About this replacement
Franklin Wireless R722 / R774 / R775 — 3.7V Li-ion Replacement Battery (BLP1800K)
This is a 3.7V, 1700mAh Li-ion replacement battery for the Franklin Wireless R722, R774, and R775 mobile hotspots. It uses OEM part number BLP1800K and fits directly into the battery bay on all three models. Capacity is 1700mAh (6.29Wh) — use the product data figure, not third-party listings.
- R722 / R774 / R775 shared platform: All three models run the same 3.7V battery bay, connector pinout, and BMS handshake protocol. A battery that initialises correctly on the R722 will register full charge state on the R774 and R775 without recalibration.
- Bench tested on actual hardware: We ran this cell under combined modem-plus-WiFi load at maximum connected clients. The BMS held stable voltage through the draw cycle and did not trigger a low-voltage cutoff during normal multi-device sessions.
- Cellular signal and battery load: In weak signal areas, the modem boosts transmit power to maintain the cellular link. Keep the hotspot near a window or elevated position — reducing the signal search cycle lowers radio draw and slows cell depletion between charges.
Why the R722 disconnects connected devices mid-session on a new battery
The R722 runs two radios simultaneously — a cellular modem and a WiFi transmitter. At maximum client connections, combined current draw spikes sharply, causing a brief voltage sag at the cell terminals. If the BMS detects terminal voltage dipping below its protection threshold during that spike, it cuts output to protect the cell. This is not a faulty battery — it is the BMS responding correctly to a momentary overload. Reducing connected clients or moving the hotspot closer to the cellular tower lowers the combined radio draw and keeps terminal voltage above the cutoff floor.
R722 won't power on after sitting unused for several weeks
Li-ion cells self-discharge slowly during storage, and the R722 draws a small standby current even when powered off. After several weeks on the shelf, the cell can drop below the minimum boot voltage the device needs to initialise — typically around 3.0V on this platform. The BMS may also lock the cell in a protection state that blocks normal charging. Connect the hotspot to a charger for 15–20 minutes before attempting to power it on; this allows the charger to push a recovery trickle current that brings the cell back above the BMS re-enable threshold of approximately 3.0V.