I suggest not to do it. Converting your bitcoin to ethereum is a bad idea because these two coins are highly stable coin in the market and worth holding. If you have enough money in your pocket why not buying another investment like ethereum? And if you dont have enough money, better to stay in bitcoin because it will give you profit.
What do you mean stable? There is no cryptocurrency which is stable because all of them are very high volatile.
Though bitcoin is the king but as always that its volatile. You can compare the last price of last year in December compare with recent price. Its much lower than. But that is the power of crypto. If its not volatile then it will not so popular like now. Its so profitable because of the volatile.