About this replacement
Additel 22XA / ADT 220 / ADT 221A / ADT 222A Multifunction Calibrator — 7.4V Li-Polymer Replacement Battery (9712, 9702)
This 7.4V 3200mAh lithium-polymer pack replaces OEM part numbers 9712 and 9702 in the Additel 22XA, ADT 220, ADT 221A, and ADT 222A multifunction calibrators. These instruments generate precise electrical signals for pressure, temperature, and process measurement calibration in the field. Same voltage rail, same connector, same BMS handshake as the factory pack.
- 22XA and ADT 220 / 221A / 222A platform fit: All five models share the same 7.4V battery bay, connector pinout, and BMS communication protocol — one pack covers the entire family without modification.
- Bench tested on actual hardware: We cycled this pack through repeated probe initialisation sequences and sustained signal-generation loads. The BMS held voltage within spec across the full discharge curve and did not trip during the current spike at sensor power-up.
- First-use calibration cycle: After installing, run a full calibration cycle through the instrument menu before field deployment. The 22XA maps battery state during calibration, and skipping this step causes premature low-battery warnings during the first measurement session.
BMS cutoff when the ADT 220 initialises a probe or sensor module
When the calibrator powers up a connected probe, there is a brief current spike as the sensor module initialises. A weakened or deeply discharged original battery can drop below the BMS undervoltage threshold during this spike, causing an immediate shutdown before any measurement is taken. This pack's cells maintain a tighter voltage floor under transient load, so the BMS does not interpret the initialisation draw as an unsafe drop. If the shutdown persists after fitting the new pack, check that the probe connector is fully seated — a partial connection increases contact resistance and amplifies the spike.
Additel calibrator shows inconsistent battery percentage after reboot
The 22XA's battery indicator uses voltage thresholds to estimate state of charge. A new cell has a slightly different discharge curve compared to the worn pack it replaces, so the display may jump or read high for the first several cycles. This is not a fault — the instrument is recalibrating its voltage-to-percentage mapping to the new cells. Run three full charge-discharge cycles through normal use, and the percentage reading will stabilise. If it remains erratic after three cycles, measure the pack voltage directly; a healthy cell at rest reads between 7.2V and 8.4V.