On 23 February 2019, a Raytheon B200 King Air which had recently departed Saanen was passing FL155 for cleared altitude FL240 when a total electrical failure occurred. On subsequently making contact with ATC on a hand-held personal radio, the pilot advised his intention to exit controlled airspace and complete an already commenced visual diversion to Lausanne which was then done. It was found that complete failure to use the prescribed normal checklists had resulted in an undetected electrical system selection error which had led to the successive discharge of both main batteries when corresponding alerts and warnings also went unnoticed.