Sinclair Research "FM Wristwatch Radio", an LCD wristwatch with a radio attached. However, the watch had several problems and never went into full production. Sinclair had long had an interest in electric vehicles, and during the early 1980s he worked on the design of a single-seater "personal vehicle", eventually starting a company called Sinclair Vehicles Ltd in March 1983. He launched the Sinclair C5 electric vehicle on 10 January 1985, but it was a commercial disaster, selling only 17,000 units and losing Sinclair £7,000,000. Sinclair Vehicles went into liquidation later the same year. The failure of the C5, combined with those of
Sinclair C5 expensively) on the aerodynamics rather than the cycle technology around which the C1 was based. The weight of the vehicle increased to over , far more than Sinclair's desired specification. By March 1983, Sinclair and Wood Rogers had decided to stop the C1 programme. Wood Rogers comments that Ogle were convinced that the C1 would be a flop, telling Sinclair that it would not be fast enough, that its drivers would get wet when it rained and that the battery was not good enough. To meet the steadily escalating development costs of the vehicle, Sinclair decided to raise capital by