The 20W 12V solar panel’s small size makes it perfect for trailers, camping, signage, electric sheep, and other places without power. It is best for short-term energy use in areas without network connections.
[pdf] Silicon Cell Photovoltaic Module monocrystalline (sc-Si), Non Standard series, from the manufacturer SOLAR INNOVA, maximum power (Wp) 250 W, voltage at maximum power (Vmp) 36.20 V, current at maximum power (Imp) 6.91 A, open circuit voltage (Voc) 44.60 V, short circuit current (Isc) 7.32 A, efficiency 15.38%, composed of 72 cells, front layer tempered glass thick 3.2 mm, encapsulating layers of cells of EVA, back layer of TPT, anodized aluminum frame AL-6063-T5, junction box (diodes, cables 4 mm2, 900 mm and connectors MC4-T4), working temperature -40/+85 ºC, dimensions 992x1640 mm, maximum wind load 2400 Pa, maximum snow load 5400 Pa, weight 18.15 kg.
[pdf] So while PV modules continue to increase in output, portable 40 watt solar panels remain appealing for people who do not need a lot of power. If you have reasonable expectations, this panel can charge.
[pdf] 
