Diode help and general question

[Ddiamonds]

Putting together a solar charger for usb charging. Panel puts out 4.7v so was wondering what im guessing diode i would need to put in line before the usb female plug. Also if thats gonna effect my voltage much. Thanks

 

[Alec_t]

Any diode will drop voltage, so you will have only 4.0V (for a normal silicon diode) or 4.4V (for a Schottky diode) after the diode.
USB is rated at 5V.
An 18650 lithium cell needs 4.2V for full charge.
Welcome to EP!

 

[cjdelphi]

Putting together a solar charger for usb charging. Panel puts out 4.7v so was wondering what im guessing diode i would need to put in line before the usb female plug. Also if thats gonna effect my voltage much. Thanks

with a diode you might not reach full charge and only charge 95% or something which as far as I'm concerned can't be too bad for the cell, they say not to leave them charged over night but I think that's bs as I leave all my cells fully charged and the cell is just fine

 

[kellys_eye]

Panel puts out 4.7v

When?

If the sunlight varies, so does the output voltage.

 

[CircutScoper]

...they say not to leave them charged over night...

Overnight charging shouldn't be too much of a problem when the source is a solar panel, anyway.

 

[cjdelphi]

Overnight charging shouldn't be too much of a problem when the source is a solar panel, anyway.

no I don't suppose it would with a solar panel lol