This project is to power a security camera system on a location without mains power. The system claimed a battery life of one month, but I found it was pretty much flat after a week with normal settings.
So I have a few solar panels ( 170x170 ) left over from another project, and a CN3791 based MPPT single cell charger.
Search AliExpress or ebay for CN3791. They come in different voltages, so make sure you get one that's suited to your solar panel.
In my case I used the 12V version.
To convert the 3.7-4.2V from the lithium cell to 5V I ended up with a DFRobotics board from Core Electronics.
https://core-electronics.com.au/dc-dc-boost-power-supply-module.html they come in a pack of 5 for $8.55 plus shipping, if you buy from Core, then choose the envelope shipping option, as the boards are tiny and fit nicely in a plain envelope.
They are jumper selected for output voltage, and with 5V selected that are good for 1 amp. They have a blue LED, that could probably be removed if you
wanted to minimize quiescent current draw.
The system was packaged up in a plastic box with a magnet glued to the inside of the box, so no mounting holes were needed for installation, if just locks onto the steel rafter with the magnet.
The lithium cell is a 18650, and a voltmeter is connected across the battery with a push button switch, so I can just press the button and get battery voltage.
Everything is mounted with hot melt glue.
I put together another one for more experimentation, this time using a LiPo battery from a failed power bank.
And soldered a USB type A connector to the DFR0952.
The finished solar power bank looks like this...
The solar panel is STAR SOLAR CNC170x170-18 Which I think is 4.5W nominally.
So I have a few solar panels ( 170x170 ) left over from another project, and a CN3791 based MPPT single cell charger.
Search AliExpress or ebay for CN3791. They come in different voltages, so make sure you get one that's suited to your solar panel.
In my case I used the 12V version.
To convert the 3.7-4.2V from the lithium cell to 5V I ended up with a DFRobotics board from Core Electronics.
https://core-electronics.com.au/dc-dc-boost-power-supply-module.html they come in a pack of 5 for $8.55 plus shipping, if you buy from Core, then choose the envelope shipping option, as the boards are tiny and fit nicely in a plain envelope.
They are jumper selected for output voltage, and with 5V selected that are good for 1 amp. They have a blue LED, that could probably be removed if you
wanted to minimize quiescent current draw.
The system was packaged up in a plastic box with a magnet glued to the inside of the box, so no mounting holes were needed for installation, if just locks onto the steel rafter with the magnet.
The lithium cell is a 18650, and a voltmeter is connected across the battery with a push button switch, so I can just press the button and get battery voltage.
Everything is mounted with hot melt glue.
I put together another one for more experimentation, this time using a LiPo battery from a failed power bank.
And soldered a USB type A connector to the DFR0952.
The finished solar power bank looks like this...
The solar panel is STAR SOLAR CNC170x170-18 Which I think is 4.5W nominally.