NOTE: This product is only designed for use with solar panels sold at the Adafruit store. We cannot guarantee this will work with solar panels purchased elsewhere. Please purchase this kit and panels from Adafruit to ensure optimized functionality! A 2.1mm adapter is also required to adapt a solar panel to the DC power jack.

Make your projects to go green this summer with our specialized USB/Solar Lithium Ion Polymer Battery charger! This charger is a very unique design, perfect for outdoor projects, or DIY iPod chargers. We've spent over a year testing and tinkering with this charger to come up with a plug and play solution to charging batteries with the sun and we're really pleased with what we ended up with.

Easy to use! Plug the battery into the BATT port using a 2-pin JST cable and the solar panel into the DC jack using a 2.1mm terminal block adapter. Put the solar panel outside (and keep the battery out of the sun, it needs to be kept cool!) to start charging. You can power another project like a Mintyboost at the same time by connecting to theLOAD output port

Our carefully designed charger is designed specifically for solar charging, and will automatically draw the most current possible from the panel in any light condition!

Even thought it isn't a 'true' MPPT (max power point tracker), it has near-identical performance without the additional cost of a buck-converter. Our detailed tutorial on how to use this charger includes a design document explaining how it all works.

For use with Adafruit Lipoly/LiIon batteries only! Other batteries may have different voltage, chemistry, polarity or pinout.

Comes with an assembled charger board, a 2-pin JST cable that will fit into either the BATT or LOAD ports, and a large stabilization capacitor that must be installed in your finished project. Does not come with a Lipoly battery or solar panel  We have updated the design to be a little more compact, have nicer mounting holes, and a 2.1mm DC jack

• 3.7V/4.2V Lithium Ion or Lithium Polymer battery charger
• Charge with 5-6V DC, USB or 6V solar panel!
• Too dark out? Use a USB mini-B cable or a 5V DC adapter
• Automatic charging current tracking for high efficiency use of any wattage solar panel
• Use any 6V solar panel
• Three color indicator LEDs - Power good, Charging and Done
• Low Battery Indicator (fixed at 3.1V) with LED output
• Set for 500mA max charge rate, can be adjusted from 50mA up to 1A by soldering in a resistor
• Will always draw the most current possible from a solar cell - up to the max charge rate!
• Smart load sharing automatically uses the input power when available, to keep battery from constantly charging/discharging
• Temperature monitoring of battery by soldering in a 10K NTC thermistor (not included) - suggested for outdoor projects where the battery may get hot (50°C) or cold (0°C).

TECHNICAL DETAILS

Board / Layout & Schematic files on Github

• Board Dimensions: 41mm x 33mm x 2mm (1.6" x 1.3" x 0.08")
• Thickness with 2.1mm SMT Barrel Jack: 12.6mm / 0.5"

Downloads:

• MCP73871 datasheet
• Board / Layout & Schematic files on Github
• Schematic image on github

Our detailed tutorial on how to use this charger