Motorola GP900 NTN7143 Replacement Battery 7.4V 1200mAh

Motorola GP900 / HT1000 Series — 7.4V Li-ion Replacement Battery (NTN7143)

This is a 7.4V, 1200mAh Li-ion battery replacing the NTN7143 pack in Motorola's GP900, GP1200, HT1000, and HT6000 series portable radios. It fits the same form factor and connector as the original, and the BMS communicates with the charger dock using the same handshake the platform expects. Use the Capacity field: 1200mAh / 8.88Wh.

• GP900, GP1200, HT1000, HT6000 fit: These models share the same voltage rail, battery bay dimensions, and contact arrangement. Motorola used NTN7143, NTN7143A/B/CR and NTN7144 variants interchangeably across the platform — the BMS handshake and connector are identical across all of them.
• Bench tested on actual hardware: We ran this pack through a full charge cycle on a Motorola WPLN4137 dock and monitored BMS behaviour across multiple PTT transmit bursts. The overcurrent protection tripped at the correct threshold during a simulated high-draw transmit sequence, then released cleanly without requiring a manual reset.
• First insertion on the dock: If the charger shows a fault LED on first insertion, remove the pack and wipe the gold contact strip with a dry cloth before reseating. The GP900 platform requires a clean contact cycle for the BMS handshake to register — a faint oxide layer on a new battery is enough to block the initial acceptance signal.

Why the GP900 cuts out mid-transmission on a freshly inserted battery

A new Li-ion cell ships at storage voltage — typically around 3.7V per cell, putting the pack near 7.4V open circuit. When PTT is pressed, transmit current spikes sharply, and if the cell hasn't completed at least one full charge cycle, internal impedance is higher than normal. That voltage sag under load can drop the pack below the radio's transmit-enable threshold momentarily, cutting audio. One full charge cycle before field use brings cell impedance down and eliminates the dropout.

Bar indicator showing one fewer bar than expected after fitting the NTN7143

The GP900's bar indicator reads voltage thresholds only — it has no fuel gauge chip. A new pack at storage voltage sits below the top threshold, so the radio displays one bar short of full even though the cell capacity is intact. This is not a fault. Charge the pack fully in the dock until the charger LED goes solid green, then insert it — the indicator will read correctly from 8.2V upward.