Solar Charge -lighting circuit design help

Thread Starter

jybrooks

Joined Jan 17, 2017
4
I am trying to build a simple solar panel charging circuit that uses a 5V output solar cell, a 3.7V Li/ion battery and a 3 LED lamp. Simply, the solar panel charges the battery during sunlight, light lights using battery during dark. Anyone have something simple?
 

mcgyvr

Joined Oct 15, 2009
5,394
Define simple?
Charging a lithium battery is best done with an IC intended for that function as its very critical that charging is done properly to avoid fires,etc...

"simple" may be to just use a TP4056 module available on ebay,etc... or similar
 

Jan Luthe

Joined Jan 10, 2015
72
I am trying to build a simple solar panel charging circuit that uses a 5V output solar cell, a 3.7V Li/ion battery and a 3 LED lamp. Simply, the solar panel charges the battery during sunlight, light lights using battery during dark. Anyone have something simple?
Suggest you start with purchasing a small cheap solar powered light like a flower (under $5) that you put in the garden or one that lights up your pathway. Take this apart and analyze the circuit board. It would be a good start.

Jan
 

Thread Starter

jybrooks

Joined Jan 17, 2017
4
I have purchased some TP4056 devices but they only have a set of input and Battery outputs. I have a 4" x 4" solar cell that produces 5V, I have the 3.7V li/ion battery and the 3 LED lamp. How can I use the TP4056 to switch power from the solar cell to the battery and have the light come on when the system switches to the battery?
 

Thread Starter

jybrooks

Joined Jan 17, 2017
4
In response to Jan's post, I purchased a solar powered hanging lamp. That solar array outputs 5V to a board that switches the 3.7V battery voltage to an LED light in the evening, otherwise the solar panel charges the batter and the light is off. My issue is that the charging board only outputs 2-2.5V, so the 3.7V battery never charges fully.
 

mcgyvr

Joined Oct 15, 2009
5,394
In response to Jan's post, I purchased a solar powered hanging lamp. That solar array outputs 5V to a board that switches the 3.7V battery voltage to an LED light in the evening, otherwise the solar panel charges the batter and the light is off. My issue is that the charging board only outputs 2-2.5V, so the 3.7V battery never charges fully.
But was that in 100% direct full noon sun?
Probably not a lithium battery either..
 

Thread Starter

jybrooks

Joined Jan 17, 2017
4
Sorry for the confusion. As in my previous post, The hanging lamp has a 3 LED light that is powered by the battery when there is no sunlight, and the solar cell charges the 3.7V Li/ion 2000mAh battery during the daylight hours. Hopefully, this clarifies things. As I also indicated, the switch/charger board only outputs 2-2.5V, so the 3.7V Li/ion battery never fully charges. Anyone have any feedback to help remedy the issue?
 
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