Jeff Peterman wrote:
First, nearly everything cited is from more than 15 years ago, and there have been big advances in battery design and battery electronics since then. Second, and key, is the statement:
"Charging is controlled via your device's battery charge controller, which is a chip that carefully controls the voltage and current to charge your battery as fast as possible within the safety limits. Apps cannot influence this process."
The statement points out my biggest concern - apps can't really do much. All they can do is monitor and display the battery usage/charging.
The reality is that the battery's electronics may already limit max charge to something less than 100% than the full capacity of the battery, and they may already have smart features that regulate the charging rate to protect the battery while maximizing charging speeds.
As an example, I have a Samsung Active watch that charges really slowly not matter which charger I use because its electronics limit the charging rate - and it will stop charging and report a charging error if I use some chargers that try to bypass the limit.
From what I read on their page, I don't think they disagree with any of your statements. In fact I think they said something very similar.
I think what they've done is create an algorithm for measuring battery health based on data the app collects in each phone during charging. In other words, the app does not control the actual charging process. The phone and charger do. But the app can measure what is happening during charging, and this data is used to plot each battery's projected health.
"We've gathered millions of data points on multiple devices to model the battery wear. As every battery has their own discharge voltage profile, we've verified that we can use the discharge curve to map percentages to an "idealized voltage" which then is used to feed the charging from x to y causes z cycles of battery wear algorithm. The absolute voltages can differ between devices, but the general shape of the discharge voltage curve is bound to how Lithium-ion batteries behave as a class and are comparable between devices."