  A model consisting of (d+1)-dimensional gravity coupled to spacetime filling
charged branes is used to study the effects of backreaction. The charged black
holes arising from this simple model reflect the non-linearity of the gauge
field and are thermodynamically stable. By analysing fluctuations of the system
we corroborate that at low values of the temperature (or large chemical
potential) backreaction effects from the branes are dominant. We also provide a
generalisation of the Iqbal and Liu strategy to calculate the DC conductivity,
in which a mass term for the gauge field fluctuation is included. This mass
term gives the value of the residue of the pole at zero frequency in the
imaginary part of the AC conductivity, as well as the running of the DC
conductivity with the bulk radius.
