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I got a 50W panel. Unfortunately, I couldn't make a perfect measurement without tools, but I'll write down what I did. For the measurement, I created an Arduino + Photoresitor. I put a display on it that measures between 0-9. 0: little light (sunset, sunrise), 9: I light directly on the solarresitor with strong led light. As a consumer, I used a 5V powerbank that can be charged with 1A. Powerbank consumption ~120mA from the network with my measuring tools. Panel results: 9:75-100mA, 8:6-74mA, <=7: I couldn't measure it. I'm afraid that the measuring instrument takes off too much, since it didn't charge the powerbank with 10A measurements and only 120mA is measurable. Without a measuring instrument, a USB lamp is fully lit even at 7 brightnesses. The brightness may have gone below 7, but unfortunately my Arduino instrument gave in, and in Hungary at 6:30 on October 29, the light was quite tolerable.
Chegou rápido no Brasil. Anteriormente já havia comprado outros 2 painéis, agora comprei mais 2. Liguei 2 em paralelo e em série com outros 2 em paralelo, para obter tensão maior com corrente maior. Utilizo um MPPT MPPT5025A-DUO MPPT 25A 12V comprado também na BANGGOOD que reduz a tensão e aumenta a corrente de carga da bateria. O painel SP-P50 produz na realidade de 35W a 40W. O painel é robusto pois suportou o maltrato do transporte. Olhe nas fotos como chegou a embalagem. Nos anteriores a embalagem foi muito melhor. Recomendo a BANGGOOD melhorar a embalagem atual. Gostei muito dos painéis.