Weak localization in graphene is studied as a function of carrier density in the range from 1 x $10^{11}$,cm$^{-2}$ to 1.43 x $10^{13}$,cm$^{-2}$ using devices produced by epitaxial growth onto SiC and CVD growth on thin metal film. The magnetic fiel
d dependent weak localization is found to be well fitted by theory, which is then used to analyse the dependence of the scattering lengths L$_varphi$, L$_i$, and L$_*$ on carrier density. We find no significant carrier dependence for L$_varphi$, a weak decrease for L$_i$ with increasing carrier density just beyond a large standard error, and a n$^{-frac{1}{4}}$ dependence for L$_*$. We demonstrate that currents as low as 0.01,nA are required in smaller devices to avoid hot-electron artefacts in measurements of the quantum corrections to conductivity.
