Power Supply Unit (PSU) - Geowissenschaften/EXCISS GitHub Wiki
charger BQ25700A
http://www.ti.com/product/BQ25700A
http://www.ti.com/lit/ds/symlink/bq25700a.pdf
gauge BQ40Z50-R2
http://www.ti.com/product/BQ40Z50-R2
http://www.ti.com/lit/ds/symlink/bq40z50-r2.pdf
Technical Reference & SMBus register documentation http://www.ti.com/lit/ug/sluubk0a/sluubk0a.pdf
external resources
https://github.com/ArminJo/Smart-Battery-Module-Info_For_Arduino