Just came across http://www.logview.info/forum/index.php?pages/eng/ perfect tool to collect and display U and I informations from battery chargers.
Could be useful with ESCs having a separate data logger., … Works on RaspBerry PI, available with graphical - and command user interface version.
German tool so Forum mostly in German.
Found it on What is a Hobby Charger a battery and charger analysis site from dk.