If you have a leisure battery, of say 110 amp. and you wsh to fit another, Why do people state you have to have two new ones? why can you just not join the two together? If you did what is the Dr pepper? (worse that could happen). after all the way i see it is that if one battery is fullly loaded after its charge as is the other, power is drawn from one then the other? or am I wrong? Please enlighten me.