About this replacement
Airbus TPH900 — 3.7V Li-ion Replacement Battery (HR8940AAA04)
This is a 3.7V, 3600mAh Li-ion replacement battery for the Airbus TPH900 portable two-way radio. It carries OEM part numbers HR8940AAA04 and VKB56468 702 013. The cell fits directly into the TPH900 battery bay and communicates with the radio's BMS over the standard contact strip.
- TPH900 platform fit: The TPH900 operates on a single-cell 3.7V lithium-ion architecture with a multi-pin contact interface that carries both power and BMS data. The replacement cell matches that voltage rail and connector pinout exactly, so the radio's charge and discharge logic runs without modification.
- Bench tested on actual hardware: We cycled this pack through transmit and receive loads on the bench. The BMS held cutoff at the correct thresholds under both sustained PTT draw and standby current, with no false overcurrent trips during the high-current transmit spike.
- First-insertion contact check: If the TPH900 charger dock shows a fault LED on first insertion, remove the battery and wipe the gold contact strip with a dry cloth before reseating. The dock requires a clean contact cycle to complete the BMS handshake before it will begin charging.
Why the TPH900 cuts out mid-transmission on a new battery
When PTT is pressed, transmit current spikes sharply — often two to three times the standby draw. If the battery contacts are contaminated or the BMS has not completed its initialisation handshake with the radio, that current spike can trip an overcurrent flag and drop the transmission. This is not a cell fault. It is a contact or handshake issue. Clean the contact strip, reseat the pack firmly, and allow the radio to sit powered on for 60 seconds before transmitting to let the BMS settle.
Bar indicator showing fewer bars than expected after fitting a new pack
New Li-ion cells ship at storage voltage — typically around 3.6V to 3.75V — which sits below a full-charge reading on the TPH900's voltage-threshold bar indicator. The radio reads cell voltage and maps it to bars, so a new uncharged pack will display one or two bars even though the cell is not depleted. This is not a fault. Seat the battery in the dock and run a full charge cycle first. The bar indicator should read full once the cell reaches approximately 4.2V.