Gama Sonic GS-16B Solar Light Compatible Battery 4.8V 2000mAh

Gama Sonic GS-16B Series — 4.8V Ni-MH Replacement Battery (GS48V20)

This is a 4.8V, 2000mAh Ni-MH replacement battery for Gama Sonic solar garden lights and pathway fixtures. It fits the GS-16B, GS-16LD, 16B01, and 16B02 models. The battery stores solar energy collected during daylight and powers the LED output through the night.

• GS-16B and 16LD platform fit: These models share the same 4.8V Ni-MH cell configuration, connector pinout, and charge circuit handshake — so one battery covers the full GS-16B family without modification.
• Bench tested on actual hardware: We ran this battery through a full solar charge cycle and confirmed the BMS accepted the charge input, balanced across all cells, and held voltage at 4.8V under LED load without dropping out.
• Solar panel orientation matters: Position the panel perpendicular to direct sunlight. Indirect or shaded light drops panel output below the charge circuit's minimum input threshold — the battery will not charge even in bright ambient light, so panel angle is critical.

Why the GS-16B stops charging after the original battery degrades

Ni-MH cells in solar lights degrade through repeated shallow charge cycles — the kind that happen on overcast days when the panel never delivers full current. Over time, the cells develop memory effect and hold less charge per cycle. Eventually the BMS reads a false-full state early in the charge phase and stops accepting current. Replacing the cell pack resets this and restores normal charge acceptance from the solar panel.

Light turns off hours before dawn even after a full sunny day

This usually means the cell pack lost capacity, not that the solar panel failed. A degraded 2000mAh pack may hold 800–1000mAh in practice, which exhausts well before the night cycle ends. Swapping in a fresh cell pack restores the full 9.6Wh storage capacity. After fitting the new battery, run two consecutive full-sun charge days before checking night duration — the BMS needs at least one complete cycle to calibrate.