IAQ part number covers both. No hardware modification is needed to swap between units.
• Bench tested on actual hardware: We cycled this pack through the HAQSPA's multi-sensor initialisation sequence, which pulls a brief current spike as the particulate laser and CO₂ module power up simultaneously. The BMS handled the inrush without tripping. Sustained sensor load across a logging session held voltage within the instrument's operating threshold.
• First-use calibration step: After fitting this battery, run a full calibration cycle through the HAQSPA instrument menu before field deployment. The meter maps battery state during calibration, and skipping this step causes premature low-battery warnings to appear during your first measurement session.

BMS lockout after the HAQSPA sat unused in a carry case for months

Li-ion cells self-discharge during storage. If the HAQSPA sits unused long enough, the pack voltage can drop below the BMS's minimum recovery threshold — typically around 2.5V per cell. At that point the BMS locks out charge current entirely and the instrument appears completely dead. To recover, connect the charger and leave it for 20–30 minutes without interruption; most BMS circuits include a trickle pre-charge stage that runs below normal charge voltage to pull the cell back into the recoverable range before full charge begins.

HAQSPA powering off mid-logging session with no low-battery warning

This is a voltage sag failure, not a capacity failure. Under sustained load from simultaneous CO₂ sampling, particulate counting, and data logging, an aged or partially discharged cell can sag below the instrument's minimum operating voltage for a fraction of a second — enough to trigger an immediate shutdown. The fuel gauge may still read 30–40% at the point of cutoff because it was tracking open-circuit voltage, not loaded voltage. Fitting a fresh cell and confirming charge at 4.1–4.2V before a logging session eliminates this failure mode.