I am buying this to track my electricity costs specifically for the car. I will use one of the two clip-on induction current transformers with wireless transmitters. Might have to use both as it is a two-phase load which may require clipping them inside the box where each phase wire is separate.
http://www.sears.com/shc/s/p_10153_12605_SPM2820899802P?ci_sku=SPM2820899802&ci_src=14110944&i_cntr=1327549884712&sid=IDx20070921x00003a
http://www.sears.com/shc/s/p_10153_12605_SPM2820899802P?ci_sku=SPM2820899802&ci_src=14110944&i_cntr=1327549884712&sid=IDx20070921x00003a