Adafruit Universal USB / DC / Solar Lithium Ion/Polymer charger - bq24074
This charger is a breeze to use for solar projects: pick up any of our many 3.7V/4.2V LiIon batteries, and a 6V solar panel. Plug the battery into the BATT port using a 2-pin JST PH cable and the solar panel into the DC jack using a 2.1mm adapter cable 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 at the same time by connecting to the LOAD output port, which will never go above 4.4V.
The bq24074 which powers this design is great 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 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, and bit of header. Does not come with a Lipoly battery or solar panel but we do have tons available in the shop that work quite well.
- 3.7V/4.2V Lithium Ion or Lithium Polymer battery charger
- Charge with 5-10V DC, USB or 6-10V solar panel, can have both USB and DC plugged in at the same time, higher voltage source will be used.
- Automatic charging current tracking for high efficiency use of any wattage solar panel
- Use any 6-10V solar panel
- Two color indicator LEDs - Power good and Charging
- Set for 1000mA max charge rate, can be adjusted to 500mA or 1.5A by soldering closed a jumper
- 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, up to 1.5A draw. Load output is regulated to no-more-than 4.4V
- Optional 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).