FT Series Supercapacitors KEMET FT Series Supercapacitors, also known as Electric Double-Layer Capacitors (EDLCs) are intended for high energy storage applications. These supercapacitors offer a wide operating temperature range from -40°C to +85°C. The FT supercapacitors also feature a maximum operating voltage of 5.5VDC and high reliability against liquid leakage. KEMET FT Series Supercapacitors are lead-free and RoHS compliant.