A breakout for the CN3083 lipo charger. I have several of these PCBs if you'd like to try one out.

We have found this particular chip works very well for solar/lipo UKHASnet nodes, and appears to be very efficient at charging the batteries in suboptimal lighting.

Parts list:

• C2 22uF
• C1 4.7uF
• R2 3.6k (for 500mA charge current)
• R1 330
• R3 (not fitted)

R2 (ISET) sets the charge current. The value above is for the maximum current this chip can support (500mA). If you have a smaller lipo (you shouldn't charge at more than 1C), then change the value of this resistor (see datasheet).

The lipo float voltage is set at 4.2V by default. If you'd like to change this, you need to cut jumper SJ1 (which is connected by default) and place resistor R3 to set the float voltage, see the datasheet for calculation of this.