I think this article is written on purpose to make a small improvement on googles approach from 5 years ago look more impressive than it is. Here's an image of

I think this article is written on purpose to make a small improvement on googles approach from 5 years ago look more impressive than it is. Here's an image of a "google server" from 2009: http://www.altenergystocks.com/archives/2009/04/leadacid_batteries_and_how_cheap_beat_cool_at_google.html http://www.altenergystocks.com/archives/2009/04/leadacid_bat... The innovation that google made was to first run the mainboards with +12V only, generating all other rails on the mainboard from this supply (that's why only yellow wires are going from the PSU to the mainboard, as can be seen on the back end). The 12V lead acid battery in the front is connected with the black and red wire to the power-supply (you can see the red and black wire also, on the far end of the picture). So the charger was already integrated into the PSU circuit back then, I'd say. From a topological standpoint, I'd claim that this is pretty much the same thing as the microsoft-datacenter approach -- with the exception of running the powersupply with AC (except DC, as the current article seems to imply). Of course battery technology has improved in the meantime, and using LiIon would be just the smart thing to do now.