Hello guys,

I have a battery of 3.7V 500mAh. I want to charge it with a 5V 80mA Solar Cell. How long does it take to charge the battery? after charging can I use the battery to charge my 4000mAh phone? if yes, how much percentage will it charge? Please help, thank you.

 

A perfect battery would charge in 500mAh/80mA=6.25 hours. A real battery probably about 25% longer. A real solar cell in real weather might take a lot longer!
Is the battery in your phone also 3.7V? If so the maximum it could possibly contribute would be 500mAh/4000mAh = 12.5%. In real life, because the charging voltage is higher than the discharge voltage, you would be lucky to get 10%.

 

A perfect battery would charge in 500mAh/80mA=6.25 hours. A real battery probably about 25% longer. A real solar cell in real weather might take a lot longer!
Is the battery in your phone also 3.7V? If so the maximum it could possibly contribute would be 500mAh/4000mAh = 12.5%. In real life, because the charging voltage is higher than the discharge voltage, you would be lucky to get 10%.

Thank you very much.