I remember a presentation by Amazon at AnDevCon describing a similar setup they use internally as part of their validation. The built in Android battery profil

I remember a presentation by Amazon at AnDevCon describing a similar setup they use internally as part of their validation. The built in Android battery profile wasn't sufficiently accurate to what was actually causing drain (most OEMs don't modify the default AOP power profile to represent what their system components actually consume in power). They actually went to the point to connecting into the battery electronics on the battery side to monitor drain. Unfortunately I don't see the presentation available online and this was at least 4 years ago.