Charging infrastructure is a significant investment on top of the purchase cost of electric HGVs, therefore decisions to minimise the charging infrastructure requirements, meanwhile future proofing options for maturing technology, need to be informed by computer simulation that will build confidence and facilitate the evaluation of various options. This paper describes the investment challenges and use of a new digital model for computer simulation of fleet depot based electric HGV charging infrastructure. This enables the evaluation of fleet and infrastructure technical options, provides costs for investment decisions, and guides operational planning.