Updated schematics

A project log for [WIP] Solar powered supercap balcony lights

Purpose of this project is to create batreryless light for balcony.

andrey.malyshenkoandrey.malyshenko 11/15/2019 at 19:350 Comments

Next i did some calculation and changed my mind regarding schematics. Seems that with this tiny cell that i plan to use, light would be either not very bright or it will work for an hour at best. Therefore i did some research online and prepared schematics with MPPT IC and constant current driver.

(NB: this schematics didn't work quite as expected, pls see updated one later in the project log)

First part is SPV1040T driven MPPT charging driver. Scematics is directly from datasheet.

Second part is MCP1640 boost converter driven by INA199 current shunt monitor. Simple idea here is that INA199 monitors current through shunt resistor and as voltage from cap drops it sends higher feedback voltage to boost converter to boost it up even more. And this goes until cap is almost dried out (MCP1640 will work down to 0.35 volts on its input)

Last part is photoresistor driven enable pin on boost converter. This should start discharge only when it gets dark.

NB: This is not yet tested and few adjustment will be made in the process.