A DIY Solar Charger for 18650 Lithium Ion cells.

Get off-grid, power your remote project and learn about solar power with this DIY solar charger kit.

This is a relatively simple open-source kit, sold at www.curiouselectric.co.uk and on Tindie: https://www.tindie.com/products/reinnovation/solar-matic/, which includes two 1Wp solar PV panels and all the parts required to recharge standard 18650 lithium ion cells.

The charger IC is the BQ24210 from Texas Instruments. This is an amazing single-cell Lithium Ion battery charge IC with up to 800mA current rating. It is designed to maximise the output from a solar PV cell into the battery. This is a very small surface mount component in a WSON-10 package, so we have soldered this to the PCB for you.

The kit is uses a DC-DC converter which ensures a regulated 5V output, either for a USB connector output or for screw terminals. The DC-DC converter is controlled via a switch on the side of the PCB.

The unit comes with a simple laser-cut enclosure so it can be placed on a window-sill or hung somewhere.

This is a reasonably simple kit which requires some soldering and a few fiddly connections.

Note: Depending upon the capacity of the 18650 cell, in the UK the battery will fully recharge in around 3-5 days during an average summers day. This totally depends upon the solar resource available.

Note: The enclosure is NOT waterproof or for outdoor use.

This repository is for all the design files for this project. This includes:

• PCB design (KiCAD files)
• Enclosure Design (.dxf designs)
• Instructions (open-office and .pdf)