How Tall are Solar Convection Currents?

[fenderzilla]

If you look at photos of the sun's surface (or, technically, its photosphere) you will see that it looks very grainy, like a mosaic or cobblestone path. The granules you see there - which are roughly the width of Brazil - are the tops of huge vertical currents in the sun's convective zone; Benard cells. I think this is really cool, but I haven't found a ton of information on them. Does anyone know just how tall the individual convection currents are?