Standard Horizon HX870 Replacement Battery SBR-13LI 7.4V

Standard Horizon HX870 / HX890 — 7.4V Li-ion Replacement Battery (SBR-13LI)

This is a 7.4V, 1100mAh Li-ion battery for the Standard Horizon HX870, HX870E, and HX890 handheld VHF marine radios. It replaces OEM part number SBR-13LI and fits the same battery bay without modification. The HX870 and HX890 are compact maritime transceivers used for vessel-to-vessel and vessel-to-shore communication on the water.

• HX870, HX870E, and HX890 compatibility: All three models share the same 7.4V two-cell Li-ion bay, connector pinout, and BMS handshake protocol. One battery pack covers the full group — no model-specific variants required.
• Bench tested on actual hardware: We ran the SBR-13LI replacement through charge and transmit cycles on the HX870. The BMS accepted the dock charge signal on first insertion and held the voltage rail steady through repeated PTT press cycles without cutoff.
• Dock seating on first use: If the charger shows a fault LED on first insertion, remove the battery and wipe the contact strip with a dry cloth. The HX870 dock requires a clean contact surface to complete the BMS handshake before it will begin charging. Reseat firmly until the pack clicks into position.

HX870 transmit current spike and BMS overcurrent response

The HX870 draws a short, sharp current spike the moment PTT is pressed — the transmitter pulls hard before the RF output stabilises. A battery BMS with a tight overcurrent threshold can interpret this spike as a fault and cut the pack momentarily. This shows as a brief dropout at the start of each transmission. The replacement SBR-13LI BMS is tuned to the HX-series transmit profile and handles the inrush without triggering a cutoff.

Bar indicator showing one fewer bar than expected on a new pack

A new Li-ion cell ships at storage voltage — typically around 3.7V to 3.8V per cell, not the full 4.2V per cell the radio expects at 100% charge. The HX870 uses voltage thresholds to drive the bar indicator, so a new battery at storage charge will display one bar short of full immediately after insertion. This is not a capacity defect. Charge the pack fully in the HX870 dock before first use and the indicator will read correctly once the cells reach 8.4V total.