if you stuck two AA batteries in your brain you might think they'd be enough to power it all day but your brain actually uses the same amount of power as a light bulb at any given moment that means you would need over 160 AA's for just one day of brain power and to run it for a year would take nearly 60,000 batteries enough to fill an entire dumpster and over your lifetime your brain would use over 4 million of them and if you stack them up they'd reach more than halfway to the International Space Station