One of the standard dictionaries for contemporary German has added "E-Voting" - and for those remembering discussions about correct spelling of "E-Voting" in German, it is spelled with capitalized "E" and "V" (similiar to "E-Mail") and with a hyphen "-".

In English - following the Chicago school - "e-voting" is not capitalized, only the "E-" at the beginning of sentences or in titles, so it would the be "E-voting".