Retevis H777 Compatible Battery 3.7V 900mAh Li-ion

Retevis H777 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 900mAh Li-ion replacement battery for the Retevis H777 UHF two-way radio. It fits the compact H777 handset used in commercial, security, and recreational short-range comms. Swap it in when the original pack no longer holds a charge through a full shift.

• H777 platform fit: The H777 uses a fixed-footprint battery bay with a three-point contact strip. This pack matches that contact layout and the 3.7V nominal rail the radio's TX circuitry expects. No contact bending or adapter needed.
• Bench tested on actual hardware: We ran this pack in an H777 handset and cycled PTT under sustained transmit loads. The BMS held the output rail steady across repeated keying bursts and released cleanly after each transmission without triggering overcurrent lockout.
• First insertion into the charger dock: If the dock LED shows a fault on first insertion, remove the pack and wipe the gold contact strip with a dry cloth before reseating. New cells ship at storage voltage — the dock needs a clean contact cycle to accept the BMS handshake and begin charging.

Why the H777 cuts out mid-transmission on a new battery

The H777 draws a sharp current spike the moment PTT is pressed as the RF output stage ramps up. If the battery contacts have any surface oxidation or debris, voltage at the radio's power rail drops below the TX threshold for a split second — long enough for the radio to cut the transmission. This is not a faulty cell. Clean both the battery contacts and the radio's contact pins with a dry cloth, then reseat the pack firmly. A solid mechanical connection eliminates the transient voltage drop that causes the cutout.

H777 bar indicator shows one bar on a fully charged new pack

New Li-ion cells ship at approximately 3.6–3.7V storage voltage, not the 4.1–4.2V they reach after a full charge cycle. The H777's voltage-threshold bar indicator reads that storage voltage as a low charge state — one bar is expected at this point, not a sign the pack is defective. Place the battery in the charger and run a complete charge cycle before judging capacity. After a full charge, the indicator should advance to its maximum bar reading.