Hello steemate if you own less than 1 ethereum and you want to convert it to btc. If you notice trading site require you 1 ethereum or more than one.
Then this how to do it. First download coinomi apps, its a mobile apps than support multi alt coin wallet. Then after that installed send your ethereum to coinomi wallet.
Then look for exchange.
You can now exchange to btc or other altcoin less hassle no worries. And by the way exchanger is powered by shapeshift.io happy converting.. hope it HELP..