All sweetness and flavour is extracted through prolonged cooking. The carrots will end up tasteless. But the sweetness will be fermented out if you use only a kilo of sugar. Carrots contain roughly the same amount of sugar as blackberries! At a pinch, you could use washed baby carrots, thus avoiding scrubbing and chopping. A juice extractor requires a fair amount of washing up and even without the raisins, you still need to simmer the juice with the sugar, but don't ask me why. Possibly something to do with driving off the sulphur present in root vegetables. Rather than just citric acid, consider a blend of tartaric, malic and citric acid. If chopping raisins is too much of a chore, you can use Youngs wine enhancer, which is pure grape juice concentrate or a litre of white grape juice. Carrots contain pectin, so add pectolase to the cooled must, to help speed up clearing. Either way, it will take time to mature. Carrot wine used to be called 'whiskey', not because of its alcoholic strength, but due to its somewhat harsh 'kick'!