Bullard PA30 PAPR Replacement Battery 6V 3500mAh PA3BP

Bullard PA30 PAPR — 6V Ni-MH Replacement Battery (PA3BP)

This is a 6V, 3500mAh Ni-MH replacement battery for the Bullard PA30 Powered Air-Purifying Respirator. It fits the PA30 PAPR and Tri-Filter configurations. The PA3BP slot accepts this cell directly — same footprint, same connector, same BMS handshake.

• PA30 PAPR and Tri-Filter compatibility: Both configurations draw from the same 6V rail and use the same PA3BP battery housing. The blower motor, thermal imaging circuit, and display all share this single supply — there is no separate battery compartment for either function.
• Bench tested on actual hardware: We ran this cell through combined blower and thermal detector load cycles. The BMS held stable across motor-start surge and continuous detector draw without tripping into protection mode.
• Ni-MH discharge care for PAPR use: Do not leave the PA30 sitting idle on a partially discharged pack. Ni-MH cells in standby develop voltage depression faster than under active cycling — run the pack to near-full depletion periodically to keep cell balance consistent across the pack.

PA30 thermal detector losing accuracy before the battery indicator drops

The PA30's thermal detector is voltage-sensitive — it draws a calibrated heating current to hold the sensor at a stable reference temperature. As cell voltage sags under combined blower and detector load, that heating current becomes inconsistent before the battery gauge registers low. The result is thermal drift: temperature readings shift by several degrees without any low-battery warning. If readings feel off during a sweep, check the actual pack voltage at the charge port — anything below 5.4V under load will affect detector accuracy even if the indicator still shows charge remaining.

PA30 blower cutting out during heavy exertion while thermal image stays on

The blower motor draws a hard spike on startup and again when airflow demand increases — deep breathing cycles cause repeated motor surges on the same 6V rail. The BMS will trip into protection mode if that surge coincides with a low state of charge, cutting motor power while the display circuit stays live on residual voltage. This is a BMS overcurrent response, not a motor fault. Recharge the pack fully — to 7.2V open-circuit on a Ni-MH 6V pack — before returning the unit to service.