I have always thought that our batteries should be charged at a 3.6 - 3.7 volts setting. This charger on the simple mode, charges at the 4.2v setting. The only thing I have to set is the milli amp charging rate, which I usually use the .5 setting. Is the 4.2v actually ok to use? Do I need to use a different mode so I can choose the 3.7v setting? Thanks.