SolarCharger SZBK07V2

I simulated a simpler MOSFET diode control circuit suitable for this design. The updated design uses two 2N7000 MOSFETs in the control circuit. With these MOSFETs there is no need for additional voltage protection diodes which were needed in the original design, so overall the performance is maintained with a simpler circuit.

16 July 2018:  Solved various calibration problems with the voltage and current measurements.

PWM control of the DC  converter appears to work well.

15 July. Working on software – initial version now complete and started testing / debugging

Set up breadboard with Arduino,  voltage dividers and current shunt amplifier, and connected with the SZBK01. The breadboad modeel uses a schottky diode instead of the MOSFET diode at this stage to reduce build time.

14 July 2018. The hardware schematic is completed, subject to sizing of the voltage dividers and current amplifier components.  The calculations are in the spreadsheet in the project documentation on Github.

Started working on the software.

13 July 2018: I decided to try and submit an entry for the .energy harvesting competition. I have been working on this topic for some time but have not created an end product so far. My concept is to create a modular MPPT charger based on a  SZBK07 DC converter, a MOSFET diode and Op-amp current sensor using the 4 milli Ohm resistor in the SZBK01.

Software will be a library with an MPPT class. It will be configurable for battery set points and temperature input. It will have an interface to get logging data out, so that the system integrator can add a display, local data logging or remote logging by WiFi or other technology.

Working on the hardware schematic diagram.