Gama Sonic GS37V20 Solar Light Replacement Battery 3.7V 2600mAh

Gama Sonic GS37V20FLT — 3.7V Li-ion Replacement Battery (GS37V20)

This is a 3.7V 2600mAh Li-ion replacement battery for the Gama Sonic GS37V20FLT solar light fixture. It stores energy from the fixture's integrated solar panel during the day and powers the light through the night. When the original cell degrades and the light dims or stops holding charge, this is the direct replacement.

• GS37V20FLT compatibility: The GS37V20FLT uses a dedicated battery bay sized for the 65.80 × 22.50 × 18.60mm cell format. The BMS in this fixture communicates directly with the battery on a single voltage rail at 3.7V nominal — swapping to a different voltage or form factor trips the protection circuit and the light won't activate.
• Bench tested on actual hardware: We cycled this cell through solar-input charge sequences and monitored the BMS handshake at charge cutoff. The protection circuit engaged cleanly at full capacity with no thermal event, and the low-voltage cutoff held at the correct floor to protect cell integrity.
• Solar panel alignment on the GS37V20FLT: Position the panel face perpendicular to direct sunlight. The GS37V20FLT's integrated panel outputs between 100–300mA depending on angle — if it drops below the BMS minimum input threshold due to shading or a shallow angle, the battery will not charge even in bright ambient light.

Why the GS37V20FLT stops charging through the solar panel

The GS37V20FLT's BMS requires a minimum input current to initiate a charge cycle — the integrated panel only meets that threshold under direct, unobstructed sunlight. Dust accumulation on the panel surface, partial shading from nearby foliage, or a mounting angle more than 30° off perpendicular can drop panel output enough that the BMS never opens the charge gate. The battery sits at whatever state of charge it was last at and does not top up across the day. Clean the panel surface and verify the fixture has a full clear-sky exposure window before assuming the battery has failed.

GS37V20FLT light dims and shuts off before sunrise

This symptom points to a partially charged cell that exhausts capacity before the night cycle completes. The root cause is usually insufficient solar input during the preceding day — overcast conditions, short winter daylight hours, or panel shading reduce the charge delivered to well below the 2600mAh cell capacity. A cell that was only charged to 40–50% of capacity will hit the BMS low-voltage cutoff early in the night cycle. If multiple consecutive clear-sky days do not resolve it, measure the resting voltage of the installed cell — a healthy charged cell should read 4.1–4.2V; anything below 3.5V after a full day of sun indicates cell degradation and replacement is needed.