I am contemplating a change to 12 volts for my C twin,( J.G. regulator). There must be many members who have already done this, but is there a 12volt battery available of sufficient capacity that will fit into a replica battery box to preserve original appearance, or what is the common method of achieving this happy state? I do not want to mount it 'as is', as those I have seen done in this way look out of place, as does a purpose made plain metal box to accomodate the larger battery. All suggestions welcome.