I have a suggestion/addon for your App you maybe like:
Normally i set the Charge-Current to Minimum (in my case 500mA), because in the most Situations i’m able to leave the Smartphone in the Charger for hours (At Work, Home or on long Car-Drives). So it can charge nearly with no heating up the Battery/Device in a Battery-Unhealthy way.
But then there are sometimes Situations i need the Battery to be fully fast charged in a small time, when planning to spontaneous leaving the House within (1-2 hours) for a Bike trip or visiting Places where no Charger is around (open-air bath).
Maybe you can put two buttons on the App-Cover bottom for limited charge (edited in the App under Maximum Charge Current) and Fast-Charge with full power. A Leaf-Icon for Eco-Charging and a Flash-Icon for Fast-Charging for example.
This is just my Idea, take it or leave it if you like. Maybe this is usefull for other Persons too.